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![Phenolic acids and aldehydes reported in almond skins. Bars represent ranges and means. Bars at origin signify quantitative data not present in literature. Data derived from references in Table 1. + indicates detected in whole almond or almond skin. For B, * indicates compound detected in blanch water. Compounds quantitated in blanch water [mg/100 mL] included 5-hydroxybenzoic acid [0.2], protocatechuic acid [0.04], vanillic acid [0.02], 3-O-caffeoylquinic acid (chlorogenic acid) [0.04], trans-p-coumaric acid [0.004].](profile/Bradley-Bolling/publication/315469977/figure/fig5/AS:479078177349634@1491232546956/Phenolic-acids-and-aldehydes-reported-in-almond-skins-Bars-represent-ranges-and-means.png)
Phenolic acids and aldehydes reported in almond skins. Bars represent ranges and means. Bars at origin signify quantitative data not present in literature. Data derived from references in Table 1. + indicates detected in whole almond or almond skin. For B, * indicates compound detected in blanch water. Compounds quantitated in blanch water [mg/100 mL] included 5-hydroxybenzoic acid [0.2], protocatechuic acid [0.04], vanillic acid [0.02], 3-O-caffeoylquinic acid (chlorogenic acid) [0.04], trans-p-coumaric acid [0.004].
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Almond is a nutrient-dense tree nut recognized for its favorable lipid profile, vitamin E content, and polyphenols. The objectives of this review were to determine the polyphenols reported in almond, summarize the methods of analysis, and determine the polyphenol contribution to almond quality and health-promoting activity. Approximately 130 differ...
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... phenolic acids and aldehydes have been identified by HPLC-MS, capillary electrophoresis (CE)-MS, and GC-MS anal- ysis. Almond skin phenolic acids and aldehydes have been better characterized than from whole almond (Figure 6 and 7). The hydroxybenzoic acids p-hydroxybenzoic acid, 5-hydroxybenzoic acid, vanillic acid, and protocatechuic acid have been identified and quantitated in almond skin, with a mean of 8.31 mg/100 g. ...
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... All of the Phyllanthus urinaria tannins are hydrolyzable tannins [1]. Hydrolysable tannins include gallotannins, ellagitannins, and phlorotannins, which release gallic acid, ellagic acid, and phloroglucinol upon hydrolysis (Figure 7) [21]. Furthermore, methyl brevifolincarboxylate and ethyl gallate (Table 3) decreased in APU. ...
Phyllanthus urinaria is an annual perennial herbal species found in tropical Asia, America, China, and the Indian Ocean islands. Phyllanthus urinaria is used in folk medicine as a cure to treat jaundice, diabetes, malaria, and liver diseases. Sterilizing the substrate is a crucial step in the fermentation process. This process ensures that the inoculated microorganism is entirely single. Autoclave sterilization is widely favored within the scientific community. In autoclaving, pressurized steam is employed to deliver heat, effectively reducing the bioactive compounds present in the substrate. Comparative studies on various sterilization methods have been reported. This study aims to investigate the effects of substrate containers in sterilization methods of the herbal plant on phenol and flavonoid compounds by LC-MS (Liquid Chromatography-Mass Spectrometry) analysis. Three sterilization methods (pasteurization, steam, and autoclave sterilization) were each applied to the meniran herbal plant (Phyllanthus urinaria) for 15 minutes. Using the aluminum chloride colorimetric assay, the sterilization results were measured for total phenol content, the Folin-Ciocalteu test, and total flavonoid content. The LC-MS analysis showed that the methanol extract of Phyllanthus urinaria (APU) sterilized by autoclaving resulted in the most significant reduction in active phenolic and flavonoid compounds. Pasteurization, steaming, and autoclaving in a big container resulted in total flavonoid content of 1.80±0.034, 1.70±0.021, and 1.71±0.029 mg QE/g extract. The total phenolic content was 26.49±0.591, 22.77±0.230, and 22.097±0.155 mg GAE extract/g, respectively. Meanwhile, using a small container, each method produced a total flavonoid content of 1.73±0.024, 1.71±0.051, and 1.62±0.015 mg QE/g extract, respectively. The total phenolic content was 20.56±0.093, 19.79±0.295, and 20.09±0.124 mg GAE/g extract. Furthermore, the LC-MS profile revealed that APU experienced a reduction in ρ-hydroxybenzaldehyde and naringenin compounds, leading to a decrease in rutin, methyl brevifolincarboxylate, and ethyl gallate compounds. From the results of LC-MS analysis, this research determined that pasteurization using a big container is the most effective sterilization method for preserving the highest levels of total flavonoid and phenolic content in Phyllanthus urinaria while minimizing adverse effects on phytochemical compounds.
... The composition of AS with high phenolic content and different functional properties represents a high added value for this industrial by-product. Several authors [1,4,5] have reviewed the phenolic composition of AS reported in different studies using different extraction methods. The major components of AS are proanthocyanidins (dimers or larger molecules) (mean content: 6.98 mg.100 g −1 ), hydrolysable tannins, flavonoids (non-isoflavone) (71.3 mg.100 g −1 ), and phenolic acids and aldehydes (11.6 mg.100 g −1 ) [5]. ...
... Several authors [1,4,5] have reviewed the phenolic composition of AS reported in different studies using different extraction methods. The major components of AS are proanthocyanidins (dimers or larger molecules) (mean content: 6.98 mg.100 g −1 ), hydrolysable tannins, flavonoids (non-isoflavone) (71.3 mg.100 g −1 ), and phenolic acids and aldehydes (11.6 mg.100 g −1 ) [5]. In the complex phenolic profile of AS, different flavonol glycosides have been identified, namely, isorhamnetin rutinoside, isorhamnetin glucoside, kaempferol rutinoside, kaempferol glucoside, quercetin glycosylated to glucose, galactose and rhamnose, kaempferol, naringenin, catechin, protocatechuic acid, vanillic acid, and a benzoic acid derivative [4]. ...
Almond skin (AS) is an agro-industrial residue from almond processing that has a high potential for valorisation. In this study, subcritical water extraction (SWE) was applied at two temperatures (160 and 180 °C) to obtain phenolic-rich extracts (water-soluble fraction) and cellulose fibres (insoluble fraction) from AS. The extraction conditions affected the composition and properties of both valorised fractions. The dry extracts obtained at 180 °C were richer in phenolics (161 vs. 101 mg GAE. g−1 defatted almond skin (DAS)), with greater antioxidant potential (1.063 vs. 1.490 mg DAS.mg−1 DPPH) and showed greater antibacterial effect (lower MIC values) against L. innocua (34 vs. 90 mg·mL−1) and E. coli (48 vs. 90 mg·mL−1) than those obtained at 160 °C, despite the lower total solid yield (21 vs. 29%) obtained in the SWE process. The purification of cellulose from the SWE residues, using hydrogen peroxide (H2O2), revealed that AS is not a good source of cellulose material since the bleached fractions showed low yields (20–21%) and low cellulose purity (40–50%), even after four bleaching cycles (1 h) at pH 12 and 8% H2O2. Nevertheless, the application of a green, scalable, and toxic solvent-free SWE process was highly useful for obtaining AS bioactive extracts for different food, cosmetic, or pharmaceutical applications.
... They contain monounsaturated fat, fiber, and polyphenols such as tannins and flavonoids. These polyphenols are bioavailable and can be transformed by the body and its microbiota [105,106]. They have been shown to reduce inflammation and oxidative stress. ...
Obesity is a long-term condition resulting from a continuous imbalance between the amount of energy consumed and expended. It is associated with premature mortality and contributes to a large portion of the global chronic disease burden, including diabesity, cardiovascular disease, hypertension, and some cancers. While lifestyle changes and dietary adjustments are the primary ways to manage obesity, they may not always be sufficient for long-term weight loss. In these cases, medication may be necessary. However, the options for drugs are limited due to their potential side effects. As a result, there is a need to identify safe and effective alternative treatments. Recently, dietary compounds, plants, and bioactive phytochemicals have been considered as promising sources for discovering new pharmacological agents to treat obesity and its related complications. These natural products can function independently or synergistically with other plants to augment their effects at various levels of the body. They can modulate appetite, lipase activity, thermogenesis and fat synthesis and degradation, satiation, adipogenesis, and adipocyte apoptosis. Additionally, targeting adipocyte growth and differentiation with diverse medicinal plants/diet is a significant strategy for devising new anti-obesity drugs that can intervene in preadipocytes, maturing preadipocytes, and mature adipocytes. Clinical trials have shown that the wild edible plants in the Mediterranean diet can reduce the risk of obesity and its related diseases. This review examines the effectiveness of the common components of the Mediterranean diet in managing obesity and its associated health issues. We conducted a comprehensive literature review using PubMed, Science Direct, Google Scholar, and Medline Plus to gather data on the therapeutic effects of the Mediterranean diet and phytochemicals in treating obesity and its associated diseases.
... Polyphenols are secondary metabolites found in vegetables (such as kale, broccoli, and carrots) [15,16], grains and seeds (such as oats, almonds, barley, and wheat) [17][18][19], 2 of 17 fruits (such as berries, apple, and grapes) [20], and beverages (such as green tea, red wine, and coffee) [21][22][23]. They exhibit potential health benefits such as protection against ultraviolet radiation [24], antiviral [25], wound healing [26,27], anti-inflammatory, antimicrobial, antioxidant [27], and anti-melanogenic [28] properties. ...
Melanin production is an important process that prevents the host skin from harmful ultraviolet radiation; however, an overproduction of melanin results in skin diseases. In the present study, we determined the antioxidative and anti-melanogenic activities of polyphenol-and flavonoid-enriched rice seed extracts in melan-a cells. The polyphenol and flavonoid content of Hopum (HP) and Sebok (SB) rice seed extracts was measured. The antioxidant capacity was determined using the ABTS radical scavenging method. SB contained high amounts of polyphenols and flavonoids, which significantly increased antioxidative activity compared with HP. Various concentrations of these extracts were evaluated in a cytotoxicity using melan-a cells. At 100 µg/mL, there was no significant difference for all treatments compared with untreated cells. Therefore, 100 µg/mL was selected as a concentration for the further experiments. SB significantly suppressed the phosphorylation/activation of p-38 MAPK, increased the expression of phosphorylated ERK 1/2 and Akt, and downregulated the microphthalmia-associated transcription factor (MITF). This resulted in decreased levels of tyrosinase and tyrosinase-related protein-1 and-2. These results indicate the potential of polyphenol-and flavonoid-enriched rice seed as a treatment for hyperpigmentation.
... This work appears to be the first to successfully identify and quantify six phenolic compounds from the almond shells, corresponding to taxifolin (peaks 1 and 4), isoflavone daidzein (peak 6) and the derivates of quercetin (peak 17), ellagic acid (peak 14) and genistein (peak 7). All these compounds have been previously identified in other parts of the almond tree, such as stems, leaves or kernels [27][28][29]. ...
With great cultural significance, spirits and distillate beverages constitute an important niche market in Europe. The development of new food products, particularly for the functionalization of these beverages, is increasing exponentially. The present work aimed to develop a new wine spirit beverage aged with almond shells and flowers of P. tridentatum for further characterization of bioactive and phenolic compounds, coupled with a sensorial study to evaluate the acceptance of this new product by the market. Twenty-one phenolic compounds were identified, mainly isoflavonoids and O- and C-glycosylated flavonoids, especially in P. tridentatum flowers, indicating that it is a highly aromatizing agent. The developed liqueur and wine spirits (almonds and flowers) showed distinct physicochemical properties, with the last two samples showing greater appreciation and purchase intention by consumers due to their sweetness and smoothness. The most promising results were found for the carqueja flower, which should be further investigated in an industrial context to contribute to its valorization in its regions of origin, such as Beira Interior and Trás-os-Montes (Portugal).
... Almond or Prunus dulcis (Mill.) D.A Webb is one of the most popular tree nuts produced and consumed worldwide due to its favourable fatty acids profile, vitamin E content, and polyphenols [13]. Futhermore, almonds' high fibre and polyphenols content could be a substrate for microbial fermentation in the gut [14]. ...
Fermented foods are an important diet component of people around the world. Kefir, or fermented milk, is popular worldwide due to its high nutritional value, with cow's milk being the common substrate for traditional kefir fermentation. However, the scarcity of animal-based milk in some countries, plus cultural, religious, and health reasons, have seen non-dairy milk kefir from almond milk gaining popularity among consumers globally. This study aimed to evaluate and compare the proximate composition and anti-microbial activity of kefir produced from 100% cow or 100% almond or an equal (1:1) mixture of both kinds of milk. This study used the AOAC 2000 method for the proximate analysis, while the agar well diffusion method examined the anti-microbial activity of the milk samples against Escherichia coli, Staphylococcus aureus, and Salmonella typhi. Results revealed that the three kefir samples showed significantly different (p<0.05) moisture, total dietary fiber, and fat contents and were within the CODEX acceptable range for kefir. All samples exhibited varying degrees of inhibition between the different pathogens. The diameters of the inhibition zone of the tested kefir samples were significantly different toward Salmonella typhi (p<0.05), with the mixture of almond and cow milk notably producing better inhibition towards all tested bacteria. The above-said milk mixture also gave a better overall nutrient profile (lower fat and higher fibre). While almond milk might be a suitable substrate for kefir, it was not effectively inhibitory for all bacteria. The overall results thus conveyed the promising use of almond and cow milk mixture as an alternative substrate for kefir fermentation, further supporting its potential use as a probiotics source.
... They are considered a healthy and functional food [4,5] since they represent a reliable source of nutrients, including proteins, monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), vitamins, minerals, dietary fibres, and bioactive molecules with well-known antioxidant properties, such as polyphenols [1,[6][7][8]. Numerous epidemiological and clinical studies have shown that regular consumption of almonds, as part of a balanced diet, is associated with beneficial and protective health effects closely related to nutrient and non-nutrient compounds [1,4,5], such as reduction in blood levels of total cholesterol and low-density lipoprotein (LDL) [8], modulation of serum glucose levels, improvement in intestinal microbiota profile, and protection against obesity, diabetes, metabolic syndrome, and cardiovascular diseases [4,9,10]. ...
... The analyses carried out over the years on almond skins from different origins and harvests suggest that they can be considered an excellent source of polyphenols (≥10 mg/g) [10]. Despite several factors, including the extraction method, possibly affecting meaningful comparison, our results of total phenols content were comparable to those previously obtained by our group and other researchers [5,15,35,42]. ...
The almond industry produces, by bleaching and stripping, two by-products: blanched skin (BS) and blanch water (BW). The aim of this study was to investigate the nutritional and polyphenolic profile, as well as the antioxidant, antimicrobial, antiviral, and potential prebiotic effects of BS and BW from three different Sicilian cultivars. The total phenols and flavonoids contents were ≥1.72 and ≥0.56 g gallic acid equivalents and ≥0.52 and ≥0.18 g rutin equivalents/100 g dry extract (DE) in BS and BW, respectively. The antioxidant activity, evaluated by 2,2-diphenyl-1-picrylhydrazyl scavenging ability, trolox equivalent antioxidant capacity, ferric-reducing antioxidant power, and oxygen radical absorbance capacity, was ≥3.07 and ≥0.83 g trolox equivalent/100 g DE in BS and BW, respectively. Isorhamnetin-3-O-glucoside was the most abundant flavonoid detected in both by-products. No antimicrobial effect was recorded, whereas BS samples exerted antiviral activity against herpes simplex virus 1 (EC50 160.96 μg/mL). BS also showed high fibre (≥52.67%) and protein (≥10.99) contents and low fat (≤15.35%) and sugars (≤5.55%), making it nutritionally interesting. The present study proved that the cultivar is not a discriminating factor in determining the chemical and biological properties of BS and BW.
... Studies on the almond composition have shown that it has a high content of bioactive compounds such as fatty acids, lipids, amino acids, proteins, carbohydrates, dietary fibers, phytosterols, polyphenols, vitamins, and minerals, as well as other secondary metabolites [50,51]. In this sense, there is a large number of studies suggesting that the consumption of almonds reduces the risk of cardiovascular disease, improves diet and contributes to satiety, improves the inflammatory processes associated with metabolic syndrome and type 2 diabetes, has prebiotics and antioxidant functions, can contribute to the prevention of cancer and cellular stress, and can act as immuno-modulator [52][53][54][55]. The nutrient composition of almonds depends mainly on the genotype, although it can also be influenced by other factors, such as edaphoclimatic conditions, the growing region, cultivation practices, grain maturity, etc., or the interactions of these factors [51,56]. ...
The implementation of soil conservation measures is essential to promote sustainable crop production in the Mediterranean region. In an organic rainfed almond orchard located in Lanjarón (SE, Spain), a study carried out during 2016–2021 analyzed the influence of different soil management strategies (SMSs) (TT, traditional tillage; NT, no tillage; VF, cover of Vicia faba; VS, cover of Vicia sativa; VS-VE, cover of Vicia sativa and Vicia ervilia) on some selected physical (bulk
density, available water content, and aggregate stability), chemical (pH, electrical conductivity, soil-organic content, N, P, K, and micronutrients), and biological (microbial activity) soil properties, relevant to soil health, and their implications for yield and almond quality (physical and chemical). Our results showed that the SMS with legume cover improves soil properties, which had a favorable effect on soil health. The mean almond yield was not significantly affected by the SMS applied, being 315.9, 256.4, 229.1, 212.5, and 176.6 kg ha−1 year−1 for TT, VF, VS-VE, VS, and
NT, respectively. Regarding the almond nut quality, the strategy based on implementation of legume cover increased the almond antioxidant activity and the total polyphenol content, which would improve their nutritional value. Here we showed how the use of sustainable SMSs improved the soil properties compared to traditional tillage in rainfed organic almonds, allowing the long-term sustainability of agroecosystems while at the same time obtaining higher nutritional quality almonds.
... It is ascertained that almond skins are rich of bioactive phytochemicals such as flavonoids, phenolic acids and proanthocyanidins, accounting for about 70-80 % of the polyphenols in the whole almond fruit (Bolling, 2017;Mandalari et al., 2010;Shahidi et al., 2019). The total phenols content in the PAS used in our study was extracted with acidified ethanol solution and measured by Folin-Ciocalteu method with a result of 8.72 ± 0.22 mg GAE/g (n = 4). ...
Almond production generates large amounts of by-products rich in polyphenols. In this study, almond skin was explored as a valuable food ingredient in bread making. To this purpose, almond skin was used to produce functional products modifying a traditional sourdough bread recipe. The doughs were prepared replacing semolina with powdered almond skin (PAS) at 5 and 10 % (w/w). Sourdough inoculum was started with a mix of lactic acid bacteria (LAB) and propagated in semolina until reaching pH 3.7. The pH of PAS added breads was higher than that of control (CTR) breads before and after fermentation. Plate counts showed a similar evolution of LAB and total mesophilic microorganisms, but members of Enterobacteriaceae and coliform were detectable in PAS doughs. Illumina data clearly showed a dominance of lactobacilli in all trials, but PAS doughs displayed the presence of Bacillus. The final bread characteristics were influenced by PAS and its addition percentage; in particular, crust and crumb colour resulted darker, the alveolation decreased and, regarding sensory attributes, odour intensity increased, while bread odour diminished. In presence of PAS, bread emissions were characterized by lower percentages of alcohols and aromatic hydrocarbons and higher percentages of the other volatile compound classes, especially terpenoids like β-pinene, β-myrcene and limonene than CTR trial. After in vitro simulated digestion, the final release of phytochemicals from 10 % PAS bread was almost 100 %. Thus, PAS determined an increase of the antioxidant capacity of the breads. Phytochemicals released from digested PAS-fortified bread can provide antioxidant protection in a complex biological environment such as human intestinal-like cells. Besides the positive functional properties of PAS, this work also evidenced the hygienic issues of almond skin and, in order to avoid potential risks for the human health, highlighted the need to preserve its microbiological characteristics during storage for their reuse in bread production.
... teristics of products, the latter, for example, through the partial denaturation of almond proteins and the change of the profile of fatty acids, and might be harmful to valuable micronutrients, such as polyphenols of both almond skin and skinless kernel [24][25][26]. ...
... The analyses were performed in triplicate. However, it was anticipated that the recovery and quantification of polyphenols from raw almond materials during laboratory analysis is critically dependent on the details of the method and could be affected by greater systematic uncertainties than declared [24], an issue that does not affect the analysis of clear aqueous extracts. As further pointed out in Section 4, such concern was confirmed by the results obtained in this study, involving also vitamins; thus, the measurements of the content of polyphenols and vitamins performed on raw almond materials were discarded from the analysis. ...
... The bimodal structure of the extraction rate, with two peaks at the beginning of the processes up to 40 • C, and in the later phase (68 • C to 86 • C), is likely to reflect the complex composition of polyphenols of almond kernels, a few tenths of which were identified and characterized [9]. The extraction rate of those polyphenols from almond kernels, and thus their identification and quantification, was found to be remarkably dependent on the extraction method, such as the used solvent, temperature, etc. [9,24], hence the complex pattern of the extraction rate emerging from tests MFP1 and MGP1. ...
Perceived as a healthy food, almond beverages are gaining ever-increasing consumer preference across nonalcoholic vegetable beverages, ranking in first place among oilseed-based drinks. However, costly raw material; time and energy consuming pre-and posttreatments such as soaking, blanching and peeling; and thermal sterilization hinder their sustainability, affordability and spread. Hydrodynamic cavitation processes were applied, for the first time, as a single-unit operation with straightforward scalability, to the extraction in water of almond skinless kernels in the form of flour and fine grains, and of whole almond seeds in the form of coarse grains, up to high concentrations. The nutritional profile of the extracts matched that of a high-end commercial product, as well as showing nearly complete extraction of the raw materials. The availability of bioactive micronutrients and the microbiological stability exceeded the commercial product. The concentrated extract of whole almond seeds showed comparatively higher antiradical activity, likely due to the properties of the almond kernel skin. Hydrodynamic cavitation-based processing might represent a convenient route to the production of conventional as well as integral and potentially healthier almond beverages, avoiding multiple technological steps, while affording fast production cycles and consuming less than 50 Wh of electricity per liter before bottling.
