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Determination of antioxidant activity in free and hydrolyzed fractions of millet grains and characterization of their phenolic profiles by HPLC-DAD-ESI-MS
Abstract
Over 50 phenolic compounds belonging to several classes, namely, phenolic acids and their derivatives, dehydrodiferulates and dehydrotriferulates, flavan-3-ol monomers and dimers, flavonols, flavones and flavanonols in four phenolics fractions of several whole millet grains (kodo, finger (Ravi), finger (local), foxtail, proso, little and pearl millets) were positively or tentatively identified using high performance liquid chromatography (HPLC) and HPLC-tandem mass spectrometry (MSn). Total phenolic content (TPC) was determined colourimetrically using Folin–Ciocalteu reagent. Antioxidant and antiradical activities of phenolic fractions were estimated using oxygen radical absorbance capacity (ORAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and singlet oxygen scavenging activity. In addition, antioxidant activities of phenolic fractions were determined in a β-carotene linoleate emulsion system. Insoluble bound fraction of kodo millet showed the highest phenolic content as well as antioxidant activity in the in vitro test systems employed. In general, hydroxycinnamic acids and their derivatives were the main contributors (87–98%) to the TPC of insoluble bound phenolic fraction of millet varieties examined. Flavonoids were predominantly present in the free phenolic fractions of two finger millet varieties and included catechin, epicatechin, gallocatechin, epigallocatechin, and procyanidin dimers B1 and B2 among others. The degree of esterification or etherification of phenolics with sugar residues in the soluble fraction changed with the variety. Thus millet grains may serve as a viable functional food ingredient and a source of natural antioxidants.
... The research has revealed that finger millet contains a diverse range of phenolics, however it's evident that phenolic acids and flavonoids have been effectively extracted and utilized rather than phenolics. Chandrasekara & Shahidi, (2011) reported that the seed coat of finger millet has a higher amount of phenolic compounds at 0.8% as compared to whole flour (6.2%). The polyphenol tannins and phenolics are higher, while flavonoids are smaller amount. ...
... Due to the high percentage of tannins present in finger millets serves as a barrier against the fungal infection and enable the grain to withstand with fungus infestation. The important flavonoids identified in finger millets are condensed tannins, quercetin, gallo-catechin, epigallocatechin, catechin, epicatechin, and proanthocyanidins (Chandrasekara & Shahidi, 2011;Udeh et al., 2017). The study of Xiang et al. (2019) revealed that p-coumaric acid and ferulic acid mostly found in the bound form, whereas epicatechin and catechin dominated in the free fraction. ...
... Additionally, result also revealed that roasting also enhance the starch and nitrogen digestion in laboratory conditions. Heating affects the protein digestibility, making them more prone to hydrolysis (Chandrasekara & Shahidi, 2011) (Table 3.). ...
Millets as an efficient as other cereals grains in addressing nutritional insecurity, malnutrition and the challenges posed by burgeoning global population. Finger millet Eleusine coracana (L.) Gaertn is a significant agricultural crop grown in India thriving under different suboptimal agro-climatic conditions. Finger millet is considered as one of the wonder crop that has immense climatic-resilience properties as well as health benefits which are primary attributed to its for its exceptional nutritional profile. Further the phenolic components present in the seed coat exhibit excellent properties namely anti-oxidant, anti-osteoporosis, anti-diabetic and enzymes inhibitory properties. Additionally, it displays seemingly improved healing properties, which makes this crop an excellent candidate for fulfilling major pharmacological requirements. Moreover, the processing of finger millet is a significant factor for their commercial value in marketing but Government support and consumer awareness are essential for explore the whole potential of finger millet to address global challenges. Additionally, research and development are essential to create value-added food products from finger millet, enhancing its potential as a sustainable and climate-resilience crop.
... However, phenolic acids, which are mostly esterified to polysaccharides and provide cross-linking within cell wall polymers, are among the insoluble phenolic chemicals attached to polymers. Current research has unequivocally shown that the kind of millet affects both the shape and amount of phenolic chemicals (Chandrasekara and Shahidi 2011). ...
... It is believed that dietary flavonoids possess antioxidant properties that are greater in potency than the vitamins C and vitamin E (Sokół-Łętowska, Oszmiański, and Wojdyło 2007). Table 3 represents diverse flavonoids present in different millets (Shahidi and Chandrasekara 2013) such as tricin, lucenin-1, daidzein, sponarin, violanthin, orientin, apigenin, isoorientin, vitexin, myricetin, and isovitexin (Chandrasekara and Shahidi 2011;Pathak et al. 2018;Pradeep and Sreerama 2017). Millets' flavonoids possess several therapeutic attributes, including anti-inflammatory, anti-cancer, diuretic, and analgesic effects (Banerjee 2012;Sarita 2016). ...
... Two flavones with antioxidant properties, luteolin and tricin, were identified by Watanabe (1999) from barnyard millet grains. According to Chandrasekara and Shahidi (2011), the millet phenolic extract mostly occurs in the soluble fraction and contains a variety of flavonoids, including flavan 3-ols (namely monomers and dimmers), flavononol, flavonols, and their glycosides, and flavones. Following finger millet, kodo, and foxtail millets had the greatest total flavonoid concentration (2100 µg/g) of a defatted meal. ...
India is dealing with both nutritional and agricultural issues. The maximum area of agricultural land with irrigation capabilities has been largely utilized, while the amount of dry land is expanding. The influence is distinct on farmer's livelihoods and earnings, which ultimately affects nutritional security. In order to attain nutritional security and the goal of SDG (Sustainable Development Goals), millets are sustainable solutions, with respect to high nutritional content, bioactive and medicinal properties, and climate resilience. The nutrient profile of millet includes 60%-70% carbohydrate content, 3.5%-5.2% fat, and 7.52%-12.1% protein sources. A wide spectrum of amino acids, including cysteine, isoleucine, arginine, leucine, tryptophan, lysine, histidine, methionine, tyrosine, phenylalanine, threonine, and valine are generally present in millets. Mineral content in millets includes calcium, phosphorus, potassium, sodium, and magnesium. Additionally, millets are an excellent source of bioactive molecules such as polyphenol, phenolic acid, flavonoids, active peptides, and soluble fiber, which have a wide range of therapeutic applications, including the prevention of free radical damage, diabetes, anti-microbial, anti-biofilm, and anti-cancer effects. This review will focus on the nutritional profile and health benefits of millet considering the present-day food security problems.
... Disrupts litter nitrogen nutrition, also affects photosynthesis and mitochondrial metabolism. [35,36,37] Soybean (Glycine max (L.) Merr). ...
... Numerous studies have demonstrated that pearl millet (Cenchrus americanus (L.) Morrone) whole grains are rich sources of phenolic compounds [35]. Several studies have demonstrated that the outermost layers of the grains possess a high phenolic content [95,96]. ...
Allelopathy in rainfed crop production systems can be a boon or bane for smallholder farmers depending on their crop choices in intercrops, sequences, and rotations. Crop and weed allelopathy can lead to serious problems like poor germination, low crop stand, and reduced crop growth and productivity. Residual toxicity in soil due to allelopathic monocultures and detrimental impacts on ecosystems, human habitats and health are other problems caused by allelopathy. Allelopathy can be exploited to control weeds, reduce herbicide use, avoid herbicide resistance, stimulate crop growth, and enhance nutrient availability. This review aims to provide practical knowledge that can improve the management of farming systems in the semi-arid tropics of the Indian subcontinent, a region prone to allelopathic effects induced by biotic and abiotic stresses. We focus on synergistic and antagonistic allelopathic effects of major cereals, legumes, oilseeds, commercial crops, and weeds and summarise the current knowledge on the mode of release and properties of alle-lochemicals in crops, residue management and their impacts on crops and weeds. We then list options to effectively suppress weeds, reduce risks of residual toxicity in soil and environmental hazards and outline syn-ergistic crop rotations that reduce disease build up and eradicate parasitic weeds in rainfed production systems of the semi-arid tropics. Finally, we highlight research gaps to further improve and employ knowledge of alle-lopathy of weeds and crops for improved crop production, with reduced synthetic herbicide usage.
... These molecules protect the seed from biological contamination and influence the digestibility of the same cereal (Duodu et al. 2003;HAHN 1986). A study conducted by Subba Rao et al. explains that a variety of millet originating from India was found to be rich in protocatechuic acid (45 mg/100 g of flour), followed by other phenolic compounds with a lower content, such as p-Coumaric, caffeic, gallic, vanillic, and ferulic acids (Subba Rao and Muralikrishna 2002), whereas in another study, other fractions of millet grains were evaluated, in particular kodo, finger (Ravi), finger (local), foxtail, proso, little, and pearl millets, suggesting the presence of phenolic compounds such as hydroxycinnamic acids (e.g., caffeic and p-Coumaric acids), hydroxybenzoic acids (e.g., protocatechuic, vanillic, and syringic acids), and flavonoids (catechin and gallocatechin) (Chandrasekara and Shahidi 2011). Because of the presence of these bioactive compounds, sorghum is able to prevent the development of cancers of the gastrointestinal tract (Collins et al. 2024). ...
... Gallic, vanillic, ferulic, caffeic, and p-Coumaric acids, 3deoxyanthocyanins, and proanthocyanidins B-type (Dykes and Rooney 2006); catechin and gallocatechin (Chandrasekara and Shahidi 2011), as well as starch, unsaturated fatty acids, and proteins. (Stefoska-Needham 2024) (Duodu et al. 2003;HAHN 1986) prevent the development of gastrointestinal tract cancers (Collins et al. 2024) and chronic diseases. ...
The Abruzzo region boasts a wide range of typical food products including cereals, legumes, and vegetables. In this context, they take part in the Mediterranean diet, a dietary model that has been shown to have a fundamental role in the prevention of chronic diseases and benefits for the consumer's health. This review aims to collect, describe, and identify cereals, legumes, and vegetables mostly consumed in the Abruzzo region (Italy) from 2020 till now, pointing attention to their biological effects and nutritional value. In this review, we collected the research works previously reported in literature from 2020 till now using common online research tools such as PubMed and Google Scholar by keywords and most cited papers, providing a general overview of the topic, the clinical trials, and the scientific studies conducted on the described typical food matrices of the Abruzzo region. Some of Abruzzo's nationally recognized traditional products appear on the list of traditional food products (PAT) and are also recognized as Slow Food Presidia. This international association supports producers who preserve gastronomic traditions and safeguard the biodiversity of ecological food production methods. Several studies indicate that the biologically active compounds and phytochemicals found in cereals, legumes, and vegetables commonly consumed in the Abruzzo region offer beneficial effects for the prevention and treatment of metabolic diseases.
... Flavonoid is a vital antioxidant contributing to a low risk of chronic diseases. In terms of flavonoid content, finger millet has a higher range than foxtail and proso millets, with flavanols being the principal subclass [58]. Other phenolic compounds that belong to various flavonoid subclasses include flavones, isoflavonoids, flavonols, and dihydroflavonols, including their glycosides. ...
... Injera Injera is an Ethiopian unleavened fermented flatbread characterised by honeycomb appearance, thin and rollable texture, and sour taste-a result of natural fermentation. In appearance, injera resembles pancake and tortilla [58]. Where pancake is made from wheat flour and tortilla from corn flour, injera is made from teff flour. ...
Millet grains are essential foods for most people living in rural areas with low socioeconomic status, especially in Asia and sub-Saharan Africa (SSA). The most cultivated millets in SSA are pearl millet (Pennisetum glaucum), finger millet (Eleusine coracana), fonio (Digitaria exilis), and teff (Eragrostis tef). Others from around the world are Japanese Barnyard millet (Echinochloa frumantacea); foxtail millet (Setaria italica) and proso millet (Panicum miliaceum), Kodo millet (Paspalum scrobiculatum), and little millet (Panicum sumatrense). The main databases used for this review paper were Web of Science and Scopus. Science Direct and Google Scholar were also used for identifying keywords. The total number of articles used were 110. This review paper explored the origin, physical structure, nutritional composition, and phytochemicals of millet grains. The effect of different processing methods on the nutritional, antinutritional and bioactive compounds of millet products was discussed. Moreover, some traditional products made from these grains were reviewed. The challenges that pertain to the migration from major cereals to millet-based products and future perspectives were given. We advocate the need to create value-added products from these underutilised millets species for commercialisation and food security in line with the second sustainable development goal.
... (Ignacimuthu and Ceasar, 2012;Satish et al., 2016) [4,5] . Additionally, it contains large concentrations of polyphenols (Chandrasekara 2011) [13] and amino acids (Bhatt et al., 2016) [7] such as methionine, lysine, and tryptophan. Antioxidants and vital amino acids abound in grain protein. ...
... (Ignacimuthu and Ceasar, 2012;Satish et al., 2016) [4,5] . Additionally, it contains large concentrations of polyphenols (Chandrasekara 2011) [13] and amino acids (Bhatt et al., 2016) [7] such as methionine, lysine, and tryptophan. Antioxidants and vital amino acids abound in grain protein. ...
Thirty RAPD primers were utilized to identify the genetic variability of nineteen-finger millet genotypes using Random Amplified Polymorphic DNA (RAPD) molecular markers. A set of 15 RAPD markers that were among the primers used demonstrated polymorphism, and banding patterns were rated as 1 (present) or 0 (missing) in the datasheet. This data was then examined using SAHN clustering and Jaccard's similarity coefficient. The degree of polymorphism among the genotypes of finger millet was evaluated using the number of alleles, PIC value, and heterozygosity for each of the 15 RAPD markers. Fifteen polymorphic RAPD markers had 107 polymorphic loci in total. In 15 RAPD, the number of alleles generated per locus varied from 3 (OPD-13) to 13 (OPA-12). The average PIC value, according to RAPD analysis, was 0.33. In the marker analysis, the 19-finger millet genotypes were divided into two major clusters based on the data produced. Ten genotypes were displayed in RAPD cluster I, and nine genotypes in cluster II.
... This fortification increases dietary fiber, improves the glycemic index, and enhances the availability of vital nutrients. Moreover, it aligns with global and national initiatives like the International Year of Millets 2023, which emphasizes the role of millets in ensuring food security and promoting sustainable agricultural practices (Chandrasekara & Shahidi, 2011;Nazni & Bhuvaneswari, 2015). Evaluating the sensory attributes, nutritional composition, and shelf-life stability of fortified chikki is critical to its acceptance and market potential. ...
... 3. Black dates were purchased from local market. 4. Kodo millets was purchased from local market. ...
... These chemicals include potassium, glucosides, folic acid, carotenoids and coumarins, and niacin (Viswanath et al. 2009). These naturally occurring substances are recognized for their ability to function as scavengers of free radicals, regulate enzymatic functions, and offer protection against several ailments, including cardiovascular conditions and some types of cancer (Chandrasekara and Shahidi 2011). Millet grains are potential sources of polyphenols. ...
... Millets contain a significant amount of flavonoids (Sokół-Łętowska et al. 2007). Millets are usually discovered to include flavonoids such as luteolin, quercetin, apigenin, orientin, isoorientin, vitexin, myricetin, sponarin, isovitexin, daidzein, lucenin-1, violanthin, and tricin (Pradeep and Guha 2011;Chandrasekara and Shahidi 2011;Pathak et al. 2018). Flavonoids from millets have demonstrated a broad range of medicinal qualities for use in medicine and clinical settings, including anti-inflammatory, antihypertensive, diuretic, analgesic, anticancer, and hypolipidemic actions (Banerjee 2012;Sarita E.S. 2016). ...
Producing alternative staple foods like millet will be essential to feeding ten billion people by 2050. The increased demand for millet is driving researchers to improve its genetic variation. Millets include protein, dietary fiber, phenolic substances, and flavonoid components. Its climate resilience makes millet an appealing crop for agronomic sustainability. Integrative omics technologies could potentially identify and develop millets with desirable phenotypes that may have high agronomic value. Millets’ salinity and drought tolerance have been enhanced using transcriptomics. In foxtail, finger, and pearl millet, proteomics has discovered salt-tolerant protein, phytohormone-focused protein, and drought tolerance. Metabolomics studies have revealed that certain metabolic pathways including those involving lignin, flavonoids, phenylpropanoid, and lysophospholipids are critical for many processes, including seed germination, photosynthesis, energy metabolism, and the synthesis of bioactive chemicals necessary for drought tolerance. Metabolomics integration with other omics revealed metabolome engineering and trait-specific metabolite creation. Integrated metabolomics and ionomics are still in the development stage, but they could potentially assist in comprehending the pathway of ionomers to control nutrient levels and biofortify millet. Epigenomic analysis has shown alterations in DNA methylation patterns and chromatin structure in foxtail and pearl millets in response to abiotic stress. Whole-genome sequencing utilizing next-generation sequencing is the most proficient method for finding stress-induced phytoconstituent genes. New genome sequencing enables novel biotechnological interventions including genome-wide association, mutation-based research, and other omics approaches. Millets can breed more effectively by employing next-generation sequencing and genotyping by sequencing, which may mitigate climate change. Millet marker-assisted breeding has advanced with high-throughput markers and combined genotyping technologies.
... Millets can thus be helpful in solving problems like lowering atmospheric carbon dioxide and climate uncertainty [3]. Apart from their greater agricultural yield, millets are preferable to staple grains like wheat and rice due to their significant nutritional content, which includes minerals, amino acids, antioxidants, and other health advantages [2,[6][7][8][9]. Research has been done on the nutritional value and biological functions of millet, as well as the processing methods, consumption of different millet-based foods, and health advantages of millet [2,3,[10][11][12][13]. ...
... As a result, it lowers the risk of degenerative illnesses by strengthening the immune system [41]. Antioxidants can be found naturally in millets [2,7]. Furthermore, the ability of millets to scavenge free radicals might not only lower ROS but also offer useful tools for the treatment and prevention of diseases mediated by radicals [11,42]. ...
The global agricultural and nutrition crises are caused by variables
such as fast urbanization, climate change, population growth, water
shortages, and rising dry land. Millets are a popular grain that is
commonly grown in arid and semi-arid parts of the world. Because
of their high vitamin, mineral, phytochemical, and antioxidant
content, millets can serve as a multidimensional answer to the
aforementioned global concerns. A rich source of flavanoids such
as apigenin, catechin, daisein, orientin, isoorientin, lutolin, quercetin,
vitexin, isovitexin, myricetin, sponarin, violanthin, lucenin-1, and
tricin, millets are also high in vitamins. Furthermore, millets'
nutritional potential is enhanced by the inclusion of important amino
acids. Millets' high antioxidant content dramatically lowers the
formation of Reactive Oxygen Species (ROS), which lowers
oxidative stress in human and animal models. Millet has a number
of bioactive components that have been shown to reduce the risk of
cancer, diabetes, heart disease, and aging. However the nutritional and
medicinal potentials of the bioactive chemicals in millets are not
well understood, and there is presently no systematic evaluation of
the literature that includes all the evidence that is now accessible.
... Research has shown that fibre-rich foods improve bowel function (Ambati and Sucharitha, 2019). The millets are rich in antioxidants and fibre content, thus preventing constipation, flatulence, inflammation, and abdominal cramps (Chandrasekara and Shahidi, 2011b). ...
... Additionally, the processing of millets enhances the antioxidant potential (such as peptides) through fermentation and germination (Fernandez et al., 2004). The soluble and insoluble bound phenol extracts of various millets (Kodo, finger, foxtail, proso, pearl, and millet) show antioxidant, chelating, and metal reduction capabilities (Chandrasekara et al., 2011b). The antioxidant activity of roasted millet is higher than that of steamed, probably due to an increase in the extractability of bound phenolics by the thermal breakdown of the cellular components (Pradeep and Sreerama, 2015). ...
... Research has shown that fibre-rich foods improve bowel function (Ambati and Sucharitha, 2019). The millets are rich in antioxidants and fibre content, thus preventing constipation, flatulence, inflammation, and abdominal cramps (Chandrasekara and Shahidi, 2011b). ...
... Additionally, the processing of millets enhances the antioxidant potential (such as peptides) through fermentation and germination (Fernandez et al., 2004). The soluble and insoluble bound phenol extracts of various millets (Kodo, finger, foxtail, proso, pearl, and millet) show antioxidant, chelating, and metal reduction capabilities (Chandrasekara et al., 2011b). The antioxidant activity of roasted millet is higher than that of steamed, probably due to an increase in the extractability of bound phenolics by the thermal breakdown of the cellular components (Pradeep and Sreerama, 2015). ...
... High content of quality protein with balanced amino acid profile; lipid (3%-7%); vitamins; antioxidants; and essential micronutrients, such as Fe, Zn, Mg, and P significantly contribute to its nutritious supremacy [1,3]. PM is the spotlight in combating many diets-related disease such as obesity, diabetes, constipation, and celiac disease due to gluten-free nature [4]. ...
This study investigates the influence of phytic acid on Fe and Zn bioaccessibility and impact of phenolics on free radical scavenging activity in 13 diverse pearl millet (PM) genotypes. Forty‐three phenolic compounds were identified using UPLC‐(ESI)‐QToF‐MS. Free (173.01–217.11 mg GAE/100 g), bound (102.97–142.52 mg GAE/100 g), and total phenolic content (286.04–337.63 mg GAE/100 g) varied significantly among genotypes. Phenolic content positively correlated with radical scavenging activity (36.43%–47.56%, DPPH assay). INFOGEST in vitro digestion showed increasing phenolic bioaccessibility from oral (12.58%–23.55%) to gastric (48.4%–72.25%) to intestinal (67.17%–90.26%) phases. Bioaccessibility of Fe (10.55%–14.46%) and Zn (13.48%–19.79%) was negatively correlated with phytic acid (629.02–797.71 mg/100 g) content. WGI 100, with the lowest phytic acid content, had the highest bioaccessibility, whereas Dedha Bajra, with the highest phytic acid content, had the lowest bioaccessibility of Fe and Zn recorded. PM genotypes are rich in phenolics, having high radical scavenging potential. However, higher phytic acid content reduced Fe and Zn bioaccessibility, reinforcing its antinutritional effect on mineral bioavailability.
... The phytates and polyphenols present in pearl millets assist in controlling aging and metabolic diseases. In addition, the phenolic compounds present mainly in the pearl millets such as p-coumaric and ferulic acids are known to have anti-cancer properties (Chandrasekara and Shahidi, 2011). ...
Millets are increasingly gaining global attention for their immense potential to address major challenges such as hunger and malnutrition, and the climatic risks on agricultural production. With the world’s population steadily increasing, it is essential to find sustainable solutions for regional food and nutrition security, and support the livelihoods of farmers—especially under changing climate. Among various crops, small millets offer a promising yet underutilized option in the pursuit of food and nutritional security. These crops possess superior nutritional profiles compared to traditional staple cereals and demonstrate exceptional resilience to harsh environmental conditions. They can grow with minimal irrigation and thrive on poor-quality soils. This makes millets ideal for sustainable agriculture in challenging environments. This review highlights the current status of small millets, including their nutritional and health benefits, processing techniques, and recent advancements in genomics. It emphasizes the importance of integrating small millets into mainstream agricultural systems and applying omics technologies to fully realize their potential in combating food insecurity under climate stress. Additionally, the review explores modern genomic and genetic engineering approaches that aim to enhance the climate resilience of small millets. By understanding the molecular basis of these traits, researchers can develop improved varieties with greater adaptability and consistent yields under variable environmental conditions. The comprehensive analysis presented in this review serves as a strategic roadmap for leveraging next-generation technologies to improve key traits in small millets. The ultimate goal is to develop superior varieties that can address the complex challenges of agri-food production system under climate uncertainties. Furthermore, the review outlines pathways to increase the commercial appeal and market viability of millets. By focusing on the development and promotion of small millets, the agricultural sector can take significant steps toward achieving food, nutritional, and economic security in the wake of growing global challenges.
... Millet is a staple food in many Asian and African countries and is used to make traditional dishes such as idli, dosa, papad, chakli, porridges, bread, and infant snacks. (Chandrasekara et al., 2011). Consumer awareness of the nutritional, economic, and environmental benefits of consuming millethas increased (Shah et al., 2021). ...
Millets are driven by their health benefits and potential to contribute to food security. Finger millet (Eleusine coracana L), commonly referred to as ragi, provides a rich source of essential nutrients, including calcium, dietary f iber, and various health benefits. Germination is the traditional method used to enhance the high nutritional profile and good functional properties of millet flours while reducing anti-nutritional content. Germination improves the acceptability, digestibility, and bioavailability of nutrients. The purpose of this study was to see the effect of germination on functional properties, flow properties, physico-chemical properties, proximate composition, and pasting properties of finger millet flour. Finger millet seeds were cleaned and soaked for 24 h germinated at room temperature and the sample was collected at 0h, 24h, 48 h and 72 h. Non-germinated and germinated samples were dried and milled into flour. The germination treatment on 48 h finger millet flour was optimized based on functional properties such as bulk density, water absorption capacity, oil absorption capacity, dispersibility, swelling power and solubility. There is no significant differences observed in non-germinated f inger millet flour and optimized germinated flour of flow properties such as carr index, Hausner ratio, and angle of repose. Based on the results, it was concluded that optimized germinated finger millet flour had increased total titratable acidity and good pasting properties compared to non-germinated f inger millet flour. The proximate composition of moisture, protein, fat, ash and fibre content of optimized germinated flour was 9.44%, 8.01%, 2.29%, 2.12% and 4.20% respectively.
... Millets are good for people with celiac disease and are gluten-free. [52,53,54,55] ...
Introduction: Utilising functional foods to avoid diet-related illnesses is becoming more popular in the modern era. For their nutritional and therapeutic benefits, millets are wonderful, nutrient-dense cereals. Millets are possi-ble dietary supplements due to their abundance of all essential elements. Many shreds of evidence show millets have functional and wellbeing‐endorsing effects. Millets in Ayurvedic literature are described as Kudhanya (the inferior of grains), Kshudra Dhanya (little grains), and Trina Dhanya (grains originating from grass). Methodol-ogy: This review encompasses a diverse selection of ancient Ayurvedic texts and modern literature, including textbooks, research articles from databases like PUBMED and MEDLINE, and scientific journals. The focus is on millets and various small grains mentioned in Ayurveda. Result: Analysing ancient sources and several ex-periments reveals that millets have highly nutritious and health‐promoting effects, specifically in diabetes melli-tus, cancer, obesity, cardiovascular disease, etc. Conclusion: The current article suggests that modern living contributes to a rise in non-communicable diseases. Therefore, it is crucial to consume a balanced and nutritious diet consistently. Millets are among the nutrient-dense food crops essential for keeping a healthy diet and ward-ing off numerous illnesses. Once more, raising awareness of millet's nutritional and healing benefits is neces-sary. The scientific community increasingly recognises the significant potential of millets to enhance public nu-trition and combat the worldwide surge in lifestyle-related illnesses.
... In the oral stage, 2.5 g of the sample was homogenized and mixed with 2.5 mL of salivary fluid in a 1:1 ratio and stirred for 5 minutes at a pH of 6.6. The gastric stage involved adding 5 mL of gastric with pepsin, adjusting the pH to 3, and incubating at 37°C for 2 h with pH checks and adjustments every 30 minutes [27]. The intestinal stage commenced by adding 7.5 mL of the simulated intestinal fluid, increasing the pH to 6 -7, and introducing pancreatic fluid. ...
Finger millet (Eleusine coracana) is a nutrient-rich crop widely consumed in developing countries for its potential to combat nutritional deficiencies. However, factors like antinutrients influence nutrient bioaccessibility. This study evaluated the nutritional composition of eighteen varieties (N=18) of finger millet grown at the Kenya Agricultural and Livestock Research Organization (KALRO) in Kisii County, Kenya to identify a variety with the highest levels of Cr3+ and K. The samples were obtained using a randomized complete block design. Mineral content (Cr³⁺, K, Fe, Zn, Mg, Ca, P) was determined via ICP-MS, while antinutrient levels were assessed using Pierce kits and titration methods. Bioaccessibility was measured through in vitro digestion using Caco-2 cells. The IE3779 FM and IE4115 FM varieties contained significantly higher levels (p<0.05) of Cr³⁺ and K respectively hence identified for processing. After processing IE3779 FM variety was identified for bioaccessibility studies due to its higher Cr3+ levels than other varieties. Potassium and chromium are important in T2D diabetic patients if consumed in the recommended amounts. Chromium (iii), Cr3+ and K have been reported to increase insulin sensitivity, lower blood pressure, and boost the immune system. Processing through malting and roasting reduced antinutrients, including tannins, phytates, phenols, and oxalates. Processing decreased tannins, phytates, phenols, and oxalates by 29.11,3.71 %,42.65 %, and 10.71 % on malting and by 24.67 %,8.86 %, 63.29 %, and 7.14 % on roasting IE3779FM variety respectively. Bioaccessibility of Cr3+ and K increased by 2.41 % and 3.5 % on malting, 2.82 % and 31.21 % on roasting. These results underscore the importance of processing to improve nutrient bioaccessibility, making finger millet a valuable food in combating micronutrient deficiencies.
... Various authors have reported on the efects of lactic acid fermentation on millet phenolic content. Some have reported decreases in phenolic content following the fermentation of fnger millet [18][19][20][21]. Tese decreases in phenolic content are, in efect, decreases in the extractability of the phenolics based on the hypothesis that the fermentation process may promote the binding of the phenolic compounds to other molecules such as proteins and carbohydrates, the degradation by microbial enzymes such as polyphenol oxidase, and the hydrolysis of the phenolic compounds [22]. ...
This study evaluated the effects of souring (fermenting using Lactobacillus plantarum and back-slopped inoculum and lactic acid acidification) and cooking of finger millet on phenolic content, radical scavenging properties, and inhibition of oxidative DNA damage in finger millet. Fermentation with Lactobacillus plantarum and back-slopped inoculum, and lactic acid acidification significantly increased the total phenolic content and radical scavenging properties of finger millet extracts, whereas cooking resulted in the reduction of these bioactive properties. Liquid chromatography–mass spectrometry (LC–MS) analysis confirmed the presence of phenolic acids, flavonoids, and proanthocyanidins in finger millet extracts. Both total phenolic acids and total flavonoids were elevated by fermentation (back-slopped inoculum and Lactobacillus plantarum inoculated) and lactic acid acidification but diminished by cooking. Notably, extracts from both unsoured and soured finger millet flour and gruel demonstrated protective properties against DNA damage. These findings suggest that souring enhances the phenolic content and antioxidant properties of finger millet, underscoring the potential of soured finger millet gruels for health promotion.
... 63 The phenolic components, tannins, and phytate found in millet may have the potential to inhibit the initiation and progression of cancer in multiple tissues. 109 Finger millet contains a wide range of these compounds, which may inhibit excessive cellular oxidation and shield against various cancers that are common in the human population. According to research in breast cancer cells, 110 Ferulicacid may function as chemotherapeutic agent against cancer. ...
Millets are important crops in the semiarid tropics of Asia and Africa (especially in India, Mali, Nigeria, and Niger). Finger millet (Eleusinecoracana L.) is stands out as a Nutri-cereal, gluten free making it a versatile and nutritious choice due to good source of carbohydrate (81.5%), protein (9.8%), fat (1.59 g), dietary fiber (11.5 g), phytochemicals, and essential amino acids and its unparalleled richness of calcium (220-450 mg/100 g) and iron (3-20%) compared to other cereals (rice and wheat). Among, the different processing technique, germination is a simple and traditional technique that can also be employed at the household level, which is used to soften the kernel structure, increase the nutritional composition and to enhance nutrient absorption of finger millet grains. The profusion of phytochemicals, a health-promoting reservoir compound in germinated finger millet significantly amplifies its nutraceutical capacity. It possesses notable health-enhancing attributes, including anti-diabetic effects against type 2 diabetes mellitus, anti-diarrheal properties, antiulcer activity, anti-inflammatory characteristics, antitumor effects specifically against K562 chronic myeloid leukemia, anti-atherosclerogenic effect, as well as antimicrobial and antioxidant properties. In terms of functional characteristics, the germination process significantly improves the ability of the millet flour to absorb water and/or oil, its emulsion capacity and stability, but reduced the bulk density and swelling power. This review mainly focuses on the germinated finger millet's nutritional, functional, phytochemical, and therapeutic properties.Household food processing strategy such as germination can be used for improving the nutritional quality to promote finger millet utilization.
... Phenolic chemicals, predominantly located in the bran layers, may be diminished during the milling process when the seed coat detaches [14]. A recent study has definitely shown that the kind of millet significantly influences both the structure and quantity of phenolic chemicals [28]. According to a study, 60% of the phenolic acids found in millet were in a bound form, while the remaining 40% were in the form of free molecules [29]. ...
Millets have garnered growing interest because of their exceptional nutraceutical properties. Due to their abundant supply of vital nutrients and bioactive substances, millets show significant potential in enhancing health and reducing the risk of chronic illnesses. This paper emphasises the significant nutritional content of millets, which are devoid of gluten and abundant in protein, vitamins, and minerals, rendering them a superb dietary choice for those suffering from gluten sensitivity or those in search of functional foods. Furthermore, this paper highlights the main nutraceutical constituents found in millets, such as phenolic compounds, dietary fibre, carotenoids, tocopherols, and phytosterol, and their impact on human health. The exploration of future research pathways is directed towards the optimisation of nutraceuticals derived from millet, the bioavailability of phytochemicals, and the development of novel food processing procedures to augment their health-promoting characteristics. Given the increasing worldwide need for sustainable and nourishing grains, millets are well positioned to have a substantial impact on tackling nutritional and health issues in contemporary diets.
... The broom sorghum grain is rich in starch, protein, fat, trace elements, minerals and polyphenols. It is an excellent food crop [3,4]. With the expansion of its planting area, the yield of straw has also increased. ...
As a large agricultural country, China produces a large number of agricultural and sideline products while harvesting agricultural products every year. Crop straw is one of them. Broom sorghum is a traditional crop in China, which produces a large amount of straw resources every year. These straw resources are placed in the field and cannot be used efficiently. The purpose of this study was to solve the problem of straw utilization of Broom sorghum, one of the main food crops in arid and semi-arid areas of northern China. Broom sorghum is not only a nutritious food crop, its straw is also rich in crude fiber and mineral elements, which has high utilization value. However, due to the high content of lignocellulose in straw, the texture is hard, which limits its digestion and utilization efficiency as feed. In this study, the broom sorghum straw was used as the research object, and the straw raw materials were treated with Lactobacillus plantarum, cellulase and xylanase, respectively. After silage fermentation for 30 d and 60 d, the bags were opened to determine the nutritional quality, fermentation quality, microbial community structure and other indicators. The best fermentation time and additives for broom sorghum straw silage were comprehensively screened to improve the nutritional value of straw and animal production performance. The results showed that the nutritional quality of silage straw increased with the extension of fermentation time. Compared with silage straw after 30 days of fermentation, the nutritional quality and fermentation quality of straw were significantly improved after 60 days of fermentation. Lactobacillus plantarum, cellulase and xylanase could improve the silage performance of broom sorghum straw by improving the microbial community structure in straw, and the effect of cellulase was the best. When cellulase was used in straw at the standard of 20 U/g FM, the content of water-soluble carbohydrates could be significantly increased to 31.35 g/kg FM, and the concentration of lactic acid was also significantly increased to 23.79 g/kg FM. Therefore, in actual production, it is recommended to use cellulase at a dose of 20 U/g FM in broom sorghum silage and open the bag after 60 days of silage fermentation. The results of this study provided a scientific basis for the efficient utilization of broom sorghum straw as feed.
... Mass spectrometry is a widely used as analytical technique for chemical characterization and analysis in different areas, especially food samples (Alves et al. 2010;Chandrasekara, Shahidi, 2011). There are a few reports about the chemical composition of green coffee by Mass Spectrometry (Jaiswal, Kuhnert, 2010;Garrett et al. 2012Garrett et al. , 2014da Rosa et al., 2016). ...
The use of irrigation in coffee aims productivity increase and better quality of the final product. The impacts of irrigation in productivity and quality are impressive. In this study, ten different varieties of Coffea arabica L., were cultivated with irrigation and no irrigation regimes and these samples were analyzed by direct infusion electrospray ionization mass spectrometry (ESI-MS), in positive mode. The constituents identified were choline; trigonelline; sucrose; βN-arachinoyl-5-hidroxytryptamide; βN-behenoyl-5-hidroxytryptamide; palmitoyl-linoleoyl (PL); dilinoleoyl (LL); dipalmitoyl-linoleoyl (PPL); palmitoyl-dilinoleoyl (PLL) and three new compounds reported in coffee – triacylglycerol (TG 54:6), phosphoethanolamine (PE 40:7) and 1-hexadecyl-2-dodecanoyl-glycero-3-phosphate It was possible to efficiently sort the groups of irrigated and non-irrigated using PLS-DA to obtain all the minimum requirements for evaluation of efficiency of the rating model. Sucrose and the ion m/z 431 (not identified) suffered a negative influence of irrigation. The trigonelline, and the ion m/z 723 (not identified) were influenced positively by irrigation. The cup test showed that the coffees cultivated in not-irrigated regime had slightly larger cupping notes that the ones cultivated under irrigation, probably because they presented higher sucrose content.
... Kodo millet is resistant to smut and blast diseases that affect other crops [32]. [33]. ...
... Phenolic acids are further subdivided into hydroxybenzoic acids, hydroxycinnamic acids, hydroxyphenylaceticacids and hydroxyphenylpropanoic acids. Chandrasekara and Shahidi (2011) determined and characterized the free, hydrolyzed (esterified and etherified) and bound phenolic compounds in millet using HPLC-DAD-ESI-MSn. The highest amounts of hydroxybenzoic acid derivatives (62.2 μg/g) and flavonoids (1896 μg/g) were found in the soluble fraction of finger millet. ...
Millet is rich in polyphenols and other biologically active compounds, it is also believed to play a role in lowering the rate of fat absorption and slow release of sugar (low glycemic index), thereby reducing the risk of heart disease, diabetes and hypertension. Due to the increased awareness of millet’s health-promoting profile, there has been an inclination to consume it. This report addresses the agricultural requirements, nutritional information and health benefits offered by these grains. It also examines traditionally produced millet-based products and the latest research conducted around the world. Millet is nutritionally similar or even superior to the major cereals. The additional benefits of millet such as gluten-free protein, high fibre content, low glycemic index and richness in bioactive compounds make it a suitable health food.
... Due to their importance to human health, polyphenol has received a lot of attention (Tsao, 2010). The soluble and insoluble bound phenolic extracts of numerous types of millet, including Kodo, finger, foxtail, proso, pearl, and tiny millets, demonstrate the antioxidant, metal chelating, and reducing properties [11]. Proso millet has 29 mg polyphenolics/100 g and 2.22 mg tocopherol/100 g, compared to foxtail millet's 47 mg polyphenolics/100 g and 3.34 mg tocopherol/100 g (wet basis). ...
There are billions of people who are malnourished and facing food
insecurity worldwide. By 2030, the United Nations has established a
global goal to eradicate hunger, but we are still very far from achieving
it. Food security has been challenged during the past ten years by climate
change, population growth, and economic recession. To attain food and
nutrition security, the food system must be transformed. Today, it is
highly challenging to ensure food security so that the plant can produce
its best products due to environmental stress factors that limit the
production of important cereals. India has food security, but it lags
behind in terms of nutritional security. The world's agriculture has
advanced in many ways, such as biofortification, genetically modified
crops, fortification, etc., but it has neglected the natural gift of nutriacereals,
which are resilient to climate change, highly tolerant of drought
and other extreme weather conditions, rich in high nutrition and dietary
fiber, and serve as good sources of protein, micronutrients, and
phytochemicals. Additionally, it contains phytates, polyphenols, tannins,
anthocyanins, phytosterols, and pinacosanols, all of which are significant
contributors to ageing and metabolic illnesses. Due to their beneficial
nutrient content, which includes carbohydrate, vitamins, proteins, and
minerals, cereals are essential components of a nutritious and healthy
diet. Millets are known as nutri-cereals because of their great nutritional
value and potential to make a significant contribution to food and
nutritional security. Additionally, they show very intriguing nutritional
profiles that include macro and micronutrients as well as bioactive
substances.
... The antioxidant activity Fig. 2. The results disclosed increase in the contour lines of the antioxidant activity activity when approaching towards the kodo millet flour. This is because of the availability of phenolic acids and its derivatives, dehydotriferulates, dehydodiferulates, flavan-3-ol monomers and dimmers, flavones, and flavanols are available in the kodo millet [51]. Regarding prebiotic activity score, it was observed that the coefficient ABC* was maximum, which revealed that prebiotic activity score was predominately affected by the blend of all three millets. ...
Optimization of foxtail, barnyard, and kodo millet, was carried out to formulate millet soup mix by adopting a mixture design. The physico chemical parameters such as pH, Total Soluble Solids (TSS), viscosity, color values (L*, a*, b*), quality characteristics such as soluble, insoluble total fiber, reducing sugar, total phenolic content, and various sensory parameters such as appearance, colour, aroma, taste, and overall acceptability were recorded to assess the effect of selected above three millets on the reconstituted millet soups. Optimization was done and a polynomial model was developed using Response Surface Methodology (RSM) relating to total fiber, antioxidant activity, prebiotic activity score, glycemic index and overall acceptability of the millet soups. Results revealed that there was a significant difference (p < 0.05) observed in the in the pH, TSS, viscosity among ten variations of millet soups. Similar statistical significance (p < 0.05) was noticed in the colour values. Quality characters such as reducing sugar, insoluble, and soluble dietary fiber values were also found to be different between the ten millet soup variations. Highest value of total phenolic content was recorded in MS6 variation with 7.5 gm of barnyard and 7.5 gm kodo millet flour in the millet soup. The overlay plots were used to attain the optimum formulation for the millet soups related to total dietary fiber, antioxidant activity, prebiotic score, glycemic index and overall acceptability which created the yellow region based on the optimized value. The results revealed that the optimum values for the predicted responses were 5.65 g, 24.96%, 0.36, 41.85, 7.65 for the total dietary fiber, antioxidant activity, prebiotic score, glycemic index and overall acceptability, respectively, which was attained from the optimum mixture of 2.14 gm foxtail millet flour, 5.76 gm barnyard millet flour, and 7.11 gm kodo millet flour. From the results the optimized millet soup can be categorized as low glycemic soup (GI < 55) with good prebiotic activity.
... In this study, edible bowl was developed with varying content (30-40%) of little millet, kodo millet, and barnyard millet, along with refined wheat flour and Xanthan gum act as binding agent and food additive respectively served as the base material with jaggery used as a sweetener. Little millet offers anti-cancerous properties and blood sugar regulation [9,10], kodo millet aids in regulating cholesterol, blood sugar for improved cardiovascular health [11], and barnyard millet, with its antioxidants and lower glycemic index, promotes cardiovascular health and is a gluten-free option [12,13] while various phenolic acids found in different millet contribute to human health through their antioxidant properties against oxidative stress-induced complications in chronic diseases [14,15]. It is belief is that these multi-millet edible bowls have the potential to replace plastic bowls, offering opportunities for environmental conservation and eventual sustainable development. ...
Plastic waste presents a significant challenge due to its non-organic nature, leading to a substantial accumulation of plastic waste globally. Plastic bowls, in particular, are widely-used in daily use, making the development of multi-millet edible bowls a viable substitute for traditional plastic options. In this study, we optimized multi-millet edible bowls using major ingredients such as little, kodo, and barnyard millet flours and compared with control edible bowls made from refined flour. The optimised multi-millet edible bowls exhibited significantly lower levels of calories, fat, moisture but higher levels of dietary fibre and protein compared to the control edible bowls. Furthermore, the multi-millet edible bowls exhibited slightly thicker structures, higher hardness but with significantly reduced water absorption properties (~ twofold) and oil absorption properties (~ threefold) in comparison to control. Scanning electron microscopy images of the multi-millet edible bowls revealed the starch granule structure offering valuable insights into their composition. High-resolution mass spectrometry analysis confirmed the presence of 3092 distinct metabolic products, comprising of 24 compounds, including primary and secondary metabolites. Additionally, preliminary soil degradation test indicated that the developed bowls were biodegradable within 42 days. In conclusion, the development of multi-millet edible bowls offers a promising, environmentally conscious alternative to traditional plastic-based bowls and biodegradability.
... The fiber content helps in reducing cholesterol levels, while magnesium helps regulate blood pressure. These factors contribute to a lower risk of cardiovascular diseases (Chandrasekara and Shahidi, 2011). ...
Millet is a staple food crop in many regions of Central and Eastern Africa as well as India. Its rich nutritional content, versatile applications and potential health-promoting qualities position it as a steadfast contender in shaping the future of food and nutrition. Value addition and bio-fortification of nutritional characteristics in millet and their products can make a huge impact to the health of consumers. Popularizing millets and their products can be one promising factor in reaching the goal of achieving zero hunger by the year 2030. This article highlights the importance and health benefits of millets and their value added products which can serve as a benchmark of guidelines for industries, consumers, researchers and nutritionists.
Millet, an ancient whole grain, has a variety of health benefits. Its minerals support bone health. Incorporating millet into a healthy diet can improve overall health and provide a flexible and nutritious grain alternative. Despite its role in providing essential nutrients to the body, millet also has anticancer properties which make it an essential grain for the treatment of different types of cancer. Antioxidants of millets such as flavonoids and phenolic compounds, may help prevent oxidative stress and cellular damage, both of which have been associated with cancer formation. Its high fiber content promotes healthy digestion and intestinal regularity, potentially lowering the risk of colorectal cancer. Certain millet varieties also include lignans, which may alter hormone metabolism, potentially lowering the incidence of hormone-related malignancies such as breast cancer. This chapter will explain the role of different natural compounds and phytochemicals from varieties of millet in the treatment of these two main cancers.
Minor millets are a group of small-grained cereals, extensively cultivated across the arid and semiarid parts of the world. These grains exhibit excellent agronomic traits and are highly nutritious. Minor millet grains are a good source of protein, dietary fibre, as well as micronutrients. These grains also house abundant phytochemicals including phenolic acids and flavonoids and phytosterols. Various processing methods including fermentation, soaking, germination, and malting enhance grain nutrient content and hence influence its bioavailability. Owing to their excellent nutritional and phytochemical composition, minor millets exhibit potential nutraceutical properties. Consumption of minor millet grains can mitigate micronutrient deficiencies and ameliorate diabetes. They also exhibit hypolipidaemic as well as prebiotic potential. Furthermore, minor millets exhibit several health-beneficial effects owing to the bioactivities of phenolic phytochemicals. More research on the health benefits and nutrient bioavailability of minor millets would pave way for optimal utilization of these grains ensuring sustainable nutrition.
Finger millet (Eleusine coracana) is a staple crop in developing countries, offering essential minerals for managing non-communicable diseases, such as chromium (Cr³⁺) and potassium (K), which support insulin sensitivity and lower blood pressure. Despite its nutritional value, finger millet (FM) remains underutilized due to the poor bioaccessibility of its nutrients, influenced by factors such as millet variety, antinutrient content, and processing methods. This study analyzed the levels of selected minerals in 18 finger millet varieties being developed by Kenya Agricultural and Livestock Research Organization (KALRO), Kenya. The superior variety, IE3779FM, in terms of mineral content, was used for further studies on antinutrient and nutrient bioaccessibility. Mineral content (Cr³⁺, K, Fe, Zn, Mg, Ca, P) was determined using ICP-MS, antinutrients (tannins, phytates, phenols, oxalates) were measured by titration and BCA kits, while bioaccessibility was determined using a Caco-2 cell procedure. The different variety of finger millet contain significant mineral levels (0.56–653 mg/100g), exceeding RDA values. Processing of the IE3779FM variety reduced antinutrients by 3.71%–42.65% during malting and 7.14%–63.29% during roasting. Mineral levels were not significantly different between raw and processed forms, attributed to the heat stability of minerals, while proximate composition was minimally altered by processing. Bioaccessibility studies revealed that malting and roasting generally increased mineral bioaccessibility by 0.56%–53.62 % and 0.92-29.39 % respectively. The study concluded that finger millet is rich in essential minerals, and that malting and roasting reduce antinutrients while significantly enhancing mineral bioaccessibility, making it a valuable nutritional source for food formulation for T2D patients.
Millets can be the revolution for developing countries like India. There is a crucial need for millets in the agricultural sector. Other similar cereals present in the market have definitely hindered the use of millets. Millets were the main source of nutrition for the ancient man but with advancing time and introduction to wheat comeback through proper awareness of their nutritional as well as agricultural benefits. Millets have many health benefits. It is has proven to be beneficial in diabetes mellitus due to low glycemic index. For taking in all the benefits which millets can provide one should know their production and processing techniques which are as important as the correct way to consume them. Millets though a very beneficial cereal can be a bit complicated use for the common man because wrong food processing method can truly harm the nutrient content of the millet they are using. Millets do have some anti nutritional factors which can make it a little difficult to digest and can cause an upset stomach for which different processing techniques have been introduced. Each processing technique has different effect on the grains and the factor which influences the technique to be used to process the millet is based on the scale of production and area available. This review basically summaries the various health benefits, nutritional composition along with their processing.
India ranks the second in the population of the elderly aged 60 years and above. India's geriatric population increased from 20 million in 1951 to 100 million (8.3%) in 2014 and is expected to reach 130 million by 2021 as a result of the surge in life expectancy. Due to greater longevity and consequently increase in their population the age-related illnesses of the elderly like hearing loss, cataracts, back and neck pain, osteoarthritis, porous bones, obesity, diabetes, cardiac arrests, depression and dementia etc. have also escalated. Cereals and nutrients packed with vitamins, minerals and fibre may be a good option to prevent or delay the onset of such lifestyle diseases. Millets are also one such affordable cereal options that have nourishing properties and are a splendid source of essential macro and micro nutrients having the potential to cause innumerable health benefits. This chapter describes the health benefits of millets for the elderly enumerating the micro and macro nutrients present in them. It also outlines how millets can aid in preventing many chronic diseases like diabetes, cancer, celiac disease etc. due to being an excellent power house of nutrients.
Keywords: Millets, Old age, Macronutrient, Micronutrient, Super food, Health benefits
Millets have been an integral part of our diet for centuries. Millets aid in the prevention of numerous non- communicable lifestyle diseases such as diabetes, hypertension and cardiovascular diseases and are considered to be potential choice to address the problems of malnutrition and to consequently improve the food and nutritional security of the nation. Recognizing the enormous potential of millets, the Government of India proposed the year 2023 as ‘International Year of Millets (IYM 2023)’ which was accepted by the United Nations General Assembly (UNGA). To support production and consumption of millets, coupled with enhanced consumer awareness of their nutritional and health benefits, a two-day National Conference on ‘Need for Sustainable Development in Food, Agriculture & Allied Sciences’ was organized by Department of Home Science at our campus during December 12-13, 2023. We are delighted to present before the readers a compendium of full length papers, titled ‘Shree Dhanya: Conference Proceedings’.
Hot air puffing system developed is simple, quick and easy to handle. Since the process for hot air puffing of millet grains involved heat treatments, it is necessary to verify the changes occurring during hot air puffing of barnyard millet. Millet is becoming more and more important in a time of rapidly urbanizing populations, shifting lifestyles, convenience, and, most importantly, health consciousness. People are starting to value ready-to-eat (RTE) foods for their convenience. For hot air puffing of barnyard millet, the optimum condition of process variables such as puffing temperature (PT) 310.0 °C, feed rate (FR) 7500.0 g/h, were found and the corresponding optimized quality process parameters were found to be final moisture content (FMC), expansion ratio (ER), puffing percentage (PP), whiteness index (WI), hardness (HD), and crispness (CSP) to be 4.808% db, 2.272, 72.61%, 59.04, 37.66 kg and 75.986 +ve peaks, respectively in the first pass. The unpuffed grains collected together and subjected to second pass of puffing, the unpuffed grains reduced to the tune of 0.81% from 28.39% that was found in first pass. Thus 99.19% of total barnyard millet grains were puffed, giving 72.40% of total sample weight as puffed grain and 26.79% of total sample weight as separate.
In present times millets have been proved to become more significant than staple cereals in terms of productivity and climatic susceptibility. There are many different types of millets being produced in the world today. In this article we have compared various millet varieties available and worked out data about their proteins. Constituent proteins of millets contain leucine, isoleucine, valine, and phenylalanine which are just a few of the crucial amino acids, minerals, vitamins, phyto-chemicals, and anti-oxidant qualities that make these make superior than many cereals. Millets also contains calcium, iron, and zinc. Additionally, millets are useful in treatment of long-term ailments like cancer, CVDs, and diabetes. Millets have also been shown to be effective in reducing bacterial activity, celiac disease, and aging process. In spite of all the health advantages of millet's, anti-nutrients are thought to lower the bioavailability of minerals. Hence, to lower anti-nutrient content and raise mineral bioavailability, a variety of conventional and mechanical processing techniques have been devised, in combination with use of exogenous enzymes. More studies are needed to be carried out to develop novel processing methods, as well as, for analysis of mineral bioavailability of the millet-based foods through in vivo studies, in order to lead a healthy life and maintain a sustainable environment by the humankind. Through the paper we advise to increase millet intake in our daily food.
In present times millets have been proved to become more significant than staple cereals in terms of productivity and climatic susceptibility. There are many different types of millets being produced in the world today. In this article we have compared various millet varieties available and worked out data about their proteins. Constituent proteins of millets contain leucine, isoleucine, valine, and phenylalanine which are just a few of the crucial amino acids, minerals, vitamins, phyto-chemicals, and anti-oxidant qualities that make these make superior than many cereals. Millets also contains calcium, iron, and zinc. Additionally, millets are useful in treatment of long-term ailments like cancer, CVDs, and diabetes. Millets have also been shown to be effective in reducing bacterial activity, celiac disease, and aging process. In spite of all the health advantages of millet's, anti-nutrients are thought to lower the bioavailability of minerals. Hence, to lower anti-nutrient content and raise mineral bioavailability, a variety of conventional and mechanical processing techniques have been devised, in combination with use of exogenous enzymes. More studies are needed to be carried out to develop novel processing methods, as well as, for analysis of mineral bioavailability of the millet-based foods through in vivo studies, in order to lead a healthy life and maintain a sustainable environment by the humankind. Through the paper we advise to increase millet intake in our daily food.
Main conclusion
The review article summarizes the approaches and potential targets to address the challenges of anti-nutrient like phytic acid in millet grains for nutritional improvement.
Abstract
Millets are a diverse group of minor cereal grains that are agriculturally important, nutritionally rich, and the oldest cereals in the human diet. The grains are important for protein, vitamins, macro and micronutrients, fibre, and energy sources. Despite a high amount of nutrients, millet grains also contain anti-nutrients that limit the proper utilization of nutrients and finally affect their dietary quality. Our study aims to outline the genomic information to identify the target areas of research for the exploration of candidate genes for nutritional importance and show the possibilities to address the presence of anti-nutrient (phytic acid) in millets. So, the physicochemical accessibility of micronutrients increases and the agronomic traits can do better. Several strategies have been adopted to minimize the phytic acid, a predominant anti-nutrient in cereal grains. In the present review, we highlight the potential of biotechnological tools and genome editing approaches to address phytic acid in millets. It also highlights the biosynthetic pathway of phytic acid and potential targets for knockout or silencing to achieve low phytic acid content in millets.
Main conclusion
This review discusses the Finger millet's rich nutritional profile, bioactive potential, and industrial applications, combined with its climate resilience, which make it a promising crop for enhancing food security and promoting sustainable agriculture. This review also highlights its significant potential to address malnutrition and mitigate climate change impacts.
Abstract
The emergence of Finger millet from “poor man’s staple food” to “a nutrient rich cereal” has encouraged the need to explore this crop at a wider scale. It is a highly significant crop due to its rich nutritional and bioactive profile, diverse biological activities, and promising industrial applications, along with the high climate resilience. This comprehensive review evaluates its nutritional composition by comparing favorably with other cereals and millets and emphasizing its potential to address malnutrition and enhance food security. Furthermore, it explores the phytochemical/bioactive potential and strategies to enhance their bioavailability followed biological activities of Finger millet by highlighting its various health-promoting properties. The review also discusses industrial potential of finger millet including its role in nutraceutical and functional food production, as well as bioenergy generation. In addition, role of Finger millet as a climate-resilient crop; specifically, the available genetic resources and identification of genes and quantitative trait loci (QTLs) associated with major stress tolerance traits have also been discussed. By providing a comprehensive synthesis of existing knowledge, this study offers valuable insights for researchers, policymakers, and stakeholders engaged in efforts to promote sustainable agriculture, enhance food and nutrition security, and mitigate the impacts of climate change.
The ultrasound-assisted extraction (UAE) of total polyphenols from black bean seed coat (BBSC) was optimized using artificial neural network (ANN) and response surface methodology (RSM). The parameters evaluated included extraction temperature (X1: 30–50 °C), extraction time (X2:20–40 min), and solvent-to-solid ratio (X3: 10–30 mL/g) with ethanol employed as the extraction solvent. The data indicated that polyphenols were efficiently extracted by ultrasonication. According to the predictions of RSM, the predicted UAE conditions for obtaining the maximum yield were 36.07 mg/g total anthocyanin content (TAC), 380.30 mg GAE/g total phenolic content (TPC), 78.15 mg QE/g total flavonoid content (TFC), 85.51% DPPH, and 69.34% ABTS activity. By contrast, the ANN model offered the optimal values of 35.24 mg/g TAC, 338.15 mg GAE/g TPC, 83.63 mg QE/g TFC, 87.59% DPPH, and 75.24% ABTS activity respectively. Results revealed that both ANN-GA and RSM models provided superior predictability and higher accuracy across all response variables. The findings indicated high in vitro digestibility in UAE compared to CSE with reduced time and energy consumption. Further, HPLC profile analysis of in vitro digestion of the extract estimated the highest concentration of tannic acid (110. ± 0.68 µg/g), hesperidin (233.92 ± 0.45 µg/g), and beta-carotene (193.86 ± 0.25 µg/g) and LC-ESI-QTOF-MS identify 38 polyphenol compounds, out of these more than 15 were proposed for the first time in BBSCEx. These findings indicate a highly efficient extraction technique along with an improved statistical methodology.
Graphical abstract
To investigate the antioxidant properties of commercial wild rice, identify and quantify soluble and insoluble phenolic acids in wild rice whole grain, the alkaline hydrolysates from crude methanol extracts (soluble fraction) and residues (insoluble fraction) were separately analysed by high performance liquid chromatography (HPLC) coupled with photodiode array detection (PAD) and quadrupole-time of flight (Q-TOF) mass spectrometry (LC–MS). The antioxidant activity of wild rice methanol extract was found to be up to 10 times greater than that of white rice (control sample) according to their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Ferulic acid was found as the most abundant phenolic acid (up to 355 mg/kg) followed by sinapic acid in wild rice. They both occurred mainly in the insoluble form. Other monomeric phenolic acids present in wild rice consisted of p-coumaric, vanillic, syringic, and p-hydroxybenzoic acids, along with two phenolic acid aldehydes (p-OH-benzaldehyde and vanillin). They were present in both soluble and insoluble forms. Phenolic acid dehydrodimers are cell wall bound and only appeared in the insoluble fractions featured by diferulic acids (DiFA) and disinapic acids (DiSA). The chemical structures of DiFA included 8-8′, 5-5′, 8-O-4′, and 8-5′ (benzofuran form) coupled dimers, with 8-O-4′ as the predominant form (up to 34 mg/kg). DiSA only appeared as 8-8′-coupled products with the linear isomers in the most quantities (up to 19 mg/kg). The DPPH free radical scavenging activities of soluble and insoluble fractions suggest that the antioxidant activity of wild rice is partially attributed to its phenolic acid profile.
Flavonoids normally accumulate in plants as O-glycosylated derivatives, but several species, including major cereal crops, predominantly synthesize flavone-C-glycosides, which are stable to hydrolysis and are biologically active both in planta and as dietary components. An enzyme (OsCGT) catalyzing the UDP-glucose-dependent C-glucosylation of 2-hydroxyflavanone precursors of flavonoids has been identified and cloned from rice (Oryza sativa ssp. indica), with a similar protein characterized in wheat (Triticum aestivum L.). OsCGT is a 49-kDa family 1 glycosyltransferase related to known O-glucosyltransferases. The recombinant enzyme C-glucosylated 2-hydroxyflavanones but had negligible O-glucosyltransferase activity with flavonoid acceptors. Enzyme chemistry studies suggested that OsCGT preferentially C-glucosylated the dibenzoylmethane tautomers formed in equilibrium with 2-hydroxyflavanones. The resulting 2-hydroxyflavanone-C-glucosides were unstable and spontaneously dehydrated in vitro to yield a mixture of 6C- and 8C-glucosyl derivatives of the respective flavones. In contrast, in planta, only the respective 6C-glucosides accumulated. Consistent with this selectivity in glycosylation product, a dehydratase activity that preferentially converted 2-hydroxyflavanone-C-glucosides to the corresponding flavone-6C-glucosides was identified in both rice and wheat. Our results demonstrate that cereal crops synthesize C-glucosylated flavones through the concerted action of a CGT and dehydratase acting on activated 2-hydroxyflavanones, as an alternative means of generating flavonoid metabolites.
Retinopathy is a major cause of blindness in the Western world, while cataract is one of the three major causes of blindness worldwide. Diabetes is one of the major risk factor in retinopathy and cataract. The prevalence of blindness in India is 15 per 1000 while cataract alone accounts for 80% of this blindness. Diabetes induced cataract is characterized by an accumulation of sorbitol which is mediated by the action of a key enzyme aldose reductase (AR). Non-enzymatic glycation (binding of glucose to protein molecule) induced during diabetes appear to be the key factor for AR mediated sugar-induced cataract. Finger millet polyphenols (FMP) being a major anti-diabetic and antioxidant component, we have evaluated them for AR inhibiting activity. Phenolic constituents in FMP such as gallic, protocatechuic, p-hydroxy benzoic, p-coumaric, vanillic, syringic, ferulic, trans-cinnamic acids and the quercetin inhibited cataract eye lens effectively, the latter was more potent with an IC(50) of 14.8nM. Structure function analysis revealed that phenolics with OH group at 4th position was important for aldose reductase inhibitory property. Also the presence of neighboring O-methyl group in phenolics denatured the AR activity. Finger millet seed coat polyphenols (SCP) has been found to inhibit AR reversibly by non-competitive inhibition. Results thus, provide a stronger evidence for the potentials of FMP in inhibiting cataractogenesis in humans.
Digitaria exilis (fonio) is a tiny variety of millet commonly eaten by inhabitants of semiarid regions. A sample of fonio collected right in the middle of a severely iodine-depleted goitrous endemic was submitted to phytochemical investigations in order to assess the potential contributory roles played by vegetable molecules to the goitrogenic processes. The total content of flavonoids amounts to 500 mg/kg of the edible whole cereal grains. Their extraction and identification fail to detect the C-glycosylflavones described in other millet varieties but point out the presence of apigenin (A = 150 mg/kg) and of luteolin (L1 = 350 mg/kg). Ten percent of A and 80% of L1 are present in free form, whereas the remaining 90% of A and 20% of L1 are bound as O-glycosylflavones. Both A and L1 aglycones manifest strong anti-thyroid peroxidase (TPO) activities, resulting in a significant reduction of the hormonogenic capacity of this enzyme. In addition, L1 significantly depresses the cyclic AMP phosphodiesterase, implying a concomitant overproduction of the thyrotropin-dependent nucleotide. These last unreported data are regarded as counteracting to some extent the TPO-mediated goitrogenic properties of L1. Since fonio is devoid of other molecules likely to interfere with the thyroid function, our results are directly and casually attributed to A and L1 found in the customary diet.
Aqueous methanolic extracts of whole kernels from six different barley cultivars, namely, Falcon, AC Metcalfe, Tyto, Tercel, Phoenix, and Peregrine, were examined for their total phenolic content (TPC), oxygen radical scavenging capacity (ORACFL), hydroxyl radical scavenging capacity (HORACFL), potency in prevention of lipid oxidation using the Rancimat method, efficacy in inhibition of Cu(II)induced human LDL cholesterol oxidation, and antiproliferative activities using Caco-2 colorectal adenocarcinoma cell line. Total phenolic content as measured by Folin-Ciocalteu’s method ranged from 0.68 to 1.19 mg of ferulic acid equiv/g of defatted material, whereas ORACFL and HORACFL values were 11.28-19.10 and 9.06-12.99 µmol of Trolox equiv/g of defatted material, respectively. Protection factor (PF), a measure of the effect of extracts on the prevention of oxidation of stripped corn oil as measured by Rancimat, ranged from 0.97 to 1.59. Furthermore, barley extracts showed 19.64-33.93% inhibition against Cu(II)-induced human LDL cholesterol oxidation at a final concentration of 0.02 mg/mL. The proliferation of Caco-2 colon cancer cells was significantly ( p < 0.05) inhibited in a dose-dependent fashion in the presence of all barley extracts tested at the end of the day 4 of incubation. At the end of day 4, barley extracts rendered 29.3-51.2 and 9.3-15.9% inhibition of cell proliferation at 0.5 and 0.05 mg/mL, respectively. Phenolic extracts from whole barley kernel tested possessed high antioxidant, antiradical, and antiproliferative potentials. Therefore, inclusion of whole barley into the daily diet may render beneficial health benefits
Seven isomeric dehydrodimers of ferulic acid (4-hydroxy-3-methoxycinnamic acid) have been synthesized and identified in extracts of saponified cell walls of cocksfoot, switchgrass, and suspension-cultured corn. Dehydrodimers (E,E)-4,4′-dihydroxy-5,5′-dimethoxy-3,3′-bicinnamic acid, trans-5-[(E)-2-carboxyvinyl]-2-(4-hydroxy-3-methoxyphenyl)-7-methoxy-2, 3-dihydrobenzofuran-3-carboxylic acid, (Z)-β-{4-[(E)-2-carboxyvinyl]-2- methoxyphenoxy}-4-hydroxy-3-methoxycinnamic acid, (E)-3-{4-[(E)-2-carboxyvinyl]- 2-methoxyphenoxy}-4-hydroxy-5-methoxycinnamic acid, (E,E)-4,4′-dihydroxy- 3,5′-dimethoxy-β,3′-bicinnamic acid, 4,4′-dihydroxy-3, 3′-dimethoxy-β,β′-bicinnamic acid, and trans-7-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-6-methoxy-1,2-dihydronaphthalene- 2,3-dicarboxylic acid, all arise from oxidative coupling of ferulate esters in cell walls and represent products of 8-5, 8-8, 8-O-4, 4-O-5, and 5-5 radical coupling. Prior literature has acknowledged only the presence of the 5-5-coupled dehydrodimer (E,E)-4,4′-dihydroxy-5,5′-dimethoxy-3,3′- bicinnamic acid. Consequently, by measuring only a single dehydrodimer and assuming inappropriate response factors, ferulate dehydrodimers have been underestimated by factors of up to 20. Synthetic routes to all seven isomers have been developed to provide structural authentication and determination of GC response factors.
Dimers of ferulic acid were chemically synthesized and the antioxidant properties assessed using (a) inhibition of ascorbate/iron-induced peroxidation of phosphatidylcholine liposomes and (b) scavenging of the radical cation of 2,2'-azinobis(3-ethyl-benzothiazoline-6-sulphonate (ABTS) relative to the water-soluble vitamin E analogue, Trolox C (expressed as Trolox C equivalent antioxidant capacity, TEAC). The dimers examined were (E,E)-4,4'-dihydroxy-5,5'-dimethoxy-3,3'-bicinnamic acid (5-5' diFA), trans-5-[(E)-2-carboxyvinyl]-2-(4-hydroxy-3-methoxy-phenyl)-7-methoxy-2,3 -dihydrobenzofuran-3-carboxylic acid (5,8'-BenDiFA) and the methyl ester of 5,8'-BenDiFA, dimethyl-5,8'-BenDiFA. In both assays, the order of antioxidant efficacy was: 5,5'-diFA > 5,8'-BenDiFA > dimethyl-5,8'-BenDiFA. From these results, methyl esterification decreases the antioxidant action. Comparison of the TEAC values shows that 1 mol of each of the ferulic acid dimers tested is less effective than 2 mol of free ferulic acid, and so dimerization decreases antioxidant action of these hydroxycinnamates.
Seven isomeric dehydrodimers of ferulic acid (4-hydroxy-3-methoxycinnamic acid) have been synthesized and identified in extracts of saponified cell walls of cocksfoot, switchgrass, and suspension-cultured corn. Dehydrodimers (E,E)-4,4'-dihydroxy-5,5'-dimethoxy-3,3'-bicinnamic acid, trans-5-[(E)-2-carboxyvinyl]-2-(4-hydroxy-3-methoxyphenyl)-7-methoxy-2,3-dihydrobenzofuran-3-carboxylic acid, (Z)-beta-{4-[(E)-2-carboxyvinyl]-2-methoxyphenoxy}-4-hydroxy-3-methoxy-cinnamic acid, (E)-3-{4-[(E)-2-carboxyvinyl]-2-methoxyphenoxy}-4-hydroxy-5-methoxycinnamic acid. (E,E)-4,4'-dihydroxy-3,5'-dimethoxy-beta,3'-bicinnamic acid, 4,4'-dihydroxy-3,3'-dimethoxy-beta,beta'-bicinnamic acid, and trans-7-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-6-methoxy-1,2-dihydro-naphthalene-2,3-dicarboxylic acid, all arise from oxidative coupling of ferulate esters in cell walls and represent products of 8-5, 8-8, 8-O-4, 4-O-5, and 5-5 radical coupling. Prior literature has acknowledged only the presence of the 5-5-coupled dehydrodimer (E,E)-4,4'-dihydroxy-5,5'-dimethoxy-3,3'-bicinnamic acid. Consequently, by measuring only a single dehydrodimer and assuming inappropriate response factors, ferulate dehydrodimers have been underestimated by factors of up to 20. Synthetic routes to all seven isomers have been developed to provide structural authentication and determination of GC response factors.
Nature of non-starch polysaccharides (NSP) and bound phenolic acids from native and malted ragi were studied using a recently-released hybrid variety of ragi, (Indaf-15). Yields of water-soluble NSP, hemicellulose-B and cellulose polysaccharides increased upon malting whereas a substantial decrease in the yield of hemicellulose-A was observed. Hemicellulose-B is the most viscogenic and its relative viscosity decreased from 3.04 to 1.98 upon 96 h of malting, whereas the solubility and viscosities of the rest of the NSP increased upon malting. The major sugars identified in all the NSP fractions were arabinose, xylose, galactose and glucose. A one- to two-fold decrease in arabinose was observed in all the NSP upon malting except for the alkali-insoluble residue wherein a decrease of glucose was observed. A progressive decrease in the pentose to hexose ratio was observed, indicating mainly pentosan degradation during malting, whereas an increase in the pentose to hexose ratio was observed in the alkaline-insoluble residue (AIR). Ferulic, caffeic and coumaric acids were identified as the major bound phenolic acids in native ragi and one- to two-fold decrease was observed in their contents after 4 days of malting.
The total phenolic acid content of wheat, rice, and oat flours ranged from 71 to 87 ppm while corn flour contained 309 ppm and potato flour 410 ppm. Cis- and trans-ferulic and -p-coumaric acids and syringic acid were the principal phenolic compounds in the free acid or soluble ester fractions of the cereal flours. Alkaline hydrolysis of the insoluble residue of the cereals released the major proportion of phenolic acids, principally trans-ferulic acid. Free chlorogenic acid was the principal phenolic acid in potato flour, and a significant proportion of caffeic acid was released on hydrolysis of soluble esters. Wheat flour which had been stored for 6 months contained only 26 ppm of total phenolic acids, primarily in the bound form.
The cyclodimerisation of trans-p-coumaric (tCA; (E)-3-(4-hydroxyphenyl) propenoic acid) and trans-ferulic (tFA; (E)-3-(4-hydroxy-3-methoxyphenyl) propenoic acid) acids to form substituted truxillic and truxinic acids has been investigated since dimers of this type are present in graminaceous cell waits and are likely to be of importance in limiting wall biodegradability. Irradiation of a thin film of a mixture of tCA and tF A, under ‘daylight’ fluorescent tubes and incandescent lamps in a growth cabinet, produced three cyclodimers corresponding to 16 % conversion of monomers. Under the same conditions of irradiation, a thin film of FA alone yielded only 2% of F A-F A. When tF A crystals were irradiated, no dimerisation occurred, whereas tCA crystals were totally dimerised to CA-CA. Lower yields of dimers were obtained using UV irradiation. The dimers were shown, by capillary gas-liquid chromatography and mass spectrometry, to be derivatives of truxillic acid (t-2, c-4-diphenyl-r-1, t-3-cyclobutanedicarboxylic acid) composed of CA-CA, CA-FA and FA-FA, and to have gas chromatographic retention times identical to those of dimeric compounds found in grass cell walls. The results are considered in relation to dimerisation of phenolic acids in plant cell walls under the influence of sunlight.
BACKGROUND: Kucha (Camellia assamica var. kucha) is a novel wild tea resource grown in China and a tea plant containing a sizable amount of theacrine (1,3,7,9-tetramethyluric acid). High-performance liquid chromatography (HPLC) analysis of purine alkaloids and catechins in young leaves of Kucha has been reported previously. However, the compositions of purine alkaloids and catechins in other parts of the plant remain unknown, and more information about the chemical constituents of Kucha is also necessary for further research and development of this new tea resource.
RESULTS: Using HPLC with diode array detection coupled with electrospray ionisation tandem mass spectrometry (HPLC-DAD/ESI-MS/MS), three purine alkaloids, seven catechins and four non-catechin phenolic compounds were identified or tentatively identified in Kucha. Purine alkaloids and catechins in leaves at different developmental stages, flowers, stems, pericarps and seeds of the plant were also quantified for the first time by the HPLC method, which was fully validated. Recoveries of the quantified compounds ranged from 96.67 to 104.33%.
CONCLUSION: The results showed that the total contents of purine alkaloids and catechins were highest in young leaves of Kucha. Theacrine was detected in all parts of the plant and found to be most abundant in pericarps. Copyright
An optimized high performance liquid chromatography (HPLC) procedure has been developed for the analysis and quantification of all of the known ferulic acid dehydrodimers, and the principle phenolic aldehydes and acids, found in the cell walls of higher plants. The HPLC system uses an ODS2 reverse phase column (5 μm particle size) eluted with a methanol, acetonitrile and water gradient with detection at 280 nm. In addition to providing baseline resolution of most components, the method employs a spectrometric detector which enables the precise identification of eluted components through the analysis of their spectral properties. Analysis of the cell wall phenolics of wheat straw stem (Triticum vulgare) was carried out using this method which is highly versatile and, for certain components, more sensitive than the current gas chromatography–mass spectrometry methodology.
J. Inst. Brew. 114(1), 27–33, 2008 Ten different barley cultivars and their corresponding malts were used to obtain different fractions. Phenolics extracted belonged to free, soluble esters and insoluble-bound fractions. Total phe-nolic content (TPC) of the free fraction, as measured according to the Folin-Ciocalteu method, ranged from 37.7 to 167.2 mg gallic acid equiv/kg of dried material (GAE/kg dw) for barley and between 34.1 and 72.3 mg GAE/kg dw for malt. The bound phenolic content ranged from 210.3 to 320.5 and between 81.1 and 234.9 mg GAE/kg dw for barley and malt, respectively. The contribution of bound phenolics to the TPC was significantly higher than that of free and esterified fractions. Catechin and ferulic acid, quantified by high performance liquid chromatog-raphy with diode array detector (HPLC-DAD), were the most abundant phenolics in the free and bound fractions, respectively. The p-coumaric acid content was lower in hulless genotypes, as compared to hulled genotypes, showing that it is mainly con-centrated in the hull. The antioxidant activities of the phenolic fractions were investigated using the radical scavenging assay (DPPH) and ferricyanide reducing power. The bound phenolics demonstrated a significantly higher antioxidant capacity com-pared to the free and esterified phenolics. During the malting process, a significant decrease of the bound phenolics was ob-served with a corresponding increase of the esterified fraction.
Hydroxycinnamates are among the most widely distributed plant phenylpropanoids present in the free, conjugated-soluble and
insoluble-bound forms. This review will focus on the occurrence, in vitro and in vivo antioxidant activities of ferulic, coumaric,
caffeic and sinapic acids and their derivatives. Hydroxycinnamates are found in almost all food groups though they are abundant
in cereals, legumes, oilseeds, fruits, vegetables and beverages and render antioxidant activity by scavenging hydroxyl radical,
superoxide radical anion, several organic radicals, peroxyl radical, peroxinitrite and singlet oxygen, among others. Further,
their antioxidant activity as chain breaking antioxidants and reducing agents is also notable. Ferulic acid and its derivatives
such as ferulic acid ethyl ester, ferulic acid dehydrodimers, feruloyl glycosides and curcumin have demonstrated potent antioxidant
activity in both in vitro and in vivo systems. Similarly, caffeic acid and some of its derivatives such as caffeic acid phenethyl
ester, rosmarinic acid, and chlorogenic acid exhibit antioxidant activity. The highest antioxidant activity was observed for
caffeic acid whereas p-coumaric acid had the least effect among major hydroxycinnamic acids. The importance of structural effects on the potency
of antioxidant activity of hydroxycinnamates is discussed. While this review also shows the existence of substantial body
of evidences for in vitro antioxidant activity of hydroxycinnamates, there is a clear gap for in vivo information, particularly
for sinapic and p-coumaric acids and their derivatives. The role of grains, fruits, vegetables and red wine in disease risk reduction and health
promotion could partly be attributed to their constituent hydroxycinnamates.
KeywordsCaffeic-Ferulic-In vitro antioxidant activity-In vivo studies-Sinapic
Investigations on insoluble dietary fibre (IDF) of wheat, rye, barley, oat, maize, rice and millet led to the identification
of several new dehydrodimers of ferulic acid (DFA). These compounds arise from 8–8′, 8–5′, 8–O–4′ and 5–5′ coupling. Esterified
phenolics were set free by mild alkali hydrolysis, total amounts of phenolics (ester- plus etherified) were determined by
alkali hydrolysis under pressure. Phenolic acids were analysed by gas chromatography – mass spectrometry (GC-MS) as their
trimethylsilyl (TMS) derivatives and by high performance liquid chromatography – diode array detection (HPLC-DAD). In esterified
form 8–8′aryl DFA and 5–5′ DFA dominate in most cereal IDF with, together, 45–60% of the DFA sum. More than 60% of total bound
DFA are involved in ether linkages. Highest amounts of esterified as well as etherified DFA are estimated in millet, followed
by maize. DFA contents of wheat, rye and barley are about two- to threefold lower than in millet but about twofold higher
than in oat or rice.
HPLC in combination with electrospray ionization mass spectrometric detection in the negative ion mode has been used successfully to investigate proanthocyanidins extracted from malt. Electrospray is a soft ionization technique which offers the possibility of generating only pseudomolecular ions without any fragmentation. The fragmentation pathways of dimeric and trimeric flavan-3-ols were elucidated by multiple stage experiments in an ion trap. It is possible to determine both the molecular weight and the sequence of the monomeric units without preparative isolation of the compounds. As with other mass spectrometric techniques no differentiation between stereoisomers is possible and no information about the position and stereochemistry of the interflavanoid linkage (4→6 or 4→8) is available. It seems to be possible to apply the knowledge of the fragmentation of the analyzed compounds to higher oligomeric or polymeric flavanols.
Phenolic acids from finger millet (Eleusine coracana) milled fractions (whole flour, seed coat, 3%, 5% and 7%) were isolated and their antioxidant and antimicrobial properties were evaluated. Acidic methanol extracts from seed coat to whole flour were rich in polyphenol content and were found to be stable up to 48 h at pH 4, 7, and 9 as studied by ultraviolet spectroscopy. Diadzene, gallic, coumaric, syringic and vanillic acids were identified as major phenolic acids from the extracted phenolics. Diadzene content was highest in concentration in the 5% flour. The reducing power of seed coat extract was significantly (p < 0.05) higher than that of whole flour extract. Antioxidant activity (AA) as determined by the β-carotene–linoleic acid assay indicated that the AA was highest in seed coat extract (86%), whilst at the same concentration it was only 27% in the whole flour extract. The seed coat extract showed higher antimicrobial activity against Bacillus cereus and Aspergillus flavus compared to whole flour extract. From these observations, it can be inferred that the polyphenols are responsible for the microbial activity of the millet and the results indicate that potential exists to utilise finger millet seed coat as an alternative natural antioxidant and food preservative.
Phenolic constituents of six barley varieties, namely Falcon, AC Metcalfe, Tyto, Tercel, Phoenix and Peregrine were separated into free, soluble conjugate and insoluble-bound fractions. Soluble conjugates and insoluble-bound phenolics were extracted into diethyl ether after consecutive alkaline hydrolysis for 4 h. Total phenolic content of each of the three fractions was determined by using Folin–Ciocalteau method. Total antioxidant capacity of the phenolic fractions was determined by trolox equivalent antioxidant capacity (TEAC) assay. The extracts were evaluated for their efficacy in scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Oxygen radical scavenging capacity (ORACFL) of the extracts was determined using a fluorometric assay. Effectiveness of phenolic extracts in inhibiting oxidation of human LDL cholesterol and radical-induced supercoiled DNA breakage was also evaluated. The contribution of insoluble-bound phenolics toward total phenolic content was significantly (p < 0.05) higher than the soluble phenolics for all barley extracts tested. The ratio of soluble to insoluble phenolics ranged from 1:27 to 1:35. TEAC and ORAC values and DPPH radical scavenging capacity of the insoluble phenolic fraction were significantly (p < 0.05) higher than those of their insoluble counterparts. A similar trend was observed against inhibition of LDL cholesterol oxidation and radical-induced DNA breakage.
Oxidative stress, caused by reactive oxygen species (ROS), is responsible for modulating several pathological conditions and aging. Soluble and bound phenolic extracts of commonly consumed millets, namely, kodo, finger (Ravi), finger (local), foxtail, proso, little, and pearl, were investigated for their phenolic content and inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ROS, namely, hydroxyl radical, peroxyl radical, hydrogen peroxide (H(2)O(2)), hypochlorous acid (HOCl), and singlet oxygen ((1)O(2)). Inhibition of DPPH and hydroxyl radicals was detrmined using electron paramagnetic resonance (EPR) spectroscopy. The peroxyl radical inhibitory activity was measured using the oxygen radical absorbance capacity (ORAC) assay. The scavenging of H(2)O(2), HOCl, and (1)O(2) was evaluated using colorimetric methods. The results were expressed as micromoles of ferulic acid equivalents (FAE) per gram of grain on a dry weight basis. In addition, major hydroxycinnamic acids were identified and quantified using high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry (MS). All millet varieties displayed effective radical and ROS inhibition activities, which generally positively correlated with phenolic contents, except for hydroxyl radical. HPLC analysis revealed the presence of ferulic and p-coumaric acids as major hydroxycinnamic acids in phenolic extract and responsible for the observed effects. Bound extracts of millet contributed 38-99% to ROS scavenging, depending on the variety and the test system employed. Hence, bound phenolics must be included in the evaluation of the antioxidant activity of millets and other cereals.
Soluble and insoluble-bound phenolic extracts of several varieties of millet (kodo, finger, foxtail, proso, pearl, and little millets) whole grains were evaluated for their phenolic contents and antioxidative efficacy using trolox equivalent antioxidant capacity (TEAC), reducing power (RP), and beta-carotene-linoleate model system as well as ferrous chelating activity. In addition, ferulic and p-coumaric acids were present in soluble and bound phenolic fractions of millets, and their contents were determined using high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry (MS). Kodo millet had the highest total phenolic content, whereas proso millet possessed the least. All millet varieties showed high antioxidant activities, although the order of their efficacy was assay dependent. HPLC analysis of millet phenolic extracts demonstrated that the bound fractions contained more ferulic and p-coumaric acids compared to their soluble counterparts. The results of this study showed that soluble as well as bound fractions of millet grains are rich sources of phenolic compounds with antioxidant, metal chelating, and reducing power. The potential of whole millets as natural sources of antioxidants depends on the variety used. The importance of the insoluble bound fraction of millet as a source of ferulic acid and p-coumaric acid was established, and their contribution to the total phenolic content must be taken into account in the assessment of the antioxidant activity of millets.
Liquid chromatography, with diode array detection and electrospray ionization mass spectrometry (LC-DAD-ESI/MS), was used to identify and quantify flavonoids in cashew apple. One anthocyanin and thirteen glycosylated flavonols were detected in a methanol-water extract. Among them, the 3-O-galactoside, 3-O-glucoside, 3-O-rhamnoside, 3-O-xylopyranoside, 3-O-arabinopyranoside and 3-O-arabinofuranoside of quercetin and myricetin, as well as kaempferol 3-O-glucoside were identified by direct comparison with standards or positively identified flavonoids in cranberry. The anthocyanin was the 3-O-hexoside of methyl-cyanidin. Trace amounts of delphinidin and rhamnetin were detected in the hydrolyzed extract, suggesting their glycosides were present, but undetectable, in the original extract. The concentrations of the 14 flavonoids in the tested sample were determined. This is the first report of these flavonoids in cashew apple.
The objective of this study was to determine and compare the total phenolic content and antioxidant capacity in the seeds, skin, and pulp of eight cultivars of Florida-grown muscadine grapes and to identify the phenolic compounds in these respective portions. Total phenolic contents were determined colorimetrically using Folin-Ciocalteu reagent, and antioxidant capacity was determined by oxygen radical absorbance capacity (ORAC). High-performance liquid chromatography equipped with diode array (HPLC-DAD) and electrospray ionization mass spectrometric detection (ESI-MS(n)) was used to identify the phenolic compounds in the seeds, skin, and pulp of muscadine grapes. The total phenolic content and antioxidant capacity, based on fresh weight, were highest in seeds followed by skin and pulp. On average, 87.1, 11.3, and 1.6% of phenolic compounds were present in seeds, skin, and pulp, respectively. A total of 88 phenolic compounds of diverse structures were tentatively identified in muscadines, which included 17 in the pulp, 28 in the skin, and 43 in the seeds. Seventeen compounds were identified for the first time in muscadine grapes. The compounds identified in seeds included hydrolyzable tannins, flavan-3-ols and condensed tannins, ellagic acid derivatives, and quercetin rhamnoside. The skin contained hydrolyzable tannins, flavonoids, including anthocyanin 3,5-diglucosides, quercetin, myricetin, and kaempferol glycosides.
The phenolic and tannic composition of heartwood extracts from Prunus avium , commonly known as cherry tree, before and after toasting in cooperage were studied using HPLC-DAD and HPLC-DAD/ESI-MS. Nonflavonoid (16 compounds) and flavonoid (27 compounds) polyphenols were identified, 12 of them in only a tentative way. The nonflavonoids found were lignin constituents, and their pattern is different compared to oak, since they include compounds such as protocatechuic acid and aldehyde, p-coumaric acid, methyl vanillate, methyl syringate, and benzoic acid, but not ellagic acid, and only a small quantity of gallic acid. In seasoned wood we found a great variety of flavonoid compounds which have not been found in oak wood for cooperage, mainly, in addition to the flavan-3-ols (+)-catechin, a B-type procyanidin dimer, and a B-type procyanidin trimer, the flavanones naringenin, isosakuranetin, and eriodictyol and the flavanonols aromadendrin and taxifolin. Seasoned and toasted cherry wood showed different ratios of flavonoid to nonflavonoid compounds, since toasting results in the degradation of flavonoids, and the formation of nonflavonoids from lignin degradation. On the other hand, the absence of hydrolyzable tannins in cherry wood, which are very important in oak wood, is another particular characteristic of this wood that should be taken into account when considering its use in cooperage.
The level of bound hydroxycinnamic acid was determined by spectrophotometry (as total hydroxycinnamic compounds and free-radical-scavenging activity) and reversed-phase high-performance chromatography (RP-HPLC) coupled to mass spectrometry (MS) in barley flours (whole meals and air-classified fractions: coarse fraction and fine fraction). Hydroxycinnamic acids and their derivatives were the main bound phenols in barley flours. A total of 12 different hydroxycinnamic acids were identified and quantified by HPLC/diode array detector (DAD)-MS within 90 min. Ferulic acid (as a simple and glycosylated derivative) was the main phenolic acid in barley flours, representing 89-93% of total hydroxycinnamic acids. The amount of total hydroxycinnamic acid in air-classified coarse fraction was 2 and 3 times higher than those of whole meal and the air-classified fine fraction, respectively. Similarly, the coarse fraction showed higher antioxidant activity (650.03 micromol of TEAC/100 g of flour) compared to whole meal and the fine fraction (388.78 and 320.27 micromol of TEAC/100 g of flour, respectively).
Hydrolysis of bamboo shoot cell walls with Driselase (a fungal enzyme preparation) gave xyloglucan and arabinoxylan oligosaccharides containing ferulic and p-coumaric acids, respectively. The structures of two oligosaccharides containing phenolic acids are here determined to be O-(4-O-trans-feruloyl-alpha-D-xylopyranosyl)-(1----6)-D-glucopy rano se and O-[5-O-(trans-p-coumaroyl(-alpha-L-arabinofuranosyl]-(1----3)-O-be ta-D-xylopyranosyl-(1----4)-D-xylopyranose, on the basis of n.m.r. spectroscopy, methylation analysis, and f.a.b.-m.s. The possible role of phenolic acid substituents in cell-wall architecture is discussed.
Different options of liquid chromatography-mass spectrometry were used to establish the most suitable ion source and conditions to analyse or detect some low-molecular mass phenols, flavan-3-ols, and apply such conditions to a complex sample (wine). Data presented in this work confirm the great utility of atmospheric pressure-ionisation electrospray mass spectrometry coupled to HPLC for analysis of phenolic compounds, under negative mode in the case of low-molecular mass phenols, and under both positive and negative modes in flavan-3-ol compounds. A fragmentor voltage of 60 V could be the most suitable for analysing the compounds under study.
Three antioxidative phenolic compounds, one serotonin derivative and two flavonoids, were isolated from an ethanol extract of Japanese barnyard millet (cv. Kurohie) grains by Sephadex LH-20 chromatography and preparative high-performance liquid chromatography. Their structures were established to be N-(p-coumaroyl)serotonin, luteolin, and tricin on the basis of spectrometric data from (1)H and (13)C and two-dimensional nuclear magnetic resonance techniques, fast atom bombardment mass spectrometry, and Fourier transform infrared spectrophotometry. N-(p-Coumaroyl)serotonin exhibited a strong antioxidant activity almost equivalent to that of butylated hydroxyanisole at the same concentration (w/v). Although the antioxidant activity of luteolin was lower than that of N-(p-coumaroyl)serotonin, it was nearly equal to that of quercetin, whereas the activity of tricin was lower than that of luteolin. All of them were newly isolated from Japanese barnyard millet grains.
Mass spectrometry is an important tool for the identification and structural determination of flavonoid glycosides. The advantages of mass spectrometry are high sensitivity and possibilities of hyphenation with liquid chromatographic methods for the analysis of mixtures of compounds. Different desorption ionization methods allow the analysis of underivatized glycosides. A review of mass spectrometric techniques applied to the identification and structural studies of flavonoid glycosides is presented.
The contents of pnenolic acids and ferulic acid dehydrodimers were quantified by HPLC analysis after alkaline hydrolysis in kernels of 17 rye (Secale cereale L.) varieties grown in one location in Denmark during 1997 and 1998. Significant variations (P < 0.05) with regard to the concentration of the analyzed components were observed among the different rye varieties and also between different harvest years. However, the content of phenolic acids in the analyzed rye varieties was narrow compared to cereals such as wheat and barley. The concentration of ferulic acid, the most abundant phenolic acid ranged from 900 to 1170 microgram g(-1) dry matter. The content in sinapic acid ranged from 70 to 140 microgram g(-1) dry matter, p-coumaric acid ranged from 40 to 70 microgram g(-1) dry matter, and caffeic, p-hydroxybenzoic, protocatechuic, and vanillic acids were all detected in concentrations less than 20 microgram g(-1) dry matter. The most abundant ferulic acid dehydrodimer 8-O-4 -DiFA was quantified in concentrations from 130 to 200 microgram g(-1) dry matter followed by 8,5 -DiFA benzofuran form (50-100 microgram g(-1) dry matter), 5,5 -DiFA (40-70 microgram g(-1) dry matter), and 8,5 -DiFA (20-40 microgram g(-1) dry matter).
Rice is a staple diet in Asia, where the incidence of breast and colon cancer is markedly below that in the Western world. We investigated potential colon and breast tumor-suppressive properties of rice, testing the hypothesis that rice contains phenols that interfere with the proliferation or colony-forming ability of breast or colon cells. Brown rice, its white milled counterpart, and bran from brown rice were boiled and extracted with ethyl acetate. The extracts were analyzed by high pressure liquid chromatography-mass spectrometry. Eight phenols, protocatechuic acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid, vanillic acid, methoxycinnamic acid, and tricin, were identified in the extracts of bran and intact brown rice. These extracts were separated into nine fractions by column chromatography. The effect of bran extract and its fractions at 100 microg/ml on cell viability and colony-forming ability of human-derived breast and colon cell lines was assessed. Bran extract decreased numbers of viable MDA MB 468 and HBL 100 breast cells and colon-derived SW 480 and human colonic epithelial cells as judged by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4 -sulfophenyl)-2H-tetrazolium assay. It also reduced colony formation of SW 480 colon and MDA MB 468 breast cells. Of the eight phenols identified in the brown rice bran, when applied at 50 microM, caffeic acid decreased numbers of all cell types except HBL 100. Tricin, ferulic acid, and methoxycinnamic acid interfered with cell viability in one or more cell lines. Tricin (50 microM) and the other phenols (200 microM) inhibited colony formation of SW 480 cells. Clonogenicity of MDA MB 468 cells was inhibited by caffeic acid, ferulic acid, and tricin (50 microM). Tricin was the most potent anticlonogenic of the compounds with IC50s of 16 microM in the SW 480 colon cells and 0.6 microM in the MDA MB 468 breast cells. The results suggest that: (a) brown rice and bran contain compounds with putative cancer chemopreventive properties; (b) certain phenols contained in brown rice bran, e.g., tricin, may be associated with this activity; and (c) these phenols are present at much lower levels in white than in brown rice. Thus, the consumption of rice bran or brown rice instead of milled white rice may be advantageous with respect to cancer prevention.
Cross-linking of xylans and lignin by ferulates was investigated with primary maize walls acylated with 2% ferulate and with ferulate ethyl esters. Peroxidase-mediated coupling of wall ferulate and ethyl ferulate yielded mostly 8-coupled products, including three new dehydrodimers. Significant quantities of 5-5-coupled diferulate formed only within walls, suggesting that matrix effects influence dimer formation. Over 60% of wall ferulate dimerized upon H2O2 addition, suggesting that xylan feruloylation is highly regulated during wall biosynthesis to permit extensive dimer formation at the onset of lignification. During lignification, ferulate and 5-5-coupled diferulate copolymerized more rapidly and formed fewer ether-linked structures with coniferyl alcohol than 8-5-, 8-O-4-, and 8-8-coupled diferulates. The potential incorporation of most ferulates and diferulates into lignin exceeded 90%. As a result, xylans become extensively cross-linked by ferulate dimerization and incorporation to lignin, but only a small and variable proportion of these cross-links is measurable by solvolysis of lignified walls.
Diferulic acids are potent antioxidants and are abundant structural components of plant cell walls, especially in cereal brans. As such, they are part of many human and animal diets and may contribute to the beneficial effect of cereal brans on health. However, these phenolics are ester-linked to cell wall polysaccharides and cannot be absorbed in this form. This study provides the first evidence that diferulic acids can be absorbed via the gastrointestinal tract. The 5-5-, 8-O-4-, and 8-5-diferulic acids were identified in the plasma of rats after oral dosing with a mixture of the three acids in oil. Our study also reveals that human and rat colonic microflora contain esterase activity able to release 5-5-, 8-O-4-, and 8-5-diferulic acids from model compounds and dietary cereal brans, hence providing a mechanism for release of dietary diferulates prior to absorption of the free acids. In addition, cell-free extracts from human and rat small intestine mucosa exhibited esterase activity towards diferulate esters. Hence, we have shown that esterified diferulates can be released from cereal brans by intestinal enzymes, and that free diferulic acids can be absorbed and enter the circulatory system. Our results suggest that the phenolic antioxidant diferulic acids are bioavailable.
Hydroxycinnamic acid content and ferulic acid dehydrodimer content were determined in 11 barley varieties after alkaline hydrolysis. Ferulic acid (FA) was the most abundant hydroxycinnamate with concentrations ranging from 359 to 624 microg/g dry weight. p-Coumaric acid (PCA) levels ranged from 79 to 260 microg/g dry weight, and caffeic acid was present at concentrations of <19 microg/g dry weight. Among the ferulic acid dehydrodimers that were identified, 8-O-4'-diFA was the most abundant (73-118 microg/g dry weight), followed by 5,5'-diFA (26-47 microg/g dry weight), the 8,5'-diFA benzofuran form (22-45 microg/g dry weight), and the 8,5'-diFA open form (10-23 microg/g dry weight). Significant variations (p < 0.05) among the different barley varieties were observed for all the compounds that were quantified. Barley grains were mechanically fractionated into three fractions: F1, fraction consisting mainly of the husk and outer layers; F2, intermediate fraction; and F3, fraction consisting mainly of the endosperm. Fraction F1 contained the highest concentration for ferulic acid (from 77.7 to 82.3% of the total amount in barley grain), p-coumaric acid (from 78.0 to 86.3%), and ferulic acid dehydrodimers (from 79.2 to 86.8%). Lower contents were found in fraction F2, whereas fraction F3 exhibited the lowest percentages (from 1.2 to 1.9% for ferulic acid, from 0.9 to 1.7% for p-coumaric acid, and <0.02% for ferulic acid dehydrodimers). The solid barley residue from the brewing process (brewer's spent grain) was approximately 5-fold richer in ferulic acid, p-coumaric acid, and ferulic acid dehydrodimers than barley grains.
Free and bound phenolic acids were isolated from native and malted finger millet (ragi, Eleusine coracana Indaf-15), and their antioxidant properties were evaluated. Protocatechuic, gallic, and caffeic acids were found to be the major free phenolic acids. A 3-fold decrease was observed in protocatechuic acid content, whereas the decrease was marginal in the case of caffeic acid upon 96 h of malting. However, the contents of other free phenolic acids such as gallic, vanillic, coumaric, and ferulic acids increased. Ferulic, caffeic, and coumaric acids were found to be the major bound phenolic acids, and a 2-fold decrease was observed in their contents upon 96 h of malting. The antioxidant activity of a free phenolic acid mixture was found to be higher compared to that of a bound phenolic acid mixture. An increase in antioxidant activity coefficient was observed in the case of free phenolic acids from 770.0 +/- 7.8 to 1686.0 +/- 16.0, whereas the same was decreased from 570.0 +/- 6.0 to 448.0 +/- 4.5 in bound phenolic acids upon 96 h of malting. Therefore, the antioxidant capacity of phenolic acids changes during the malting of ragi.
Epidemiological studies have shown that consumption of whole grains and grain-based products is associated with reduced risk of chronic diseases. The health benefits of whole grains are attributed in part to their unique phytochemical composition. However, the phytochemical contents in grains have been commonly underestimated in the literature, because bound phytochemicals were not included. This study was designed to investigate the complete phytochemical profiles in free, soluble conjugated, and insoluble bound forms, as well as their antioxidant activities in uncooked whole grains. Corn had the highest total phenolic content (15.55 ± 0.60 μmol of gallic acid equiv/g of grain) of the grains tested, followed by wheat (7.99 ± 0.39 μmol of gallic acid equiv/g of grain), oats (6.53 ± 0.19 μmol of gallic acid equiv/g of grain), and rice (5.56 ± 0.17 μmol of gallic acid equiv/g of grain). The major portion of phenolics in grains existed in the bound form (85% in corn, 75% in oats and wheat, and 62% in rice), although free phenolics were frequently reported in the literature. Ferulic acid was the major phenolic compound in grains tested, with free, soluble-conjugated, and bound ferulic acids present in the ratio 0.1:1:100. Corn had the highest total antioxidant activity (181.42 ± 0.86 μmol of vitamin C equiv/g of grain), followed by wheat (76.70 ± 1.38 μmol of vitamin C equiv/g of grain), oats (74.67 ± 1.49 μmol of vitamin C equiv/g of grain), and rice (55.77 ± 1.62 μmol of vitamin C equiv/g of grain). Bound phytochemicals were the major contributors to the total antioxidant activity: 90% in wheat, 87% in corn, 71% in rice, and 58% in oats. Bound phytochemicals could survive stomach and intestinal digestion to reach the colon. This may partly explain the mechanism of grain consumption in the prevention of colon cancer, other digestive cancers, breast cancer, and prostate cancer, which is supported by epidemiological studies.
Liquid chromatography coupled with ionspray mass spectrometry in the tandem mode (LC/MS/MS) with negative ion detection was used for the identification of a variety of phenolic compounds in a cocoa sample. Gradient elution with water and acetonitrile, both containing 0.1% HCOOH, was used. Standard solutions of 31 phenolic compounds, including benzoic and cinnamic acids and flavonoid compounds, were studied in the negative ion mode using MS/MS product ion scans. At low collisional activation, the deprotonated molecule [M - H](-) was observed for all the compounds studied. For cinnamic and benzoic acids, losses of CO(2) or formation of [M - CH(3)](-*) in the case of methoxylated compounds were observed. However, for flavonol and flavone glycosides, the spectra present both the deprotonated molecule [M - H](-) of the glycoside and the ion corresponding to the deprotonated aglycone [A - H](-). The latter ion is formed by loss of the rhamnose, glucose, galactose or arabinose residue from the glycosides. Different fragmentation patterns were observed in MS/MS experiments for flavone-C-glycosides which showed fragmentation in the sugar part. Fragmentation of aglycones provided characteristic ions for each family of flavonoids. The optimum LC/MS/MS conditions were applied to the characterization of a cocoa sample that had been subjected to an extraction/clean-up procedure which involved chromatography on Sephadex LH20 and thin-layer chromatographic monitoring. In addition to compounds described in the literature, such as epicatechin and catechin, quercetin, isoquercitrin (quercetin-3-O-glucoside) and quercetin-3-O-arabinose, other compounds were identified for the first time in cocoa samples, such as hyperoside (quercetin-3-O-galactoside), naringenin, luteolin, apigenin and some O-glucosides and C-glucosides of these compounds.
Ion trap HPLC-PAD-ESI/MS/MS has been used to study C-glycosyl flavones in quince seeds. Comparative analysis of the ions [(M-H)-60]-, [(M-H)-90]- and [(M-H)-120]- from 6-C- and 8-C-glycosyl flavone isomers, together with their respective retention times, allowed deductions to be made about the nature of the sugar units and the positions of C-glycosylation. Vicenin-2 (6,8-di-C-glucosyl apigenin), lucenin-2 (6,8-di-C-glucosyl luteolin), stellarin-2 (6,8-di-C-glucosyl chrysoeriol), isoschaftoside (6-C-arabinosyl-8-C-glucosyl apigenin), schaftoside (6-C-glucosyl-8-C-arabinosyl apigenin), 6-C-pentosyl-8-C-glucosyl chrysoeriol and 6-C-glucosyl-8-C-pentosyl chrysoeriol were identified in quince seed.
Flavonoids are very common and widespread secondary plant metabolites. They have a wide range of biological and physiological activities and serve as chemotaxonomic marker compounds. Therefore, they have been extensively investigated both in the past and during recent years. The interest in them is still increasing. In the search for new compounds, and also in quality control, there is a need to have reliable methodology for the analysis of flavonoids. Mass spectrometry can make an invaluable contribution because of its high sensitivity, possibilities of coupling with liquid chromatography and the availability of powerful tandem mass spectrometric techniques. A review of currently available mass spectrometric methodology used in the structure elucidation of flavonoids is presented. Sample preparation, liquid chromatographic/mass spectrometric analysis and tandem mass spectrometric procedures for the characterization of flavonoid aglycones, O-glycosides, C-glycosides and acylated glycosides are considered.
The contents of free and total phenolic acids and alk(en)ylresorcinols were analyzed in commercial products of eight grains: oat (Avena sativa), wheat (Triticum spp.), rye (Secale cerale), barley (Hordeum vulgare), buckwheat (Fagopyrum esculentum), millet (Panicum miliaceum), rice (Oryza sativa), and corn (Zea mays). Avenanthramides were determined in three oat products. Free phenolic acids, alk(en)ylresorcinols, and avenanthramides were extracted with methanolic acetic acid, 100% methanol, and 80% methanol, respectively, and quantified by HPLC. The contents of total phenolic acids were quantified by HPLC analysis after alkaline and acid hydrolyses. The highest contents of total phenolic acids were in brans of wheat (4527 mg/kg) and rye (4190 mg/kg) and in whole-grain flours of these grains (1342 and 1366 mg/kg, respectively). In other products, the contents varied from 111 mg/kg (white wheat bread) to 765 mg/kg (whole-grain rye bread). Common phenolic acids found in the grain products were ferulic acid (most abundant), ferulic acid dehydrodimers, sinapic acid, and p-coumaric acid. The grain products were found to contain either none or only low amounts of free phenolic acids. The content of avenanthramides in oat flakes (26-27 mg/kg) was about double that found in oat bran (13 mg/kg). The highest contents of alk(en)ylresorcinols were observed in brans of rye (4108 mg/kg) and wheat (3225 mg/kg). In addition, whole-grain rye products (rye bread, rye flour, and whole-wheat flour) contained considerable levels of alk(en)ylresorcinols (524, 927, and 759 mg/kg, respectively).
Thirty-seven apricot varieties, including four new releases (Rojo Pasión, Murciana, Selene, and Dorada) obtained from different crosses between apricot varieties and three traditional Spanish cultivars (Currot, Mauricio, and Búlida), were separated according to flesh color into four groups: white, yellow, light orange, and orange (mean hue angles in flesh were 88.1, 85.0, 77.6, and 72.4, respectively). Four phenolic compound groups, procyanidins, hydroxycinnamic acid derivatives, flavonols, and anthocyanins, were identified by HPLC-MS/MS and individually quantified using HPLC-DAD. Chlorogenic and neochlorogenic acids, procyanidins B1, B2, and B4, and some procyanidin trimers, quercetin 3-rutinoside, kaempferol 3-rhamnosyl-hexoside and quercetin 3-acetyl-hexoside, cyanidin 3-rutinoside, and 3-glucoside, were detected and quantified in the skin and flesh of the different cultivars. The total phenolics content, quantified as the addition of the individual compounds quantified by HPLC, ranged between 32.6 and 160.0 mg 100 g(-1) of edible tissue. No correlation between the flesh color and the phenolic content of the different cultivars was observed.
Rosa chinensis (Yuejihua) is a well-known ornamental plant, and its flowers are commonly used in traditional Chinese medicine. Methanolic crude extracts of dried R. chinensis flowers were used for simultaneous determination of phenolic constituents by liquid chromatography-mass spectrometry (LC-MS) and matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS). A total of 36 known and unknown phenolics were identified as hydrolyzable tannins, flavonols, and anthocyanins, mainly including gallotannins (mono-, di-, or trigalloylglucopyranosides), ellagitannins, quercetin, quercetin/kaempferol mono- and diglycosides, and cyanidin/pelargonidin diglycosides. MALDI-QIT-TOF MS was applied not only to verify most phenolics isolated and identified by LC-MS but also to tentatively identify two ellagitannins (rugosins B and C) not isolated and unidentified by LC-MS. This study is the first to demonstrate the rapid and successful use of MALDI-QIT-TOF MS and LC-MS to directly and simultaneously identify phenolics in the crude extracts of R. chinensis flowers without any purification. The antioxidant activity of the crude extracts from R. chinensis flowers was also measured with three assay methods. The results showed that the phenolic antioxidants from R. chinensis flowers exhibited very strong radical scavenging effect and antioxidant power. High levels of flavonols and hydrolyzable tannins might be important bioactive principles in the dried R. chinensis flowers.
Two commercial samples of soft (70% Canadian Eastern soft red spring and 30% Canadian Eastern soft white winter) and hard (90% Canadian western hard red spring and 10% Canadian Eastern hard red winter) wheats were used to obtain different milling fractions. Phenolics extracted belonged to free, soluble esters and insoluble-bound fractions. Soluble esters of phenolics and insoluble-bound phenolics were extracted into diethyl ether after alkaline hydrolysis of samples. The content of phenolics was determined using Folin-Ciocalteu's reagent and expressed as ferulic acid equivalents (FAE). The antioxidant activity of phenolic fractions was evaluated using Trolox equivalent antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, reducing power, oxygen radical absorbance capacity, inhibition of oxidation of human low-density lipoprotein cholesterol and DNA, Rancimat, inhibition of photochemilumenescence, and iron(II) chelation activity. The bound phenolic content in the bran fraction was 11.3 +/- 0.13 and 12.2 +/- 0.15 mg FAE/g defatted material for hard and soft wheats, respectively. The corresponding values for flour were 0.33 +/- 0.01 and 0.46 +/- 0.02 mg FAE/g defatted sample. The bound phenolic content of hard and soft whole wheats was 2.1 (+/-0.004 or +/-0.005) mg FAE/g defatted material. The free phenolic content ranged from 0.14 +/- 0.004 to 0.98 +/- 0.05 mg FAE/g defatted milling fractions of hard and soft wheats examined. The contribution of bound phenolics to the total phenolic content was significantly higher than that of free and esterified fractions. In wheat, phenolic compounds were concentrated mainly in the bran tissues. In the numerous in vitro antioxidant assays carried out, the bound phenolic fraction demonstrated a significantly higher antioxidant capacity than free and esterified phenolics. Thus, inclusion of bound phenolics in studies related to quantification and antioxidant activity evaluation of grains and cereals is essential.
Two new dehydrotriferulic acids and two dehydrotetraferulic acids were isolated from saponified maize bran insoluble fiber using size exclusion chromatography on Bio-Beads S-X3 followed by Sephadex LH-20 chromatography and semipreparative phenyl-hexyl reversed phase high-performance liquid chromatography. On the basis of UV spectroscopy, mass spectrometry, and one- and two-dimensional NMR experiments, the structures were identified as 8-5(noncyclic)/5-5-dehydrotriferulic acid, 8-8(tetrahydrofuran)/5-5-dehydrotriferulic acid, and 4-O-8/5-5/8-O-4-dehydrotetraferulic acid. The second tetramer was tentatively identified as 4-O-8/5-5/8-5(noncyclic)-dehydrotetraferulic acid. Compounds containing an 8-5(noncyclic)-coupled dimeric unit probably do not exist in planta but are formed from their phenylcoumaran precursors containing an 8-5(cyclic)-coupled dimeric unit during saponification. The presented dehydrotrimers are the first dehydrotriferulates that do not contain an 8-O-4-coupled dimeric unit. The ferulate dehydrotetramers that are reported for the first time are presumed, like the dimers and trimers, to cross-link polysaccharides in the plant. Because both tetramers contain a 5-5/8-O-4-dehydrotriferulate moiety, the predominant dehydrotrimer in maize bran, it is not possible to deduce whether tetramers are formed by coupling of a fourth unit to a preformed dehydrotriferulate or by 5-5-coupling of preformed 8-O-4- and 8-5-dehydrodiferulates. Nevertheless, such compounds document expanded roles for ferulates in cross-linking polysaccharides in plant cell walls.
Twenty-eight polyphenols (11 flavonoid derivatives and 17 hydroxycinnamic acid derivatives) were detected in different cultivars of the Chinese cabbage pak choi ( Brassica campestris L. ssp. chinensis var. communis) by HPLC-DAD-ESI-MS(n). Kaempferol was found to be the major flavonoid in pak choi, glycosylated and acylated with different compounds. Smaller amounts of isorhamnetin were also detected. A structural determination was carried out by (1)H and (13)C NMR spectroscopy for the main compound, kaempferol-3-O-hydroxyferuloylsophoroside-7-O-glucoside, for the first time. Hydroxycinnamic acid derivatives were identified as different esters of quinic acid, glycosides, and malic acid. The latter ones are described for the first time in cabbages. The content of polyphenols was determined in 11 cultivars of pak choi, with higher concentrations present in the leaf blade than in the leaf stem. Hydroxycinnamic acid esters, particularly malic acid derivatives, are present in both the leaf blade and leaf stem, whereas flavonoid levels were determined only in the leaf blade.