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Background: Rice is the third-most-produced crop in the world after corn and sugarcane, and due to its widespread production, its byproduct, rice bran, is widely available. One option to add value to this agricultural waste is by utilizing the potential phytochemicals in rice bran oil (RBO). Rice bran oil contains vital chemicals with medicinal and nutritional benefits. This paper examines the numerous ways that rice bran oil is extracted, the various phytochemicals that are present, as well as their potential for use in nutrition and medicine. Method: A review of literatures released from 1996 to 2023 was done, with just one more item of literature from 1973. The search was performed in various online platforms such as Google Scholar, PubMed, Science Direct, Springer, Research4Life, Web of Science, SciFinder, Science Open etc. The more recent literatures were given more consideration, and the older literatures were only taken into account when they were absolutely essential in light of the subject at hand. Results: Literature survey has revealed that the essential phytochemical components of RBO includes phenolic acids, flavonoids, γ-oryzanol and ferulic acids and vitamin E which constitutes tocopherols and tocotrienols as well as other unique fatty acids. Numerous therapeutical potentials, including antioxidant, anti-inflammatory, antidiabetic, and anticancer activities have been evidenced, thanks to these significant phytochemical ingredients. Additionally, numerous nutritional potentials of RBO have been researched and reported. Conclusions: This review consolidates information on the developments in RBO extraction techniques, phytochemical components, and their nutritional and medicinal benefits. Also included are the approach towards processing of rice bran. Considering the abundance and potential of this agrowaste, the use of RBO based phytochemicals for nutritional and therapeutic purpose is worthy pursuing further.
Rice bran is a rather underutilized by-product of the rice industry that nowadays is far from being valorized. In this study, the lipidomic profile of bran of the Italian rice variety, Roma, has been evaluated through ultra performance liquid chromatography—tandem mass spectrometry. Crude lipid extracts were obtained from rice bran treated with different green solvents (1-butanol, ethanol and methyl tert-butyl ether/methanol mixture) in combination with an ultrasonic pre-treatment, and then compared with extracts obtained with standard solvents (chloroform/methanol mixture). Lipid yield, number and type of lipids and composition of prevalent lipid classes extracted were evaluated in order to provide an exhaustive lipid profile of the rice bran and to identify the most efficient green solvent for solid–liquid extractions. Twelve different lipid classes and a maximum of 276 lipids were identified. Ethanol and methyl tert-butyl ether/methanol solvents provided higher lipid extraction yields, the former being the most effective solvent for the extraction of triglycerides and N-acylethanolamines and the latter the most effective for the extraction of diglycerides, phospholipids and ceramides at 4 °C. Moreover, extraction with ethanol at 20 °C gave similar results as at 4 °C in terms of lipid yield and for most of the classes of lipids extracted. Taken together, our results indicate ethanol and methyl tert-butyl ether/methanol as excellent solvents for lipid extraction from rice bran, with the aim to further valorize this food by-product in the perspective of a circular economy.
Rice bran is a nutrient-rich and resource-dense byproduct of rice milling. The primary cause of rice bran utilization limitation is oxidative deterioration and inadequate storage facilities. Improving stability to extend the shelf-life of rice bran has thus become an utmost necessity. This study aimed to stabilize raw fresh rice bran (RB) by using dry heat methods at 120 °C (233, 143, and 88 min) and 130 °C (86, 66, and 50 min). The results indicated that after dry heat pretreatment, peroxidase levels were at 90%, and the storage stability of dry-heat-stabilized RB was better. However, with an increase in treatment temperature and time, the peroxidase activity improved while the lipase activity decreased to a certain extent without significant changes. The total saturated and unsaturated fatty acids were significantly unchanged during storage, while oleic/linoleic acid increased substantially by 1% at 120 °C for 88 min. The increase in treatment time and temperature was beneficial in controlling the fatty acid values. However, extended treatment time caused an increase in the peroxide value and MDA. The essential and non-essential amino acid ratios, which evaluate a protein’s nutritional value, remained relatively stable. The essential subunit of rice bran protein was not affected by the temperature and time of dry heat treatment and storage time.
The processing technique is one of the key factors affecting the quality of camellia oil. In this study, camellia oils were obtained using four different processing techniques (cold-pressed, roast-pressed, fresh-pressed, and refined), and their triacylglycerols (TAGs) profile, bioactive compound (tocopherols, sterols, squalene, and polyphenols) level, oxidative stability, and volatile compounds were analyzed and compared. To further identify characteristic components in four camellia oil products, the TAG profile was analyzed using UPLC-QTOF-MSE. Five characteristic markers were identified, including OOO (m/z 902.8151), POL (m/z 874.7850), SOO (m/z 904.8296), PPL (m/z 848.7693), PPS (m/z 852.7987). Regarding the bioactive compound level and antioxidant capacity, the fresh-pressed technique provided higher α-tocopherols (143.15 mg/kg), β-sitosterol (93.20 mg/kg), squalene (102.08 mg/kg), and polyphenols (35.38 mg/kg) and showed stronger overall oxidation stability and antioxidant capacity. Moreover, a total of 65 volatile compounds were detected and identified in four camellia oil products, namely esters (23), aldehydes (19), acids (8), hydrocarbons (3), ketones (3), and others (9), among which pressed oil was dominated by aldehydes, acid, and esters, while refined oil had few aroma components. This study provided a comprehensive comparative perspective for revealing the significant influence of the processing technique on the camellia oil quality and its significance for producing camellia oil of high quality and with high nutritional value.
The main aim of this study is to evaluate and compare the physicochemical properties, chemical composition, and in vitro antioxidant activities of rice bran oil (RBO) from five most popular japonica rice (Oryza sativa L.) varieties planted in China. It was found that the AV and PV of RBOs were 0.45–1.18 mg KOH/g and 0.72–1.73 mmol/kg, individually. The L*, a*, and b* values of RBOs were 24.18–26.70, 1.84–2.54, and 6.35–9.01, respectively. RBOs were rich in linoleic acid (38.63–43.50%), oleic acid (34.23–41.20%), and palmitic acid (16.26–18.93%). POL + SLL (17.44–19.29%), OLL (16.06–17.67%), OOL (13.79–17.79%), and PLL (11.70–14.79%) were the predominant triacylglycerols of RBOs. RBO from different rice varieties contained abundant bioactive constituents such as tocopherols and tocotrienols (948.59–1461.90 mg/kg), squalene (2055.65–4456.79 mg/kg), γ-oryzanol (19391.15–30024.09 mg/kg), phytosterols (10632.74–13948.17 mg/kg), and polyphenols (127.55–358.84 mg/kg). Pigments such as carotenoids and chlorophylls varied from 6.47 to 14.29 mg/kg and 0.79 to 12.96 mg/kg. The DPPH, ABTS, FRAP, and ORAC value were 837.41–1055.64, 1592.38–2106.47, 244.27–557.13, and 170.16–1776.41 µmol TE/100 g, respectively. This work could provide useful information to consumers for choosing suitable vegetable oils based on their health needs.
Rice is one of the most important crops throughout the world, as it contributes toward satisfying the food demand of much of the global population. It is well known that rice production generates a considerable number of by-products, among which rice bran deserves particular attention. This by-product is exceptionally rich in nutrients, since it contains a wide spectrum of macronutrients (proteins, fats, carbohydrates) as well as dietary fibers and bioactive compounds. However, rice bran is usually wasted or just used for the production of low-cost products. The lipidic fraction of rice bran contains an unsaponifiable fraction that is rich in such functional components as tocopherols, γ-oryzanol, tocotrienols, and phytosterols. This lipidic fraction can be extracted to obtain rice bran oil (RBO), a high value-added product with unique health properties as a result of its high concentration in γ-oryzanol, a powerful antioxidant mixture of bioactive molecules. Conventional extraction methods employ hexane as the solvent, but these methods suffer from some drawbacks linked to the toxicity of hexane for humans and the environment. The aim of the review presented herein is to point out the new green technologies currently applied for the extraction of RBO, by highlighting reliable alternatives to conventional solvent extraction methods that are in line with the twelve principles of green chemistry and a circular economy.
Rice bran is an invaluable by-product of paddy processing industry. It is rich in minerals, protein, lipids, and crude fiber. In addition, it also possesses compounds with anti-oxidant, anti-allergic, anti-diabetic, and anti-cancer properties. It forms a basis for the extraction of rice bran oil and preparation of various functional foods with health benefits and potential to prevent chronic health issues. Nevertheless, the rapid deterioration of bran upon storage acts as a major limitation in exploiting the full potential of rice bran. In this review, we have discussed three strategies to address rapid rancidity of rice bran and enhance its shelf life and storability vis-a-vis emphasizing the importance of rice bran in terms of its nutritional composition. One strategy is through exploitation of the null mutations in the genes governing lipases and lipoxygenases leading to nonfunctional enzymes (enzyme deficient approach), another strategy is through reducing the PUFA content that is more prone to oxidation (substrate deficient approach) and a third strategy is through enhancing the antioxidant content that effectively terminate the lipid peroxidation by donating the hydrogen atom.
Vegetable oils are a rich source of bioactive substances. The non-saponifiable substances that accompany lipids include tocopherols, sterols, squalene. The aim of this study was to develop a new method for the simultaneous determination of tocopherols (α-, (β+γ)-, and δ-tocopherols), phytosterols (β-sitosterol and stigmasterol), and squalene in vegetable oils. Chromatographic (HPLC) separation was performed within 37 min with a mobile phase of 98:2 (v/v) methanol–water and isopropanol at a flow rate of 1.0 mL min⁻¹ at 30 °C. Detection and quantification were performed at 210 nm. The results showed that the best source of total tocopherols is soybean oil (39.9 mg/100 g), followed by corn oil (36.06 mg/100 g), olive oil (29.42 mg/100 g), and camellia oil (17.72 mg/100 g). The content of plant sterols ranged from 94.96 mg/100 g in camellia oil to 314.15 mg/100 g in corn oil. Soybean oil and olive oil contained 164.14 and 127.80 mg/100 g, respectively. The content of squalene in corn oil was a mean of 256.84 mg/100 g, while there was only a weakly significant difference between camellia oil (159.76 mg/100 g) and olive oil (162.41 mg/100 g). The content of squalene in soybean oil was 92.07 mg/100 g. The results indicated that the method could be used for the simultaneous analysis of phytosterols, tocopherols, and squalene in vegetable oils.
One of the major challenges in the upgrading of high-acid rice bran oil (RBO) is to efficiently reduce the amount of free fatty acids. Here we report a novel method for upgrading high-acid RBO using ethanol as a novel acyl acceptor in combination with a highly selective lipase from Malassezia globosa (SMG1-F278N). This process enabled an unprecedented deacidification efficiency of up to 99.80% in a short time (6 h); the immobilized SMG1-F278N used in deacidification exhibited excellent operational stability and could be used for at least 10 consecutive batches without detectable loss in activity. Scale-up was performed under optimized conditions to verify the applicability of this process, and low-acid (0.08%) RBO with a high level of γ-oryzanol (27.8 g/kg) and γ-oryzanol accumulation fold (1.5) was obtained after molecular distillation at lower temperature (120 °C). Overall, we report a simplified and efficient procedure for the production of edible RBO from high-acid RBO.
In present study, phospholipase A1 (PLA1) and phospholipase C (PLC) were applied in eight varieties of crude oils. The degumming efficiency, oil yield and diacylglycerols (DAG) content after different kinds of treatments were investigated. Though the citric acid-PLC-PLA1 degumming process could efficiently reduce the phosphorus content and maintain the maximal oil yield of most oil samples. Still, specific enzymatic degumming process could be selected according to the quality of different crude oils. For example, to oil samples with low contents of non-hydratable phospholipids (NHPs) and initial phosphorus, PLA1 degumming without acid pretreatment was the most efficient way. To oil samples with low content of NHPs and high content of initial phosphorus, PLC degumming with acid pretreatment could satisfy the requirement for physical refining while increase the oil yield. To oil samples with high content of NHPs and low content of initial phosphorus, the PLA1 degumming with acid pretreatment was the best choice. In further industrial application, flexible degumming process could be applied in accordance with the specific oil characteristics to make the process more efficient and more eco-friendly.
Phospholipids have the characteristics of excellent biocompatibility and a especial amphiphilicity. These unique properties make phospholipids most appropriate to be employed as important pharmaceutical excipients and they have a very wide range of applications in drug delivery systems. The aim of this review is to summarize phospholipids and some of their related applications in drug delivery systems, and highlight the relationship between the properties and applications, and the effect of the species of phospholipids on the efficiency of drug delivery. We refer to some relevant literatures, starting from the structures, main sources and properties of phospholipids to introduce their applications in drug delivery systems. The present article focuses on introducing five types of carriers based on phospholipids, including liposomes, intravenous lipid emulsions, micelles, drug-phospholipids complexes and cochleates.
Rice (Oryza sativa) is the most important staple food for a large part of the world's human population, especially in East and South Asia, the Middle East, Latin America, and the West Indies. It provides more than one fifth of the calories consumed worldwide by the human. It is the second leading cereal crop and staple food of half of the world's population. It is grown in at least 114 countries with global production of 645 million tons; share of Asian farmers is about 90% of the total produce. Rice bran, brown outer layer of rice kernel, is mainly composed of pericarp, aleurone, subaleurone layer, and germ. It contains appreciable quantities of nutrients like protein, fat, and dietary fiber. Furthermore, it contains substantial amount of minerals like K, Ca, Mg, and Fe. Presence of antioxidants like tocopherols, tocotrienols, and γ-oryzanol also brighten prospects of rice bran utilization for humans as functional ingredient to mitigate the life-threatening disorders. Moreover, in the developing countries, budding dilemma of food crisis, arising due to lower crop yields and escalating population, needs to utilize each pent of available resources. To provide enough food to all people, there is the holistic approach of using the by-products generated during food processing and preparations. Rice is being processed in well-established industry, but the major apprehension is the utilization of its by-products; rice bran (5-8%) and polishing (2-3%) that are going as waste. Rice processing or milling produces several streams of materials including milled rice, bran, and husk. In developing countries, rice bran is considered as a by-product of the milling process and commonly used in animal feed or discarded as a waste. The potential of producing rice bran at the global level is 29.3 million tons annually, whereas the share of Pakistan is worked out to be 0.5 million tons. In present paper, attempt has been made to highlight the significance of these valuable but neglected ingredients under various headings.
The digestion and metabolism of lipids continues to generate considerable scientific interest, with food emulsions increasingly being seen as a mechanism by which lipid uptake may be controlled. Scientific advancement in this field is partly being driven by the ongoing need to address the obesity crisis, for which the enhancement of satiety and/or reduction of energy intake is seen as a positive solution in achieving more effective weight management. Yet the ability to regulate lipid uptake is also seen as beneficial in other areas, such as improved nutrition for the young and/or elderly and in cardiovascular protection.
Abstract
BACKGROUND:
Phospholipase A (PLA) is an important group of enzymes responsible for phospholipid hydrolysis in lipid signaling. PLAs have been implicated in abiotic stress signaling and developmental events in various plants species. Genome-wide analysis of PLA superfamily has been carried out in dicot plant Arabidopsis. A comprehensive genome-wide analysis of PLAs has not been presented yet in crop plant rice.
METHODOLOGY/PRINCIPAL FINDINGS:
A comprehensive bioinformatics analysis identified a total of 31 PLA encoding genes in the rice genome, which are divided into three classes; phospholipase A(1) (PLA(1)), patatin like phospholipases (pPLA) and low molecular weight secretory phospholipase A(2) (sPLA(2)) based on their sequences and phylogeny. A subset of 10 rice PLAs exhibited chromosomal duplication, emphasizing the role of duplication in the expansion of this gene family in rice. Microarray expression profiling revealed a number of PLA members expressing differentially and significantly under abiotic stresses and reproductive development. Comparative expression analysis with Arabidopsis PLAs revealed a high degree of functional conservation between the orthologs in two plant species, which also indicated the vital role of PLAs in stress signaling and plant development across different plant species. Moreover, sub-cellular localization of a few candidates suggests their differential localization and functional role in the lipid signaling.
CONCLUSION/SIGNIFICANCE:
The comprehensive analysis and expression profiling would provide a critical platform for the functional characterization of the candidate PLA genes in crop plants
Brown rice exhibits higher nutritional value and attracts more and more attentions; however, the change in phospholipid molecular species in brown rice during aging is poorly understood. In this study, shotgun lipidomics was employed to investigate the changes in phospholipid molecular species in four brown rice varieties (two japonica rice and two indica rice) during accelerated aging. A total of 64 phospholipid molecular species were identified, and most of them were rich in polyunsaturated fatty acids. For japonica rice, phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylglycerol (PG) gradually decreased during accelerated aging. However, the content of PC, PE, and PG in indica rice showed no difference during accelerated aging. Significantly different phospholipid molecular species from four brown rice were screened during accelerated aging. Based on these significantly different phospholipids, the metabolic pathways including glycerophospholipid metabolism and linoleic acid metabolism during accelerated aging were depicted. The findings from this study could be helpful in explaining the impact of accelerated aging on phospholipids of brown rice, and offer an understanding on relationships between phospholipids degradation and brown rice deterioration.
Enzymatic degumming is an essential refining process to improve oil quality. In this study, a monoacylglycerol lipase GMGL was derived from marine Geobacillus sp, and was found that not only took monoacylglycerol (MAG) as substrate, but also had activity toward lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE) and glycerolphosphatidylcholine. Binding free energy showed LPC and LPE could bind with the enzyme stably as MAG. It presented great potential in the field of enzymatic degumming. The phosphorus content in crude soybean oil decreased from 680.50 to 2.01 mg/kg and the yield of oil reached to 98.80% after treating with phospholipase A1 (Lecitase® Ultra) combined with lipase GMGL. An ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed to identify 21 differential phospholipids between crude soybean oil and enzymatic treatment. This work might shed some light on understanding the catalytic mechanism of monoacylglycerol lipase and provide an effective strategy for enzymatic degumming.
γ-oryzanol has been well studied for its hypolipidemic, antidiabetic, antiallergic, and anti-inflammatory abilities. However, its ability against lipid oxidation has not been thoroughly explored. The present study examined the effects of γ-oryzanol against canola oil oxidation under Chinese cooking temperatures compared with that of butylated hydroxytoluene (BHT). Changes of oxygen consumption and fatty acids of canola oil with addition of 2–8 mg/g γ-oryzanol were conducted under 60, 90, 120, and 180 °C, respectively. Results showed although γ-oryzanol was not as effective as BHT against lipid oxidation of heated canola oil, it showed an inhibitory effect on the headspace oxygen consumption dose-dependently. Besides, γ-oryzanol significantly prevented the decrease of total polyunsaturated fatty acids in canola oil heated at 60–120 °C, while such effect was not observed in canola oil heated at 180 °C. β-sitosteryl ferulate, one of the major components constituting γ-oryzanol, degraded faster than cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, and campesteryl ferulate at all treatment conditions. In conclusion, γ-oryzanol might have a potential application against lipid oxidation in foods as a functional antioxidant.
Although hazelnut oil is is nutritious, it is easily oxidized during storage. Thus far, changes in lipids during storage have not been comprehensively analyzed. Here, we used ultra-high liquid chromatography tandem quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) to dynamically monitor the lipid composition of hazelnut oil during accelerated storage for 24 d. A total of 10 subclasses of 103 lipids were identified. After 24 d, the content of triacylglycerol, diacylglycerol, phosphatidic acid, phosphatidylethanolamine, phosphatidylethanol, ceramide, and total lipids decreased significantly (P < 0.05). A total of 51 significantly different lipids were screened (Variable Importance in Projection > 1, P < 0.05), and these lipids could be used as biomarkers to distinguish fresh and oxidized hazelnut oil. We also detected seven most important pathways by bioinformatics analysis to explore the mechanism underlying changes. Our results provide useful information for future applications of hazelnut oil and provide new insight into edible oil oxidation.
Rice bran protein (RBP) was prepared from rice bran (RB) under different storage periods (0, 1, 5, 7, 10 d), and isolated RBP was used to prepare protein emulsion. The RB crude oil acid value, the RBP oxidation degree, the RBP emulsion stability, and the interface-adsorbed protein and interface-unabsorbed protein structure of RBP emulsion were evaluated. With the RB storage time prolonged, the acid value of RB crude oil and the RBP carbonyl content gradually increased, indicated the occurrence of RB rancidity and RBP oxidation. Furthermore, RBP oxidation led to significant changes in the RBP emulsion stability. Moderate oxidation (RB stored for 1 d) could increase the stability of RBP emulsion, while excessive oxidation (RB stored for 5–10 d) could weaken the emulsion stability. In addition, the increasing RB storage time changed the flexibility and aggregation degree of the adsorbed protein and unabsorbed protein on the emulsion interface. The correlation analysis showed that the stability of the protein emulsion was highly correlated (P < 0.01) with the flexibility of interface-adsorbed protein, but showed little correlation with the flexibility of the unabsorbed protein at the interface. By regulating the oxidation degree of RPB to improve the emulsion stability, this research can provide a theoretical reference for promoting the stability of protein emulsions, and enlarging their applications in food systems.
Normal brain functioning involves the interaction of interconnected molecular and cellular activities, which appear to alter normal to abnormal brain functioning when worsened, contributing to the emergence of neurological disorders. There are currently millions of people who are living with brain disorders globally and this will rise if suitable prevention strategies are not explored. Nutraceutical intended to treat numerous health goals with little adverse effect possible together can be more beneficial than pharmaceutical monotherapy for fostering balanced brain functioning. Nutraceutical provides a specific composition of effective macronutrients and micronutrients that are difficult to synthesize in the laboratory. Numerous elements of rice fibers in rice bran are characterized as natural anti-oxidant and having potential anti-inflammatory activity. The rice bran captures interest among the researchers as it is widespread, affordable, and rich in nutrients including protein, fat, carbohydrates, bioactive components, and dietary fiber. This review covers the neuroprotective multiplicity of rice bran and its constituents to deter pathological conditions of the brain and to facilitate balanced brain functioning at the same time.
The bran fraction of rice grains is used for extracting nutritious edible oil known as rice bran oil (RBO). In spite of its nutritional quality, bran lipids have a lower shelf-life due to the hydrolytic and oxidative rancidity. During the rice grain milling, endogenous lipases come in contact with storage lipids or triacylglycerols (TAGs) in the ruptured bran layers. The fatty acid ester bonds in the TAGs are hydrolyzed by the lipases causing the release of free fatty acids (FFAs) and glycerol. Further oxidation of these FFAs, especially the linoleic acid (18:2) are further oxidized by the action of lipoxygenases (LOXs). This reaction produced conjugated hydroperoxides of 18:2, which decompose and form secondary oxidation products responsible for the strong undesirable stale off-flavors. The outcome is a deterioration of bran lipids and significant loss of TAGs during RBO refining process. Therefore, this review aims to provide a holistic view on the current understanding of the catalog of genes and the underlying molecular mechanisms involved in triggering bran lipid rancidity. Generated knowledge about the individual genes will be crucial for developing advanced genome editing strategies to regulate rice bran lipid quality and stability.
Rice is one of major staple food worldwide; however, lipid profile of rice and changes during storage remain unclear. Herein, an UPLC-Q-Exactive Orbitrap/MS method was applied for comprehensive lipidomics analysis of rice during storage. A total of 21 subclasses of 277 lipids including fatty acid (36 species), (O-acyl)-1-hydroxy fatty acid (6 species), diglyceride (16 species), triglyceride (89 species), lysophosphatidylcholine (4 species), phosphatidylcholine (14 species), phosphatidylethanolamine (28 species), phosphatidylglycerol (6 species), phosphatidylinositol (11species), cardiolipin (4 species), ceramide (8 species), hexosylceramide (20 species), dihexosylceramide (2 species), trihexosylceramide (1 species), sitosterol ester (1species), acyl hexosyl campesterol ester (5 species), acyl hexosyl sitosterol ester (6 species), digalactosyldiacylglycerol (6 species), monogalactosyldiacylglycerol (9 species), monogalactosylmonoacylglycerol (2 species), and sulfoquinovosyldiacylglycerol (3 species), were first identified in rice during storage. In addition, ceramide, fatty acid, (O-acyl)-1-hydroxy fatty acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, lysophosphatidylcholine, and diglyceride were quantified. Furthermore, statistical analysis of all lipids was performed based on MetaboAnalyst software. The results showed that 22 lipids were significantly different between fresh and stored (360 and 540 days storage) rice demonstrating that lipid composition changed during storage. These different lipids involved 11 metabolic pathways, of which linoleic acid metabolism, glycerophospholipid metabolism, and cutin, suberine and wax biosynthesis were the most relevant. Our study provides useful information for lipidomics profile of rice during storage.
Rice (Oryza sativa) bran oil (RBO) is unique among edible vegetable oils because of its unique fatty acid composition, phenolic compounds (γ-oryzanol, ferulic acids) and vitamin E (tocopherols and tocotrienols). It has become a great choice of cooking oil because of its very high burning point, neutral taste,and delicate flavour. Non-conventional methods of RBO extraction are more efficient and environmentally friendly than conventional extraction methods. Advances in RBO extraction using innovative extraction strategies like super/sub critical CO2, microwave-assisted, subcritical H2O, enzyme-assisted aqueous, and ultrasound-assisted aqueous extraction method have proven to significantly improve the yields along with improved nutritional profile of RBO. The composition and strategies for stabilization of RBO is well discussed. The constituents present in the RBO contributes toantioxidative, anti-inflammatory, antimicrobial, anti-diabetic, and anti-cancerous properties to RBO. Thishas helped RBO to become an important substrate for the application in food (cooking oil, milk products, meat products) and non-food industries (polymers, lubricants, biofuel, structural lipids, cosmetics). This review paper deals with comprehensive information on RBO extraction methods, oil stabilization, existing applications and health benefits.
Storage lipid mobilization by lipases and lipoxygenases (LOXs) in response to developmental cues take place during seed germination. After rice grain milling, the endogenous lipases and LOXs present in the bran fraction come in contact with the storage lipid reserve or triacylglycerol (TAG). Lipases catalyze the hydrolysis of TAGs to non-esterified fatty acids (NEFAs) and glycerol. The NEFAs, especially linoleic acid (18:2) produced, are further subjected to oxidative rancidity via peroxidation reaction catalyzed by LOXs. This results in the production of conjugated hydroperoxides of 18:2 that influence the stale off-flavors in rice bran lipids. The aim of this study is to understand how lipid mobilization and expression of lipase and LOX genes occur in the bran of germinating rice grains (Oryza sativa var. Pusa Basmati 1). Our results show that the primary source of storage lipids in bran is TAG, and its mobilization starts at 4 days after imbibition (4 DAI). Using publically available RNA-seq data and phylogeny analyses, we selected a total of 18 lipase and 16 LOX genes in rice for their expression profiles during onset of lipid mobilization. Gene expression analyses revealed OsLip1, OsLip9, and OsLip13; and OsLOX3 and OsLOX14 as the predominantly expressed genes in bran of germinating rice grains. This study explores two important events in the germinating rice grains, namely, mobilization of storage lipids and expression pattern of lipase and LOX genes. The information generated in this study can be used to efficiently manipulate the genes to enhance the shelf-stability of bran lipid reserve.
The drastic rise in global warming and the fossil fuel consumption have resulted in destruction of the ecological balance, reduction of the environmental quality, and demotion of the sustainable development. The utilization of biofuels have been paid much attention to by researchers and policy makers due to its benefits and indisputable contributions to protect the living environment. Free fatty acid-rich rice bran oil which is unsuitable for food purposes could be a good candidate for biofuel production. Accordingly, rice bran oil-based biofuels (straight oil and its biodiesel) as promising alternative fuels to petrodiesel were reviewed in this article from the sources, components, and physicochemical perspectives. In addition, biodiesel production from rice bran oil using various methods and catalysts was thoroughly detailed. The oxidative stability of rice bran biodiesel as a function of the storage time was also discussed. The application of rice bran oil-based biofuels to diesel engines was completely analyzed and critically discussed based on engine performance, combustion, and emissions characteristics. The effects of using rice bran oil-based biofuels on the lubricating oil degradation, deposit formation, wear, and sound intensity of diesel engines were explained in detail. Finally, the economic aspects of using rice bran oil and its biodiesel as fuels were also assessed. As a conclusion, the blend containing 20% rice bran oil biodiesel and 80% petrodiesel fuel, both in volume, could be the most effective composition considering the techno-economic aspects of diesel engines; meanwhile the remaining blends appeared to be improper for the existing diesel engines.
The effects of enzymatic free fatty acid reduction process (EFFARP) on the composition and phytochemicals of dewaxed and degummed rice bran oil (DDRBO) were investigated and compared with the effects observed using internal acyl acceptors. The acid value of DDRBO was effectively decreased from 16.99 mg KOH/g to approximately 0.36 mg KOH/g by EFFARP. EFFARP significantly decreased the moisture content and peroxide value of DDRBO and increased the induction period. The Sn-2 fatty acid comoposition of DDRBO after EFFARP was very reaching the total fatty acid composition. EFFARP significantly increased the triacylglycerol content compared to the control, while the oryzanol content was not obviously affected. The contents of free sterol, and total tocopherol and tocotrienol were increased slightly by EFFARP compared to the control. When conducted under vacuum with added nitrogen, EFFARP shows great application potential in the edible oil industry.
Rice bran rancidity may affect rice bran protein through protein oxidation. However, little is known about the relationship between rice bran rancidity and rice bran protein oxidation. The effects of rice bran rancidity on the oxidation extent and structural characteristics of rice bran protein were investigated. As storage time of rice bran increased, the acid value, peroxide value, and value of thiobarbituric acid reactive substances in crude rice bran oil increased from 4.31 mg KOH/g, 2.84 Meq/kg, and 6.22 μg MDA/g to 38.72 mg KOH/g, 15.58 Meq/kg, and 28.99 μg MDA/g, respectively, which indicated that hydrolytic rancidity and oxidative rancidity of rice bran occurred simultaneously. The gradual increase in protein carbonyl and dityrosine content from 2.12 nmol/mg and 88.61 A.U. to 13.8 nmol/mg and 159.37 A.U. was accompanied by a steady decrease in free sulfhydryl content of rice bran protein from 22.6 to 9.6 nmol/mg, which implied that the products of rice bran rancidity induced rice bran protein oxidation. The rice bran protein oxidation subsequently resulted in a loss of the ordered state of secondary structure and the formation of aggregates as well as cross-link, when both disulfide bonds and non-disulfide covalent bonds participated in cross-link formation.
Background: Structured phospholipids are phospholipids with its fatty acid composition modified for the enhancement of physicochemical and nutritional properties. Phospholipids exert stronger biological effects due to its superior bioavailability compared to other lipid forms such as triacylglycerols. Hence, by incorporating functional fatty acids into phospholipid, structured phospholipid could be used as an efficient carrier to increase the absorption of the fatty acid in the body. Scope and approach: This review focuses on the preparation method of structured phospholipid and the effects of certain parameters on the transesterification efficiency. Information on researches conducted on structured phospholipids over the last 20 years have been compiled to provide information on the materials and parameters used. The analysis methods for the fatty acid and phospholipid profile are required to ascertain the efficiency of the transesterification reaction. Furthermore, it is important to understand the functional benefits of structured phospholipid and the methods used in literature to analyse the metabolism of structured phospholipid in in vitro or in vivo models. Key findings and conclusion: Structured phospholipid modified to contain functional fatty acids have the potential to be employed as novel treatments for metabolic diseases and other medical applications to improve body function and reduce risk of certain diseases. Lipidomics advancement could help to evaluate the treatment of metabolic diseases and access the health benefits provided by structured phospholipid using in vitro and in vivo models to access specific metabolic pathways.
In this study, a simultaneous analytical method of tocols, γ-oryzanols, phytosterols, squalene, cholecalciferol and phylloquinone were developed using HPLC-DAD-FLD. The developed method allowed the quantification of 18 compounds in 30 min. Method validation showed linearity of calibration curves (α = 0.05). RSD of intra-day, inter-day and inter-laboratory precision were less than 4.88%. The limit of detections (LODs) and limit of quantifications (LOQs) were low (0.009-2.166 μg g-1) with recoveries around 96.0-102.9%. Results derived from the established method demonstrated a wide variation of detected compounds in rice bran and vegetable oil samples (22.4-1774.6 μg g-1 tocols, ND-26484 μg g-1 γ-oryzanols, ND-12655 μg g-1 phytosterols, ND-3189 μg g-1 squalene, ND-105.3 μg g-1 cholecalciferol, and ND-54.4 μg g-1 phylloquinone). Thus, the developed HPLC-DAD-FLD method is a powerful analytical tool for the above mentioned compounds useful in food and pharmaceutical application.
Agro-industry yields ample quantity of several byproducts with considerable importance. These byproducts are mostly under-utilized, often used as animal feed or rejected as waste, hence their true potential is not harnessed. The use of such superfluous resources is not only of economic significance but also a form of commercial recycling. Rice bran is an important byproduct of rice milling industry with a global potential of 29.3 million tons annually. It is gaining great attention of the researchers due to its nutrient rich composition, easy availability, low cost, high antioxidant potential and promising effects against several metabolic ailments. Bioactive components of rice bran, mainly γ-oryzanol, have been reported to possess antioxidant, anti-inflammatory, hypocholesterolemic, anti-diabetic and anti-cancer activities. Rice bran oil contain appreciable quantities of bioactive components and has attained the status of "Heart oil" due to its cardiac friendly chemical profile. Nutraceutics have successfully been extracted from rice bran using several extraction techniques such as solvent extraction, supercritical fluid extraction, microwave assisted and ultrasonic assisted extraction. Current paper is an attempt to highlight bioactive moieties of rice bran along with their extraction technologies and health benefits.
Tocopherols and phytosterols were added to medium chain triacylglycerol (MCT) to study their effect on color reversion of vegetable oils. Four samples with 0, 6,000, 10,000 and 14,000 mg/kg phytosterols were heated at 105°c for 12 h. No significant reduction of phytosterols and obvious color change were found in the four samples. Five samples with 0, 1,000, 2,000, 5,000, 10,000 mg/kg tocopherols were also heated at 105°c for 12 h. About 2 . 5% tocopherols were absent after heating. Reduction of total tocopherol was found linearly related to color darkening. The most significant reduction is α-tocopherol. Reduction of α-tocopherol correlated more with color darkening than that of γ-tocopherol. The conclusion is phytosterol has no effect on color reversion of oils and reduction of α-tocopherol was attributed to be the most important cause of color reversion.
Rice bran oil was subjected to static heating at 180 + 2°C in a domestic fryer for 8 h in this process 150 ml of the heated
oil samples were drawn, at intervals of every 2 h, to study the changes in the physico-chemical characteristics. Results indicated
that the peroxide value and free fatty acid content increased gradually from 0.2 to 2.9 Meq.O2/kg of oil and 0.25 to 0.63%
respectively. The oil became darker as given by the colour value (5R + Y) 63 Lovibond units. Tocopherol content was found
to decrease from 48 mg/100gram to 5 mg/100gram at the end of 8 h of heating whereas, oryzanol was fairly stable (1.59 to 1.40%).
The p-anisidine value and Total polar compound (TPC) increased from 5.04 to 18.30 and 1.0 to1.8% respectively, showing the formation
of secondary oxidation products. Rice bran oil is a non-Newtonian fluids having shear thinning behavior. Heating was found
to cause an increase in the flow behavior index. Fatty acid composition did not show significant changes except for the linoleic
acid content which decreased from 29.4 to 27.1%.
Lipases are important biocatalysts showing many interesting properties with industrial applications. Previously, different isoforms of lipases, Lipase-I and Lipase-II from rice (Oryza sativa) have been purified and characterized. Lipase-II identified as the major lipase in rice bran is designated as rice bran lipase (RBL). In this study, we report the cloning and expression of the RBL in E. coli and Pichia pastoris. An exploration of expression in four different E. coli expression systems analysed: BL21(DE3)pLysS, RIL(DE3)pLysS, Rosetta(DE3)pLysS and Origami(DE3)pLysS indicated that E. coli was not a suitable host. Expression with supplement of rare codons in Rosetta (DE3)pLysS and RIL(DE3)pLysS resulted in highest expression as insoluble inclusion bodies. The hurdles of expression in E. coli were overcome by expression as a secretory protein in Pichia pastoris X-33. The expression of lipase in shake flasks was optimized to achieve the maximum recombinant lipase activity of 152.6 U/mL. The purified recombinant lipase had a specific activity of 998 U/mg toward triacetin. The pH and temperature optimum of native and recombinant enzymes were pH 7.4 and 25 ± 2 °C respectively. Both the lipases showed higher activity toward short chain triacylglycerol and unsaturated fatty acid enriched oils. Computational modelling and molecular docking studies reveal that the catalytic efficiency of the lipase correlates with the distance of the nucleophilic Ser(175)-OH and the scissile ester bond. The shorter the distance, the greater is the turnover of the substrate.