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Mushrooms contain phenolic compounds that possess health-promoting properties, including antioxidant effects. However, the low solubility and form of phenolic compounds affect their bioactivity and bioaccessibility. To overcome this limitation, our study investigates the fermentation of mushrooms to increase their free phenolic content and enhance their bioactivity. Our research focused on the impact of fermentation on both free and bound phenolic fractions (FPs and BPs, respectively) in Lentinula edodes and Lactarius deliciosus, which were successively fermented with Lactiplantibacillus plantarum LMG 17673 for 72 h. We examined the total phenolic content (TPC), phenolic profile, and antioxidant activity of both FPs and BPs. Our results showed that the TPC of BPs was higher than that of FPs in both mushrooms, with strong antioxidant capabilities. Fermentation significantly increased the TPC of FPs in both mushrooms, particularly after 24 h of fermentation. The TPC of BPs in mushrooms decreased during fermentation, indicating their release from the matrix. Additionally, we identified 30 bioactive compounds using UPLC-Q-TOF-MS/MS. Our study demonstrates for the first time that lactic acid bacteria fermentation of mushrooms with high phenolic content leads to the liberation of bound phenolics, enhancing their bioactivity and bioaccessibility. [ABSTRACT FROM AUTHOR]

ABSTRACTThe aim of this study was to investigate acid hydrolysis-bound phenols from Rosa roxburghii Tratt and their biological activities in vitro. The optimal extraction parameters were as follows: HCl concentration of 7 mol/L, extraction time of 10 h and material-liquid ratio of 1:40 g/mL. The highest yield of bound polyphenols was 495.64 ± 11.66 mg GAE/100 g DW. There were 24 phenolic compounds and 14 flavonoids released by acid hydrolysis. The antioxidant study showed that the RRT-BPs had a certain scavenging ability of free radicals in a dose-dependent manner. RRT-BPs showed good inhibitory activity against α-glucosidase and pancreatic lipase, respectively, and RRT-PBs acted as anticompetitive and mixed inhibitors against α-glucosidase and pancreatic lipase, respectively. Our study suggests that acid-hydrolysed bound phenols have good prebiotic properties and can be used as a supplement to existing alkaline-hydrolysed bound phenols to prevent chronic diseases such as diabetes and obesity.

To investigate the effects of particle size and phenolics bounded-insoluble dietary fiber (IB) of white kidney bean skin (WS) on in vitro fermentation profiles, the IB was extracted enzymatically, modified by ordinary and superfine grinding, followed by the preparation of different particle sizes. Their microscopic morphology was observed by scanning electron microscopy and laser confocal scanning microscopy. In vitro fermentation experiments and 16S rRNA sequencing were used to investigate the fermentation properties of the two sets of samples and their effects on the abundance of gut microbiota composition. The results showed that the bound phenolics were distributed more equally on the surface of the smaller particles. The slowed fermentation rate and short-chain fatty acid production of WS and IB increased with decreasing particle size. The smaller particle size promoted the Bacteroides and demoted the Lachnospira more significantly. The results suggested that IB could promote the beneficial bacteria such as Bacteroides, Bifidobacterium and Ruminococcaceae ruminococcus, and regulate the structure composition of the gut microbiota. The probiotic effect of IB was more significant than that of WS with the same particle size. This study provides the school of thought on the prebiotic effect of dietary fiber, guides on the modification of dietary fiber by superfine grinding, and suggests the comprehensive utilization of white kidney bean skin.

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Olive leaves are rich in phenolic compounds. This study explored the chemical profiles and contents of free phenolics (FPs) and bound phenolics (BPs) in olive leaves, and further investigated and compared the antioxidant properties of FPs and BPs using chemical assays, cellular antioxidant evaluation systems, and in vivo mouse models. The results showed that FPs and BPs have different phenolic profiles; 24 free and 14 bound phenolics were identified in FPs and BPs, respectively. Higher levels of phenolic acid (i.e., sinapinic acid, 4-coumaric acid, ferulic acid, and caffeic acid) and hydroxytyrosol were detected in the BPs, while flavonoids, triterpenoid acids, and iridoids were more concentrated in the free form. FPs showed a significantly higher total flavonoid content (TFC), total phenolic content (TPC), and chemical antioxidant properties than those of BPs (p < 0.05). Within the range of doses (20–250 μg/mL), both FPs and BPs protected HepG2 cells from H2O2-induced oxidative stress injury, and there was no significant difference in cellular antioxidant activity between FPs and BPs. The in vivo experiments suggested that FP and BP treatment inhibited malondialdehyde (MDA) levels in a D-galactose-induced oxidation model in mice, and significantly increased antioxidant enzyme activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and the total antioxidant capacity (T-AOC). Mechanistically, FPs and BPs exert their antioxidant activity in distinct ways; FPs ameliorated D-galactose-induced oxidative stress injury partly via the activation of nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway, while the BP mechanisms need further study. [ABSTRACT FROM AUTHOR]

Mushrooms contain phenolic compounds that possess health-promoting properties, including antioxidant effects. However, the low solubility and form of phenolic compounds affect their bioactivity and bioaccessibility. To overcome this limitation, our study investigates the fermentation of mushrooms to increase their free phenolic content and enhance their bioactivity. Our research focused on the impact of fermentation on both free and bound phenolic fractions (FPs and BPs, respectively) in Lentinula edodes and Lactarius deliciosus, which were successively fermented with Lactiplantibacillus plantarum LMG 17673 for 72 h. We examined the total phenolic content (TPC), phenolic profile, and antioxidant activity of both FPs and BPs. Our results showed that the TPC of BPs was higher than that of FPs in both mushrooms, with strong antioxidant capabilities. Fermentation significantly increased the TPC of FPs in both mushrooms, particularly after 24 h of fermentation. The TPC of BPs in mushrooms decreased during fermentation, indicating their release from the matrix. Additionally, we identified 30 bioactive compounds using UPLC-Q-TOF-MS/MS. Our study demonstrates for the first time that lactic acid bacteria fermentation of mushrooms with high phenolic content leads to the liberation of bound phenolics, enhancing their bioactivity and bioaccessibility.

Valorisation of food and agricultural waste can provide a cost-effective substrate source for laccase catalysis. This study evaluated the suitability of potato peels as feedstock for laccase-catalysed modification into value-added products. The optimal conditions for extracting the highest yield of chlorogenic acid (CLA) from potato peels were 300 W (ultrasonication power) and 39.375 min (extraction time). Alkaline hydrolysis of CLA extracted from potato peels produced caffeic acid (CFA) (yield 76.1%) which was in turn oxidised by laccase to produce phellinsin A (yield 32.8%, ~ 1/3 of CLA). Transformation from CLA to phellinsin A resulted in ~ two-fold increase in antioxidant capacity. Phellinsin A exhibited 16.7 and 8.6% cytotoxicity activity against MCF-7 (breast cancer) and HEK-293 (human embryonic kidney) cell lines, respectively. The low cytotoxicity of phellinsin A against normal human cells, coupled with its enhanced antioxidant properties, indicates a good antioxidant ingredient. Based on global potato production statistics, this hydrolytic process can annually recover 1.08e4 tons of CFA from potato peels, subsequently producing 3.53e3 tons of phellinsin A by laccase catalysis. Therefore, potato peel waste is a viable substrate source for laccase-catalysed synthesis of value-added bioactive compounds. [ABSTRACT FROM AUTHOR]

Rice bean (Vigna umbellata) is a medicinal and dietary legume rich in polyphenols. In this study, the free and bound phenolics in rice bean were extracted by water, 80% methanol, and acid, base, and composite enzymatic hydrolysis, respectively. The polyphenol profiles of the extracted fractions were analyzed. The outcome demonstrated that base hydrolysis was the most effective way to liberate bound phenolics from rice bean (14.18 mg GAE/g DW), which was 16.68 and 56.72 folds higher than those extracted by acid and enzymatic hydrolysis, respectively. The bound polyphenols released by base hydrolysis contributed to 71.15% of the total phenolic content. A total of 35 individual phenolics was identified, of which isoquercitrin, procyanidin B1, rutin, taxifolin, and catechin were the main monomeric phenolics in the free fraction, while gallic acid, protocatechuic acid, p-hydroxybenzoic acid, catechin, and phloroglucinol were the main monomeric phenolics in the bound fraction. In comparison to the free phenolics extracted by water and 80% methanol and the bound phenolics extracted using acid and composite enzymatic hydrolysis, the bound phenolics from base hydrolysis had a superior antioxidant capacity. The antioxidant activity of rice bean is primarily attributed to individual phenolics such as catechin, abundant both in free and bound fractions, and also p-hydroxybenzoic acid, gallic acid, and protocatechuic acid in bound fractions. The bound phenolics of rice bean were first reported and showed large differences with the composition of free phenolics. This work suggests that the bound fraction of rice bean must be taken into account in assessing its potential benefits to health. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Usually found bound to other complex molecules (e.g., lignin, hemicellulose), phenolic compounds (PC) are widely present in agro-industrial by-products, and their extraction is challenging. In recent times, research is starting to highlight the bioactive roles played by bound phenolics (BPC) in human health. This review aims at providing a critical update on recent advances in green techniques for the recovery of BPC, focusing on enzymatic-assisted (EAE) and fermentation-assisted extraction (FAE) as well as in the combination of technologies, showing variable yield and features. The present review also summarizes the most recent biological activities attributed to BPC extracts until now. The higher antioxidant activity of BPC—compared to FPC—coupled with their affordable by-product source make them medicinally potent and economically viable, promoting their integral upcycling and generating new revenue streams, business, and employment opportunities. In addition, EAE and FAE can have a biotransformative effect on the PC itself or its moiety, leading to improved extraction outcomes. Moreover, recent research on BPC extracts has reported promising anti-cancer and anti-diabetic activity. Yet further research is needed to elucidate their biological mechanisms and exploit the true potential of their applications in terms of new food products or ingredient development for human consumption. [ABSTRACT FROM AUTHOR]

The free and bound phenolic constituents in Dendrocalamus hamiltonii shoots were evaluated and compared to processed bamboo candy. Preliminary proximate analysis revealed a percent reduction in moisture and protein with a less significant change in fibre content. The fresh free phenolic extract (FFPE) exhibited a total phenolics of 131.22 mg GAE/g and recovered 48.29 mg GAE/g phenolic content in bound fraction (FBPE). Results demonstrated higher loss of free phenolics after processing compared to bound fraction (CBPE). Although similar results were observed in total flavonoid content. Antioxidant activity was reduced after candy processing, with fresh shoots having the lowest percent inhibition (IC50) against DPPH· and ABTS· radicals. Although both free and bound fractions of candy demonstrated effective antioxidant activity. HPLC analysis revealed that FFPE contained more chlorogenic acid (0.14 mg/10 g) and cinnamic acid (0.75 mg/10 g) than CFPE. Quercetin was undetected in all free fractions but was found in bound form. [ABSTRACT FROM AUTHOR]

Olive leaves are rich in phenolic compounds. This study explored the chemical profiles and contents of free phenolics (FPs) and bound phenolics (BPs) in olive leaves, and further investigated and compared the antioxidant properties of FPs and BPs using chemical assays, cellular antioxidant evaluation systems, and in vivo mouse models. The results showed that FPs and BPs have different phenolic profiles; 24 free and 14 bound phenolics were identified in FPs and BPs, respectively. Higher levels of phenolic acid (i.e., sinapinic acid, 4-coumaric acid, ferulic acid, and caffeic acid) and hydroxytyrosol were detected in the BPs, while flavonoids, triterpenoid acids, and iridoids were more concentrated in the free form. FPs showed a significantly higher total flavonoid content (TFC), total phenolic content (TPC), and chemical antioxidant properties than those of BPs (p < 0.05). Within the range of doses (20–250 μg/mL), both FPs and BPs protected HepG2 cells from H2O2-induced oxidative stress injury, and there was no significant difference in cellular antioxidant activity between FPs and BPs. The in vivo experiments suggested that FP and BP treatment inhibited malondialdehyde (MDA) levels in a D-galactose-induced oxidation model in mice, and significantly increased antioxidant enzyme activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and the total antioxidant capacity (T-AOC). Mechanistically, FPs and BPs exert their antioxidant activity in distinct ways; FPs ameliorated D-galactose-induced oxidative stress injury partly via the activation of nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway, while the BP mechanisms need further study.

Summary: In this work, the release pattern of bound phenolics in salt‐dried bamboo shoots (SDBS), steamed dried bamboo shoots (TDBS), fumigation dried bamboo shoots (UDBS) and fermentation dried bamboo shoots (FDBS) during simulated in vitro digestion was studied. The result exhibited that polyphenols in dried bamboo shoots (DBS) mainly existed in the form of bound phenolics, amongst them the content of FDBS was the highest, followed by SDBS and TDBS, and UDBS was the lowest. In addition, release amounts of bound phenolics in SDBS, TDBS, UDBS and FDBS after gastrointestinal digestion were significantly higher than that after gastric digestion, accounting for 19.61%, 19.40%, 45.64% and 19.66% of the total, respectively. Moreover, IC50 values for scavenging ability of DPPH and ABTS radicals by gastric and gastrointestinal digestion supernatant for DBS were in a descending order: FDBS, UDBS, SDBS and TDBS. Rutin, p‐coumaric and ferulic acid were discovered to be the predominant compounds in digestion supernatant. Trustworthy, fluorescence microscope pictures of DBS at different digestion stages further confirmed the release regularity of bound phenolics. Therefore, these findings could provide a theoretical support for the optimal processing of DBS. [ABSTRACT FROM AUTHOR]

Folin-Ciocalteu method and sodium nitrite-aluminum chloride method were used to determine total phenolic content and flavonoid content of bound phenolics from the inflorescences, peduncles and leaves of Ottelia acuminata (O. acuminata), respectively. The composition of bound phenolics was analyzed by high performance liquid chromatography (HPLC). The antioxidant activity and protective effect against ROO· mediated DNA damage were also investigated. The results showed that total phenolic content of O. acuminata was in the range of 209.72~366.35 mg GAE/g Extract while total flavonoid content was in the range of 156.69~466.08 mg CAE/g Extract. Five phenolics, namely, caffeic acid, quercetin-3-O-glucoside, luteolin, chlorogenic acid and ferulic acid were identified in bound phenolics of O. acuminata. Trolox equivalent antioxidant activity (TEAC), 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) radical scavenging ability, iron ion reduction antioxidant ability (FRAP) and hydroxyl radical (·OH) scavenging rate IC50 value of different plant parts were in the range of 1.19~1.25 μmol TE/g Extract, 0.74~0.94 mmol/g Extract, 3.61~4.75 mmol Fe2+/g Extract, 0.34~1.26 mg/mL, respectively, among which the leaves displayed the strongest antioxidant activity. In the concentration range of 12.5~500 mg/mL, the percentage of double helix DNA in bound phenolics of inflorescences, peduncles and leaves ranged from 22.74% to 50.07%, 18.25% to 53.28% and 25.93% to 53.60%, respectively, among which the leaves showed the strongest DNA damage protective effect, followed by the peduncles. The results showed that O. acuminata was rich in bound phenolics which possessed strong antioxidant activity and DNA damage protective effect.

[Display omitted] • 14 bean landraces and 2 commercial varieties were included in the present study. • Main carotenoids identified and quantified were lutein and zeaxanthin. • γ-tocopherol and δ-tocopherol were the main tocochromanols. • Dietary fiber reduced the bioaccessibility of carotenoids. • (Poly)phenols reduced the bioaccessibility of iron. Common beans (Phaseolus vulgaris L.) are among the most important legumes for human nutrition. The aim of the present study was to characterize the composition and in vitro bioaccessibility of tocochromanols, carotenoids, and iron from 14 different landraces and 2 commercial common bean varieties. Phytic acid, dietary fiber, and total (poly)phenolic content were determined as factors that can modify the bioaccessibility of the studied compounds. Two carotenoids were identified, namely lutein (4.6–315 ng/g) and zeaxanthin (12.2–363 ng/g), while two tocochromanols were identified, namely γ-tocopherol (2.62–18.01 µg/g), and δ-tocopherol (0.143–1.44 µg/g). The iron content in the studied samples was in the range of 58.7–144.2 µg/g. The contents of carotenoids, tocochromanols, and iron differed significantly among the studied samples but were within the ranges reported for commercial beans. After simulated gastrointestinal digestion, the average bioaccessibility of carotenoids was 30 %, for tocochromanols 50 %, and 17 % for iron. High variability in the bioaccessible content yielded by the bean varieties was observed. Dietary fiber, phytic acid and total (poly)phenol contents were negatively correlated with the bioaccessibility of carotenoids, while iron bioaccessibility was negatively correlated with the total (poly)phenol content. The principal component analysis indicated that the bioaccessibility of lutein was the main variable involved in class separations. The composition of the food matrix plays an important role in the bioaccessibility of carotenoids, tocochromanols and iron from cooked beans. [ABSTRACT FROM AUTHOR]

Radix puerariae thomsonii (RPT) contains many phenolics and exhibits various health benefits. Although the free phenolics in RPT have been identified, the composition and content of bound phenolics, which account for approximately 20% of the total phenolic content, remain unknown. In this study, 12 compounds were isolated and identified from RPT-bound phenolic extracts, of which 2 were novel and 6 were reported first in RPT. ORAC and PSC antioxidant activities of 12 compounds, as well as their effects on alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), α-glucosidase, and α-amylase were evaluated. Genistein exhibited the highest ORAC activity, while daidzin demonstrated superior PSC activity. Five compounds, including two new compounds, exhibited the ability to activate both ADH and ALDH. All the compounds except 4-hydroxyphenylacetic acid methyl ester and 2,4,4′-trihydroxydeoxybenzoin demonstrated inhibitory effects on α-glucosidase and α-amylase. Alkaline hydrolysis and stepwise enzymatic hydrolysis revealed that bound phenolics in RPT mainly exist within starch. [Display omitted] • Two new bound phenolic compounds were isolated from Radix Puerariae Thomsonii (RPT). • RPT starch was the main binding site for its bound phenolics. • Bound phenolics of RPT could enhance the activity of alcohol-metabolizing enzymes. [ABSTRACT FROM AUTHOR]

Summary: Shiitake mushrooms contain free phenolics (FPs) and bound phenolics (BPs). BPs embedded in mushrooms are generally neglected and underestimated. Methods of hydrolysis with acid, base and their combination in different sequences were developed to release BPs. The contents, compositions and antioxidant capacities of FPs and BPs were investigated. Results found that BPs yielded with combining base and acid hydrolysis received the highest value (25.67 mg gallic acid equivalents (GAE)/100 g dry weight (DW)), which was higher than FPs (20.62 mg GAE/100 g DW). LC‐ESI‐QqQ‐MS/MS analysis demonstrated that gallic acid, protocatechuic acid, caffeic acid, and ferulic acid presented in all BPs fractions, whereas hesperidin, luteolin, quercetin, and cinnamic acid were affected by hydrolysis methods and procedures. BPs fractions with higher phenolic content showed strong antioxidant capacities. These results demonstrate the importance of BPs and can be applied to enhance the amount and bioavailability of BPs from shiitake mushrooms and other foods. [ABSTRACT FROM AUTHOR]

Summary: Phenolics in whole grains naturally occur in free and bound forms, and are dominated by the latter. Previous study indicated that bound phenolics played an indispensable role in the health benefits of whole grain dietary fibre. However, existing extraction methods can only partly release bound phenolics, which results in an underestimation of their contents and activity. The content, composition and antioxidant activity of bound phenolics released from rice bran dietary fibre (RBDF) by different chemical hydrolysis methods were analysed in this study to explore a method releasing much more bound phenolics. The results showed that alkaline hydrolysis could release 1.54 times more phenolics than acid hydrolysis. The combination of 2 hydrolysis methods, especially alkaline‐acid hydrolysis (the residue after alkaline hydrolysis was then hydrolysed with acid), could more effectively release bound phenolics from RBDF. The 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) antioxidant activity of the RBDF hydrolysates from different hydrolysis methods were generally consistent with their phenolic contents. However, the alkaline hydrolysate had 7.62% less phenolics, but showed 53.03% higher CAA activity than the acid‐alkaline hydrolysate. The RBDF residues after different chemical hydrolysis, furthermore, exhibited considerable DPPH and FRAP activity by QUENCHER method, indicating their possible local antioxidant activity in the colonic microenviroment. [ABSTRACT FROM AUTHOR]

Mulberry seeds are a byproduct of juice processing and may be an important resource for its abundant compounds. In this study, we analyzed the qualitative composition of free and bound phenolics from six varieties of mulberry seeds using UPLC-ESI-QTOF-MS/MS. Free phenolics (FPs) and bound phenolics (BPs) were measured using the Folin–Ciocalteu method; antioxidant capacity was determined by measuring 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, using the ferric reducing antioxidant power assay. A total of 28 free and 11 bound phenolics were extracted and identified, wherein five free phenolics were found in mulberry matrices for the first time. The six varieties of mulberry seeds exhibited higher content of FPs than BPs, and there was a correlation between the phenolic content and antioxidant capacity. Consequently, three varieties were selected for their high phenolic content and antioxidant capacity. This study might offer a theoretical basis for the utilization of mulberry seed. [ABSTRACT FROM AUTHOR]

Rice bean (Vigna umbellata) is a medicinal and dietary legume rich in polyphenols. In this study, the free and bound phenolics in rice bean were extracted by water, 80% methanol, and acid, base, and composite enzymatic hydrolysis, respectively. The polyphenol profiles of the extracted fractions were analyzed. The outcome demonstrated that base hydrolysis was the most effective way to liberate bound phenolics from rice bean (14.18 mg GAE/g DW), which was 16.68 and 56.72 folds higher than those extracted by acid and enzymatic hydrolysis, respectively. The bound polyphenols released by base hydrolysis contributed to 71.15% of the total phenolic content. A total of 35 individual phenolics was identified, of which isoquercitrin, procyanidin B1, rutin, taxifolin, and catechin were the main monomeric phenolics in the free fraction, while gallic acid, protocatechuic acid, p-hydroxybenzoic acid, catechin, and phloroglucinol were the main monomeric phenolics in the bound fraction. In comparison to the free phenolics extracted by water and 80% methanol and the bound phenolics extracted using acid and composite enzymatic hydrolysis, the bound phenolics from base hydrolysis had a superior antioxidant capacity. The antioxidant activity of rice bean is primarily attributed to individual phenolics such as catechin, abundant both in free and bound fractions, and also p-hydroxybenzoic acid, gallic acid, and protocatechuic acid in bound fractions. The bound phenolics of rice bean were first reported and showed large differences with the composition of free phenolics. This work suggests that the bound fraction of rice bean must be taken into account in assessing its potential benefits to health.

Diet rich in phenolics would potentially associate with multiple health benefits. Response surface methodology (RSM) was introduced to optimize the process of ultrasound- and microwave-assisted extraction of bound phenolics from the bran of a newly developed black wheat breeding line Jizi439 and then compared with the traditional alkaline method. The optimum conditions were found to be 66 °C, 48 min, and power 240 W for ultrasound-assisted extraction (UAE), and 120 s, power 420 W for microwave-assisted extraction (MAE), respectively. Total bound phenolic contents (TBPCs), determined by Folin-Ciocalteu reagent, were 8466.7 ± 240.9 μg gallic acid equivalents per gram (μg GAE/g) bran for UAE and 8340.7 ± 146.7 μg GAE/g bran for MAE under optimized conditions, which were both significantly higher than that of the traditional method (5688.9 ± 179.6 μg GAE/g) (p < 0.05). Antioxidant activities (AAs) were determined by DPPH and ABTS methods. UAE extracts showed the highest DPPH scavenging activity (77.5 ± 0.9%), while MAE extracts showed the highest ABTS scavenging activity (72.1 ± 0.6%). Both were significantly higher than that of the traditional method (69.6 ± 1.1% for DPPH and 65.9 ± 0.5% for ABTS) (p < 0.05). Total bound phenolics (TBPs) profiles were further analyzed by HPLC, and results indicated that ferulic acid was dominant, followed by vanillic acid and p-coumaric acid. The contents of each identified individual phenolics were significantly increased by ultrasound and microwave. In conclusion, UAE and MAE were comparable with each other in TBP yields and AAs; however, when taking operation time and energy consumption into consideration, MAE was more efficient than UAE. Our study suggested efficiency extraction methods for further use of bound phenolics as a healthy food ingredient. [ABSTRACT FROM AUTHOR]

Phenolics in bound form extensively exist in cereal dietary fiber, especially insoluble fiber, while their release profile in gastrointestinal tract and contribution to the potential positive effects of dietary fiber in modulating gut microbiota still needs to be disclosed. In this work, the composition of bound phenolics (BPs) in triticale insoluble dietary fiber (TIDF) was studied, and in vitro gastrointestinal digestion as well as colonic fermentation were performed to investigate BPs liberation and their role in regulating intestinal flora of TIDF. It turned out that most BPs were unaccessible in digestion but partly released continuously during fermentation. 16 s rRNA sequencing demonstrated that TIDF possessed prebiotic effects by promoting anti-inflammatory while inhibiting proinflammatory bacteria alongside boosting SCFAs production and antioxidative BPs contributed a lot to these effects. Results indicated that TIDF held capabilities to regulate intestinal flora and BPs were important functional components to the health benefits of cereal dietary fiber. • 19 bound phenolics (BPs) were found in triticale insoluble dietary fiber (TIDF). • The release profile of BPs in gastrointestinal tract was uncovered in vitro. • The liberated BPs showed noticeable radical scavenging abilities. • BPs in TIDF showed synergetic prebiotic effects with fiber component. [ABSTRACT FROM AUTHOR]

ABSTRACT: Background: Finger millet (FM, Eleusine coracana (L) Gaertn; also known as “ragi” in Kannada language) is one of the widely used millets especially in south India and parts of Africa. FM is consumed in various forms that include porridge, mudde (ball), dosa (a pan cake), idly (a savory rice cake) and biscuits/cookies. FM is also used in the form of malted drink known as “malted ragi or ragi malt”. FM is a rich source of dietary fiber, tannins, phenolic compounds and calcium. Prior studies have shown health beneficial properties such as anti-diabetic and anti-inflammatory effects of FM, and ascribed those properties to the presence of dietary fiber and phenolic compounds. But, very minimal information is available pertaining to the effect of FM phenolic compounds on cell lines representing carcinomas of colon and rectum; and breast. Hence, we have studied the effect of FM phenolic compounds on colorectal carcinoma and breast cancer cell lines. Methods: Sequentially extracting the seeds by 70% ethanol and 10% alkali generated free (FM-FP) and bound (FM-BP) phenolic compounds respectively. UPLC-QTOF-MS was used to determine the phytochemical composition. Antioxidant potential was determined by ferric reducing antioxidant power assay (FRAP) and radical scavenging activity (DPPH assay). Effect of FM-FP and FM-BP on cellular proliferation was determined by sulforhodamine-B assay. Staining the untreated and treated cells with acridine orange and ethidium bromide followed by analyzing the stained cells using fluorescence microscope yielded key information about impact of extracts on cell death. Effect on cell cycle was determined by staining the cells with DAPI followed by analyzing the stained cells using NC-3000. Results: Analysis of the UPLC-QTOF -MS data showed the presence of phenolics and phenolic acid derivatives, flavonoids and aminoacids in the FM-FP and FM-BP fractions. Both fractions exhibited ferric ion reduction ability and DPPH radical scavenging potential. But, the effect of FM-FP and FM-BP on cell proliferation varied significantly from cell line to cell line. FM-FP exhibited better cytotoxic potential compared to FM-BP when tested against breast cancer cell lines. Cytotoxic FM-FP induced G0/G1 or G2/M arrest in a cell line dependent fashion and increased the fragmentation of DNA leading to accumulation of cells in Sub-G1 phase. Conclusion: In summary, results of our study demonstrated the strength of finger millet free- and bound phenolic compounds for exhibiting antioxidant property, and the potential to modulate the proliferative potential of breast and colorectal cancer cells.

Abstract Mulberry leaves are used in traditional Chinese medicine and contain numerous active substances that are known to be beneficial for human health. The aim of this study was to investigate the phenolic compositions and antioxidant activities of the leaves from 23 mulberry cultivars. Qualitative LC-ESI-QTOF analysis revealed the presence of 11 phenolic compounds in the free phenolic extracts and 10 phenolic compounds in the bound fractions. Chlorogenic acid and caffeic acid were the major components in the free and bound fractions, respectively. The results revealed that the changguosang cultivar from Taiwan contained the greatest content of phenolic compounds as well as the highest antioxidant activity among the 23 cultivars examined, as determined using three separate antioxidant assays. The isoquercitrin, chlorogenic acid, and rutin contents of the free phenolic extracts displayed significant correlations with the antioxidant activities, while syringic acid and rutin were the main contributors to the antioxidant activities of the bound phenolic fractions. The obtained results demonstrate that mulberry leaves contain a variety of beneficial phenolic substances and may be suitable for further development as a herbal medicine.

Insoluble dietary fiber (IDF) has been widely recognized for its diverse physiological activities, with increased intake being linked to a reduced risk of certain non-communicable diseases. Therefore, a comprehensive analysis of the composition, biological activity, and mechanisms of IDF is crucial for advancing its application in functional foods. There is a growing interest in the role of bound phenolics (BP) associated with IDF in the physiological activities of IDF. This review offers an overview of IDF's physiological activities, explores the interactions between BP and IDF, and discusses how BP enhance IDF's bioactivities. Mechanisms underlying the synergistic effects of IDF and BP are elucidated, and key directions for future research are proposed. IDF demonstrates various physiological activities, including oxidative stress reduction, blood glucose regulation, modulation of gut microbiota composition, and anti-inflammatory effects. The presence of BP, typically associated with IDF through covalent and noncovalent bonds, plays a pivotal role in enhancing the bioactivities of IDF. BP in IDF actively regulate intestinal flora structure and promote IDF metabolism into more short-chain fatty acids (SCFAs), which, alongside BP and metabolites, synergistically exert local or systemic biological activities. Understanding the synergistic effects of IDF and BP provides valuable insights into IDF, contributing to the development of functional dietary fiber foods and dietary interventions aimed at enhancing human health. • Insoluble dietary fiber (IDF) has diverse beneficial physiological activities. • Bound phenolics (BP) combined with IDF via covalent and noncovalent bonds. • BP enhance the bioactivities of IDF through synergistic effects. • BP in IDF work synergistically with IDF by bidirectional regulation with gut flora. [ABSTRACT FROM AUTHOR]

BACKGROUND During the thermal processing of fruit, it has been observed for phenolic compounds to either degrade, polymerize, or transfer into macromolecules. In this study, the bound and free phenolic compound composition, content, and phenolic‐related enzyme activity of lychee pulp were investigated to determine whether the free phenolic had converted to bound phenolic during heat‐pump drying (HPD). RESULTS: It was found that after HPD, when compared with the fresh lychee pulp (control), the content of bound phenolics of dried lychee pulp had increased by 62.69%, whereas the content of free phenolics of dried lychee pulp decreased by 22.26%. It was also found that the antioxidant activity of bound phenolics had also increased after drying. With the use of high‐performance liquid chromatography–tandem mass spectrometry, it was identified that (+)‐gallocatechin, protocatechuic aldehyde, isorhamnetin‐3‐O‐rutoside, 3,4‐dihydroxybenzeneacetic acid, and 4‐hydroxybenzoic acid were newly generated during HPD, when compared with the control sample. After drying, the contents of gallic acid, catechin, 4‐hydroxybenzoic acid, vanillin, syringic acid, and quercetin in bound phenolics had also increased, and polyphenol oxidase and peroxidase still showed enzyme activity, which could be related to the conversion of free phenolics to bound phenolics. CONCLUSION: Overall, during the thermal processing of lychee pulp, the free phenolics weres found to be converted into bound phenolics, new substances were generated, and antioxidant activity was increased. Hence, it was concluded that HPD improved the bound phenolics content of lychee pulp, thus providing theoretical support for the lychee processing industry. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Sizeable scientific evidence indicates the health benefits related to phenolic compounds and dietary fiber. Various phenolic compounds‐rich foods or ingredients are also rich in dietary fiber, and these two health components may interrelate via noncovalent (reversible) and covalent (mostly irreversible) interactions. Notwithstanding, these interactions are responsible for the carrier effect ascribed to fiber toward the digestive system and can modulate the bioaccessibility of phenolics, thus shaping health‐promoting effects in vivo. On this basis, the present review focuses on the nature, occurrence, and implications of the interactions between phenolics and food components. Covalent and noncovalent interactions are presented, their occurrence discussed, and the effect of food processing introduced. Once reaching the large intestine, fiber‐bound phenolics undergo an intense transformation by the microbial community therein, encompassing reactions such as deglycosylation, dehydroxylation, α‐ and β‐oxidation, dehydrogenation, demethylation, decarboxylation, C‐ring fission, and cleavage to lower molecular weight phenolics. Comparatively less information is still available on the consequences on gut microbiota. So far, the very most of the information on the ability of bound phenolics to modulate gut microbiota relates to in vitro models and single strains in culture medium. Despite offering promising information, such models provide limited information about the effect on gut microbes, and future research is deemed in this field. [ABSTRACT FROM AUTHOR]

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In this work, the spraying of ethanol solution containing phenolic acid (ferulic acid or caffeic acid) was performed before subjecting to contact ultrasound-assisted air drying of blackberry. The mass transfer modeling results revealed that sonication intensified both internal water diffusion and external water exchange during drying, and ethanol pretreatment enhanced the effective diffusivity of water. Compared with air drying alone, the drying time for sequential ferulic acid pretreatment and drying with sonication was shortened by 89.2%. Owing to the co-pigmentation between phenolic acid and anthocyanins, the retention of anthocyanins was significantly enhanced after dehydration. At the end of drying, the total anthocyanin contents in the ultrasound-dried samples pretreated with ferulic acid and caffeic acid were 25.3% and 10.5% higher than the sonicated samples without pretreatments, respectively. Furthermore, drying simultaneously with sonication promoted the preservation of non-anthocyaninic soluble phenolics including catechin, phloretic acid, rutin in blackberry compared to air drying alone. Besides, bound phenolics in blackberry were less influences by the applied dehydration treatments. This study demonstrates that the combination of phenolic acid co-pigmentation pretreatment and ultrasound drying could be a promising method to protect anthocyanin pigments during dehydration of berry fruits.

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Mulberry seeds are a byproduct of juice processing and may be an important resource for its abundant compounds. In this study, we analyzed the qualitative composition of free and bound phenolics from six varieties of mulberry seeds using UPLC-ESI-QTOF-MS/MS. Free phenolics (FPs) and bound phenolics (BPs) were measured using the Folin–Ciocalteu method; antioxidant capacity was determined by measuring 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, using the ferric reducing antioxidant power assay. A total of 28 free and 11 bound phenolics were extracted and identified, wherein five free phenolics were found in mulberry matrices for the first time. The six varieties of mulberry seeds exhibited higher content of FPs than BPs, and there was a correlation between the phenolic content and antioxidant capacity. Consequently, three varieties were selected for their high phenolic content and antioxidant capacity. This study might offer a theoretical basis for the utilization of mulberry seed.

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[Display omitted] • Bound phenolics in L. barbarum polysaccharide were first identified. • Rutin, p -coumaric acid, catechin, and ferulic acid were the main bound phenolics. • About 30% of bound phenolics were liberated from polysaccharides during digestion. • Polyphenols and polysaccharides exhibited a complex interaction during digestion. • The interaction enhanced the bioavailability of polyphenols. Polysaccharides and polyphenols are biologically active components that coexist in Lycium barbarum fruit, and there may be interactions between them that affect the release of each other. In this study, polyphenols bound to L. barbarum polysaccharide (LBP) were characterized, and the stability of bound phenolics (BP) was assessed by gastrointestinal digestion and colon fermentation. The results showed that a total of 65 phytochemicals such as flavonoids, phenolic acids, and coumarins were identified by UPLC-MS/MS. Quantitative analysis revealed that the major phenolic constituents were rutin, p -coumaric acid, catechin, ferulic acid, protocatechuic acid, and gallic acid, and their contents were 58.72, 24.03, 14.24, 13.28, 10.39, and 6.7 mg GAE/100 g DW, respectively. The release of BP by gastric digestion and gastrointestinal digestion was 9.67 % and 19.39 %, respectively. Most polyphenols were greatly affected by gastric digestion, while rutin was released in small intestine. The BP were fully released (49.77 %) and metabolized by gut microorganisms, and a considerable number of intermediates and end-products were detected, such as phloroglucinol, phenylacetic acid, and phenyllactic acid. Microbiomics data emphasized the positive impact of LBP on gut bacteria of Bacteroides , Parabacteroides , and Clostridioides. These findings could deepen our understanding of the bioavailability and biological fate of BP and also provide reference data for nutrient release and utilization of L. barbarum as a whole. [ABSTRACT FROM AUTHOR]

Polyphenols are found in free and bound forms in foods, both of which exert a wide range of pharmacological and therapeutic effects. Here, 3T3-L1 pre-adipocytes and high-fat diet (HFD)-induced mice were used to investigate the potential anti-obesity effect of bound phenolics extracted from lotus seeds (LBP). Phenolic compounds including protocatechuic, caffeic and ellagic acids were identified in LBP. In vitro results showed LBP significantly decreased intracellular lipid accumulation; while oral administration of LBP was found to retard body weight gain and improve plasma lipid profile in HFD-induced mice. Moreover, LBP increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) accompanied with down-regulation of adipogenic/lipogenic genes (Pparγ, C/ebpα, aP2, Srebp-1c, Acc1, Fas, Lpl) expression; and up-regulation of lipolytic genes (Hsl, Pgc-1α, Sirt1, Cpt1α) and adipokine adiponectin expression. Taken together, these observations suggested lotus seeds bound phenolics may alleviate obesity, in part by modulating the AMPK signaling pathway.

Diet rich in phenolics would potentially associate with multiple health benefits. Response surface methodology (RSM) was introduced to optimize the process of ultrasound- and microwave-assisted extraction of bound phenolics from the bran of a newly developed black wheat breeding line Jizi439 and then compared with the traditional alkaline method. The optimum conditions were found to be 66 °C, 48 min, and power 240 W for ultrasound-assisted extraction (UAE), and 120 s, power 420 W for microwave-assisted extraction (MAE), respectively. Total bound phenolic contents (TBPCs), determined by Folin-Ciocalteu reagent, were 8466.7 ± 240.9 μg gallic acid equivalents per gram (μg GAE/g) bran for UAE and 8340.7 ± 146.7 μg GAE/g bran for MAE under optimized conditions, which were both significantly higher than that of the traditional method (5688.9 ± 179.6 μg GAE/g) (p < 0.05). Antioxidant activities (AAs) were determined by DPPH and ABTS methods. UAE extracts showed the highest DPPH scavenging activity (77.5 ± 0.9%), while MAE extracts showed the highest ABTS scavenging activity (72.1 ± 0.6%). Both were significantly higher than that of the traditional method (69.6 ± 1.1% for DPPH and 65.9 ± 0.5% for ABTS) (p < 0.05). Total bound phenolics (TBPs) profiles were further analyzed by HPLC, and results indicated that ferulic acid was dominant, followed by vanillic acid and p-coumaric acid. The contents of each identified individual phenolics were significantly increased by ultrasound and microwave. In conclusion, UAE and MAE were comparable with each other in TBP yields and AAs; however, when taking operation time and energy consumption into consideration, MAE was more efficient than UAE. Our study suggested efficiency extraction methods for further use of bound phenolics as a healthy food ingredient.

Mulberry leaves are used in traditional Chinese medicine and contain numerous active substances that are known to be beneficial for human health. The aim of this study was to investigate the phenolic compositions and antioxidant activities of the leaves from 23 mulberry cultivars. Qualitative LC-ESI-QTOF analysis revealed the presence of 11 phenolic compounds in the free phenolic extracts and 10 phenolic compounds in the bound fractions. Chlorogenic acid and caffeic acid were the major components in the free and bound fractions, respectively. The results revealed that the changguosang cultivar from Taiwan contained the greatest content of phenolic compounds as well as the highest antioxidant activity among the 23 cultivars examined, as determined using three separate antioxidant assays. The isoquercitrin, chlorogenic acid, and rutin contents of the free phenolic extracts displayed significant correlations with the antioxidant activities, while syringic acid and rutin were the main contributors to the antioxidant activities of the bound phenolic fractions. The obtained results demonstrate that mulberry leaves contain a variety of beneficial phenolic substances and may be suitable for further development as a herbal medicine. [ABSTRACT FROM AUTHOR]

Background and objectives: Health benefits of cereals depend not only on the intake levels but also on their processing methods and conditions. In this work, effects of processing treatments, including steaming, cooking, and roasting on the free and bound phenolics content and antioxidant properties of mung bean, were investigated. Findings: The free phenolics content of mung bean significantly decreased (p <.05), while the bound phenolics content significantly increased after processing. The loss in the free phenolics content was found to be greater after cooking, followed by steaming, and roasting. However, cooked mung bean samples showed greater bound phenolics content than that of steamed or roasted ones. Antioxidant activity of mung bean phenolics retained or even enhanced after processing depending processing method, duration, and temperature as well as phenolics type, that is, free and bound. Furthermore, a positive correlation was found between the free or bound phenolics content and antioxidant activity of mung bean. Conclusions: The processing of whole mung bean grain resulted in the change of the composition content of phenolics and changed the antioxidant activity. It was feasible to maintain the active by adjusting the processing mode and conditions of grain. Significance and novelty: The antioxidant activity modification promoted by the processing treatment could increase the potential applications of mung bean. [ABSTRACT FROM AUTHOR]

Durum wheat and rice brans are by-products deriving from the milling industry and source of important phytochemicals, mostly phenolics in bound form. The objectives of this work were to evaluate the most effective method for the extraction of phenolic acids from these by-products with antioxidant and antimicrobial activity and to standardize the obtained extracts to encourage their commercialization in health field. Free phenolics were extracted with ultrasound-assisted extraction (UAE) and bound phenolics with alkaline hydrolysis (AH) and ultrasound-assisted alkaline hydrolysis (UAAH). Extracts were analyzed with HPTLC (high-performance thin-layer chromatography) and RPHPLC-DAD-ESIMS (reversed-phase high-performance liquid chromatography-diode array detector-electrospray ionization mass spectrometry); the content of trans-ferulic acid, p-coumaric acid, total phenolics were also quantified. The antioxidant activity was investigated using DPPH and ABTS methods. The antimicrobial activity was evaluated against Staphylococcus aureus and Staphylococcus epidermidis strains. Results obtained using UAAH showed the most interesting data, suggesting this method as the most effective to obtain active extracts from the by-products. Durum wheat, extracted with UAAH, exhibited the highest content of trans-ferulic acid (406.14 ± 0.65 ji,g FA/mg extract), total phenolics (610.58 ± 57.60 mg GAE/g dried extract) and good antioxidant and antimicrobial activities and it has been selected to formulate oil-in-water cosmetic products. [ABSTRACT FROM AUTHOR]

The phytochemical composition and antioxidant activity of fruits are associated with their health benefits. Longan is a traditional Chinese edible and medicinal fruit, but its varietal differences in phytochemical profiles and antioxidant activity were unknown. Twenty-four longan cultivars from southern China were investigated in this study. Their total phenolic and flavonoid contents in pulp were 22.09–132.47 mg gallic acid equivalents/100 g and 2.48–14.26 mg catechin equivalents/100 g, respectively. The mean contributions of free phenolics and flavonoids to the total were 82.5% and 94.0%, respectively. Among 10 individual phenolics detected by HPLC, the contents of epicatechin, 4-methylcatechol, chlorogenic, and vanillic acids were relatively higher. The cellular antioxidant activity (CAA) of longan pulp showed significant varietal discrepancies and positive correlation with phenolic and flavonoid contents. Phenolics in longan pulp of 24 cultivars showed lower CAA potential than many other fruits with the CAA qualities from 0.35 to 1.21 µmol quercetin equivalent/100 µmol total phenolics. Longan cultivars were classified into six groups by hierarchical clustering analysis. Six cultivars in group 4 and 6 had higher phytochemical contents and CAA activity.

The extraction of ferulic acid (FA) and other phenolic compounds from wheat bran can represent an interesting valorization step of this lignocellulosic biomass. In this work, pressurized hot water (PHW) and pressurized aqueous ethanol are used as solvents, and the amount of extracted FA in its free form and the total phenolic content of the extract have been evaluated. Total ferulic acid in the initial wheat bran was 2570.9 ± 1.8 µg/g of dry bran, being more than 98.5% esterified to arabinoxylans and other cell wall structures (insoluble-bound FA). Different concentrations of ethanol in water (0–20–50–80%), temperatures (130–145–160 °C) and extraction times (20–40–60 min) were tested. It was observed that low ethanol concentrations in the solvent, high temperatures and long extraction times favored the extraction, being the hydrolysis and not the solvolysis the reaction mechanism involved in the release of bound FA. Maximum FA extraction yield was found for pure water (PHW), 160 °C and 74 min of extraction that corresponds to a thermal severity factor of log (R0) ≈ 3.7. The so obtained FA extraction yields are higher than those obtained with an enzymatic hydrolysis treatment performed for comparison. [ABSTRACT FROM AUTHOR]

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Ｉｎ ｏｒｄｅｒ ｔｏ ｅｘｐｌｏｒｅ ｔｈｅ ｍａｒｋｅｔ ｖａｌｕｅ ｏｆ ｂｌａｃｋ ｔａｒｔａｒｙ ｂｕｃｋｗｈｅａｔ, ｗｅ ａｎａｌｙｚｅｄ ｔｈｅ ｐｈｅｎｏｌｉｃｓ ａｎｄ ａｎｔｉｏｘｉｄａｎｔ ａｃｔｉｖｉｔｉｅｓ ｏｆ Ｃｈｕａｎｑｉａｏ １ ａｎｄ Ｊｉｕｊｉａｎｇ Ｋｕｑｉａｏ, ｔｗｏ ｔａｒｔａｒｙ ｂｕｃｋｗｈｅａｔ ｖａｒｉｅｔｉｅｓ ｐｌａｎｔｅｄ ｉｎ ｔｈｅ ｌｏｗ-ｅｌｅｖａｔｉｏｎ ｒｅｇｉｏｎｓ ｏｆ ｔｈｅ Ｊｉａｎｇｈａｎ Ｐｌａｉｎ ｏｆ Ｈｕｂｅｉ, ｄｅｔｅｒｍｉｎｅｄ ｔｈｅ ｃｏｎｔｅｎｔｓ ｏｆ ｆｒｅｅ, ｂｏｕｎｄ ａｎｄ ｔｏｔａｌ ｐｈｅｎｏｌｉｃｓ ａｎｄ ｆｌａｖｏｎｏｉｄｓ, ａｎｄ ｗｅ ａｎａｌｙｚｅｄ ｔｈｅ ａｎｔｉｏｘｉｄａｎｔ ａｃｔｉｖｉｔｉｅｓ ｏｆ ｔｈｅｉｒ ｓｅｅｄ ｅｘｔｒａｃｔｓ ｉｎ ｖｉｔｒｏ ｕｓｉｎｇ ｔｈｅ ＤＰＰＨ ｆｒｅｅ ｒａｄｉｃａｌ, ＡＢＴＳ ｆｒｅｅ ｒａｄｉｃａｌ ａｎｄ ｉｒｏｎ ｉｏｎ ｒｅｄｕｃｔｉｏｎ ａｎｔｉｏｘｉｄａｎｔ (ＦＲＡＰ) ａｓｓａｙｓ, ａｎｄ ｗｅ ａｌｓｏ ｄｅｔｅｒｍｉｎｅｄ ｔｈｅ ｐｈｅｎｏｌｉｃ ｃｏｍｐｏｓｉｔｉｏｎｓ ｏｆ ｔｈｅ ｓｅｅｄ ｅｘｔｒａｃｔｓ ｂｙ ｔｈｅ ｈｉｇｈ ｐｅｒｆｏｒｍａｎｃｅ ｌｉｑｕｉｄ ｃｈｒｏｍａｔｏｇｒａｐｈｙ (ＨＰＬＣ). Ｔｈｅ ｒｅｓｕｌｔｓ ｗｅｒｅ ａｓ ｆｏｌｌｏｗｓ: (１) Ｔｈｅ ｃｏｎｔｅｎｔｓ ｏｆ ｔｏｔａｌ ｐｈｅｎｏｌｉｃｓ ａｎｄ ｔｏｔａｌ ｆｌａｖｏｎｏｉｄｓ ｗｅｒｅ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｉｎ ｔｈｅ ｓｅｅｄｓ ｏｆ Ｃｈｕａｎｑｉａｏ １ ｔｈａｎ ｔｈｏｓｅ ｏｆ Ｊｉｕｊｉａｎｇ Ｋｕｑｉａｏ, ｗｉｔｈ ｔｈｅ ｆｏｒｍｅｒ ｓｔａｎｄｉｎｇ ａｔ ２７.３８ ｍｇ ＧＡＥ􀅰ｇ-１ ＤＷ ａｎｄ ３１.４６ ｍｇ ＲＥ􀅰ｇ-１ ＤＷ ａｎｄ ｔｈｅ ｌａｔｔｅｒ ａｔ １２.７１ ｍｇ ＧＡＥ􀅰ｇ-１ ＤＷ ａｎｄ １４.６８ ｍｇ ＲＥ􀅰ｇ-１ ＤＷ ; ｉｎ ｔｈｅ ｓｅｅｄｓ ｏｆ ｔｈｅ ｔｗｏ ｖａｒｉｅｔｉｅｓ, ｔｈｅ ｃｏｎｔｅｎｔｓ ｏｆ ｔｈｅ ｆｒｅｅ ｐｈｅｎｏｌｉｃｓ ａｎｄ ｆｌａｖｏｎｏｉｄｓ, ｗｈｉｃｈ ｍａｄｅ ｕｐ ｍｏｒｅ ｔｈａｎ ７９％ ｏｆ ｔｈｅ ｔｏｔａｌ ｐｈｅｎｏｌｉｃｓ ａｎｄ ｆｌａｖｏｎｏｉｄｓ, ｗｅｒｅ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｔｈａｎ ｔｈｏｓｅ ｏｆ ｂｏｕｎｄ ｐｈｅｎｏｌｉｃｓ ａｎｄ ｆｌａｖｏｎｏｉｄｓ; ｔｈｅ ｃｏｎｔｅｎｔｓ ｏｆ ｂｏｕｎｄ ｐｈｅｎｏｌｉｃｓ ａｎｄ ｆｌａｖｏｎｏｉｄｓ ｗｅｒｅ ｈｉｇｈｅｒ ｉｎ ｔｈｅ ｓｅｅｄｓ ｏｆ Ｊｉｕｊｉａｎｇ Ｋｕｑｉａｏ ｔｈａｎ ｔｈｏｓｅ ｏｆ Ｃｈｕａｎｑｉａｏ １. (２) Ｒｕｔｉｎ, ｑｕｅｒｃｅｔｉｎ, ｅｐｉｃａｔｅｃｈｉｎ, ｋａｅｍｐｆｅｒｏｌ, ｋａｅｍｐｆｅｒｏｌ-３-ｒｕｔｉｎｏｓｉｄｅ ａｎｄ ｑｕｅｒｃｅｔｉｎ-３-Ｏ-ｒｕｔｉｎｏｓｉｄｅ- ３′-Ｏ-ｇｌｕｃｏｐｙｒａｎｏｓｉｄｅ ｄｏｍｉｎａｔｅｄ ａｍｏｎｇ ｔｈｅ ｐｈｅｎｏｌｉｃ ｃｏｍｐｏｕｎｄｓ ｉｎ ｔｈｅ ｓｅｅｄｓ ｏｆ ｔｈｅ ｂｌａｃｋ ｔａｒｔａｒｙ ｂｕｃｋｗｈｅａｔ ｖａｒｉｅｔｉｅｓ, ｗｉｔｈ ｒｕｔｉｎ ａｎｄ ｑｕｅｒｃｅｔｉｎ ｄｏｍｉｎａｎｔ ｐｈｅｎｏｌｉｃｓ ａｍｏｎｇ ｔｈｅ ｆｒｅｅ ｐｈｅｎｏｌｉｃ ｃｏｍｐｏｕｎｄｓ ａｎｄ ｅｐｉｃａｔｅｃｈｉｎ ａｎｄ ｒｕｔｉｎ ｄｏｍｉｎａｎｔ ａｍｏｎｇ ｔｈｅ ｂｏｕｎｄ ｏｎｅｓ. (３) Ａｌｌ ｔｈｅ ｓｅｅｄ ｅｘｔｒａｃｔｓ ｏｆ ｔｈｅ ｔａｒｔａｒｙ ｂｕｃｋｗｈｅａｔ ｖａｒｉｅｔｉｅｓ ｐｒｅｓｅｎｔｅｄ ａｎｔｉｏｘｉｄａｎｔ ａｃｔｉｖｉｔｉｅｓ ａｎｄ ｔｈｅ ａｎｔｉｏｘｉｄａｎｔ ａｃｔｉｖｉｔｉｅｓ ｏｆ ｔｈｅ ｆｒｅｅ ｓｅｅｄ ｅｘｔｒａｃｔｓ ｏｆ Ｃｈｕａｎｑｉａｏ １, ｄｅｔｅｒｍｉｎｉｎｇ ａｓ ｂｅｉｎｇ ３０.１４, １１.０３ ａｎｄ １８.８４ ｍｇ ＴＥ􀅰ｇ-１ ＤＷ ｕｓｉｎｇ ＤＰＰＨ, ＡＢＴＳ ａｎｄ ＦＲＡＰ, ｒｅｓｐｅｃｔｉｖｅｌｙ, ｗｅｒｅ ｈｉｇｈｅｒ ｔｈａｎ ｔｈｏｓｅ ｏｆ Ｊｉｕｊｉａｎｇ Ｋｕｑｉａｏ. Ｔｈｅ ａｎｔｉｏｘｉｄａｎｔ ａｃｔｉｖｉｔｉｅｓ ｏｆ ｔｈｅ ｂｏｕｎｄ ｅｘｔｒａｃｔｓ ｏｆ Ｃｈｕａｎｑｉａｏ １ ｗｅｒｅ ｌｏｗｅｒ ｔｈａｎ ｔｈｏｓｅ ｏｆ Ｊｉｕｊｉａｎｇ Ｋｕｑｉａｏ, ｂｕｔ ｔｈｅ ｔｏｔａｌ ａｎｔｉｏｘｉｄａｎｔ ａｃｔｉｖｉｔｙ ｏｆ ｔｈｅ ｆｏｒｍｅｒ ｖａｒｉｅｔｙ ｗａｓ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｔｈａｎ ｔｈａｔ ｏｆ ｔｈｅ ｌａｔｔｅｒ ｏｎｅ. Ｔｈｅｒｅｆｏｒｅ, ｐｌａｎｔｅｄ ｉｎ ｌｏｗ-ｅｌｅｖａｔｉｏｎ ｒｅｇｉｏｎｓ ｏｆ ｔｈｅ Ｊｉａｎｇｈａｎ Ｐｌａｉｎ, Ｃｈｕａｎｑｉａｏ １ ｈａｄ ｈｉｇｈｅｒ ｃｏｎｔｅｎｔｓ ｏｆ ｓｅｅｄ ｐｈｅｎｏｌｉｃ ｃｏｍｐｏｕｎｄｓ, ａｓ ｂｅｉｎｇ ｒｅｑｕｉｒｅｄ ｉｎ ｓｕｂｓｅｑｕｅｎｔ ｆｏｏｄ ｐｒｏｃｅｓｓｉｎｇ ａｎｄ ｐｒｅｓｅｎｔｉｎｇ ａ ｂｒｉｇｈｔ ｍａｒｋｅｔ ｐｒｏｓｐｅｃｔ. [ABSTRACT FROM AUTHOR]

BACKGROUND: Tomato is one of the most important agricultural crops and it is characterized by a wide bioactive compound profile. However, little information is reported on its comprehensive polyphenol profile. In this work, 13 commercial tomato cultivars for industrial transformation were screened by ultra‐high‐pressure liquid chromatography coupled to quadrupole‐time‐of‐flight mass spectrometry (UHPLC‐QTOF‐MS) for both free and bound phenolic profiles. Thereafter, the in vitro antioxidant activity of each cultivar was assessed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance activity (ORAC) assays. Multivariate statistics, i.e. orthogonal projection to latent structures discriminant analysis (OPLS‐DA), were then used to model samples according to their distinct phenolic signatures, thus providing compounds that better discriminated between the distributions of the cultivars that were considered. RESULTS: More than 350 phenolic compounds could be identified across the samples that were considered: flavonoids (such as flavones and flavanols), hydroxycinnamic acids, lignans, and lower‐molecular‐weight phenolics were the most frequently observed classes of phenolics in tomato berries. Anthocyanins were the most abundant class among bound phenolics (being highest in the Leader F1 and Defender F1 cultivars), followed by tyrosols (mainly in Heinz cultivars). However, flavones and hydroxybenzoic acids were the most represented discriminant phenolics in the bound fraction. CONCLUSIONS: Untargeted metabolomics allowed significant differences in phenolic composition to be outlined across the tomato cultivars that were analyzed. Such differences were particularly evident regarding the free‐to‐bound phenolic ratio, hence allowing differences in the bioaccessibility of phenolics to be postulated. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Bound phenolics are the main phytochemicals and important contributors to the health benefits of whole grains. The commonly used chemical methods for bound phenolic release are not appropriate for processing of food materials. The effects of cellulase and feruloyl esterase on releasing bound phenolics from rice bran dietary fibre (RBDF) and the auxiliary effects of autoclaving pretreatment were investigated in the present study to find a method to effectively increase bioaccessible phenolics in RBDF. The results showed that cellulase (CT) and feruloyl esterase (FT) alone and combined application (CFT) released limited bound phenolics. Autoclaving pretreatment could enhance the release of bound phenolics by enzymatic treatments significantly with 1.74, 5.56 and 1.76 folds increases when compared with the above mentioned enzymolysis, respectively. Moreover, the total quantity of phenolic compounds released from RBDF via combined enzymolysis of cellulase and feruloyl esterase with autoclaving pretreatment (A-CFT) were comparable with that via alkaline hydrolysis previously reported. The predominant phenolic compounds released by A-CFT from RBDF were vanillin and ferulic acid, while ferulic and p -couramic acids accounted for 99.30% of the sum of phenolics released by alkaline hydrolysis. The DPPH scavenging, FRAP and ORAC antioxidant activities of the enzymatic hydrolysates were positive correlated with their total phenolic contents. The phenolics released by A-CFT showed lower antioxidant activity than those by alkaline hydrolysis, which may ascribe to the difference in phenolic profiles between methods. This study provides a new approach for processing whole grain and the by-products for functional foods materials with higher phenolic bioaccessibility. [Display omitted] • Enzymolysis releasesa small part of bound phenolics from rice bran fiber (RBDF). • Autoclaving greatly increases the released bound phenolics via enzymolysis from RBDF. • Phenolics released by enzymolysis are different in composition from alkaline hydrolysis. [ABSTRACT FROM AUTHOR]

Pitahaya peel is a good source of bioactive polyphenols. However, the bound phenolics and their antioxidant activity remain unclear. The bound phenolics of pitahaya peel from two red-skinned species with red pulp (RP) and white pulp (WP) were released with different methods (acid, base, and composite enzymes hydrolysis). The results revealed that base hydrolysis was the most efficient method for releasing the bound phenolics from RP (11.6 mg GAE/g DW) and WP (10.5 mg GAE/g DW), which was 13.04-fold and 8.18-fold for RP and 75.07-fold and 10.94-fold for WP compared with acid hydrolysis and enzymatic hydrolysis, respectively. A total of 37 phenolic compounds were identified by UPLC-TOF/MS with most chlorogenic acid, caffeic acid, ferulic acid and p-coumaric acid in RP, whereas chlorogenic acid, caffeic acid, ferulic acid, rutin and isoquercitrin were the main compounds in WP. Regardless of the hydrolysis method, the extracts having the highest phenolic content showed the strongest antioxidant activities. The work shows that hydrolysis methods have a significant effect on the release of phenolics, and the contents of major characteristic bound phenolic compounds are related to the ecological type of pitahaya.

Both extractable (EPE) and non-extractable bound phenolic (BPE) in the seed coat and cotyledon of black bean were investigated in the present study. Their total phenolic contents (TPC) and antioxidant activities (DPPH, ABTS and FRAP) were evaluated, and the phytochemical compositions of EPE and BPE in both seed coat and cotyledon of black soybean were identified and quantified (Glycinemax(L.) merr) by UPLC-ESI-QTOF-MS/MS and UPLC-ESI-QqQ-MS/MS. In the present study, a total of 112 and 78 compounds were identified or tentatively characterized in the black soybean EPE and BPE, respectively, with the majority being phenolic acids and flavonoids. Seed coat contains more abundant phenolics than that of cotyledon in all fractions. In addition, our results indicated that acid hydrolysis is more thorough than alkaline hydrolysis in the extraction of bound phenolics of black soybean. Our study provides available information for non-extractable bound phenolic constituents and their distribution in the seed coat and cotyledon of black soybean.

The intracellular antioxidant activities of millet, rice, wheat, brown rice, oat, buckwheat, corn and adlay phenolic extracts were evaluated in an ex vivo erythrocytes system. Buckwheat, corn, and brown adlay free phenolic extracts could effectively attenuate H2O2-induced erythrocyte hemolysis. The protective effects and involved mechanisms of polished adlay, brown adlay and adlay bran phenolic extracts were studied further. The intracellular antioxidant activities of adlay phenolic extracts decreased in the following order: adlay bran > brown adlay > polished adlay. Adlay bran free phenolic extract possessed stronger intracellular antioxidant activity than chlorogenic acid, p-coumaric acid and ferulic acid. The free phenolic extracts were more effective than bound phenolic extracts to suppress hemolysis and plasma oxidation through inhibition of MDA equivalents, MetHb and ROS generation and to restore the activities of Na+K+-ATPase, Ca2+Mg2+-ATPase and intracellular antioxidant enzyme to normal levels. Adlay-rich diets could reduce the incidence of cancer, cardiovascular and neurodegenerative diseases.

In this review, the properties of bound (unextractable) phenolic compound forms in food structure, protein-phenolic and carbohydrate-phenolic relationships, metabolism and bioavailability in digestion are discussed. Phenolic compounds in foods are determined by conventional methods using organic solvents. However, bound forms which remain in the extraction residue and constitute a significant portion of the total phenolic compounds are ignored. Therefore, the total phenolic content of foods, especially those with high phenolic content, has not been accurately determined in the past. Bound phenolic compounds which account for 20-60% of the total phenolic content of fruit, vegetables, cereals and legumes are now taken into account in determining the phenolic composition. Bound phenolics can be covalently attached to the cell wall by structures such as cellulose, pectin, protein by ester, ether or acetal bonds. Due to their aromatic rings and hydroxyl groups, phenolic compounds have the ability to bind to the cell wall and to structures such as protein, carbohydrate, lipid by hydrophobic and hydrophilic interactions, hydrogen and covalent bonds. There are many factors in the interaction of phenolics with macromolecules such as molecular weight, degree of polymerization, and number of aromatic groups. This complex is known to have many positive effects on human health. The bioavailability of phenolic compounds in foods depends on their release, absorption and passage into the bloodstream during digestive or intestinal fermentations. In particular, polyphenols in certain foods bind to macromolecules such as proteins, carbohydrates, lipids in the cell wall structure and greatly affect the bioavailability of the gastrointestinal tract. Due to the difficult digestion of cell wall materials, bound phenolic compounds can reach the colon without alteration in the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

The phenolic-profiling of seven different wheat (Triticum aestivum) genotypes was investigated for the first time during different stages of grain development (milky, softy, physiological maturity and mature). Free and bound phenolic compounds were extracted separately and analyzed by UPLC-QTOF-MSE. Total phenolic content significantly decreased, up to 50% depending on the genotype, towards the maturation of grain. The highest content (free and bound) was observed in the most immature grains, while the lowest level was found in mature grains (408.0 and 165.0 GAE mg/100 g, respectively). Globally, 237 phenolic compounds were identified, divided into 5 classes: flavonoids (85), phenolic acids (77), other polyphenols (51), lignans (16) and stilbenes (8). UPLC-MS results showed a progressively decrease of the number of phenolic identification (ID) all along grain development, milky (213), softy (192), physiological maturity (169) and mature (144). The proportion bound to free phenolic progressively increased, reaching the maximum at physiological maturity, indicating a possible enzymatic reactions and complexation during grain growth. Ferulic acid, diphyllin, 4-hydroxybenzoic acid, ferulic acid isomer, apigenin 7-O-apiosyl-glucoside isomer and myricetin isomer were the most abundant compounds. Chemometric tools showed a clear separation between immature and mature grain for all genotypes. Phenolic profile varied significantly among genotypes, this result can help the selection of varieties towards a higher retention of bioactive compounds. Noteworthy, immature wheat grains can be considered a rich source of phenolic compounds and as an attractive ingredient to incorporate to functional foods. Unlabelled Image • Phenolic profile of 7 genotypes of immature and mature wheat was studied by UPLC-MS. • 237 phenolics including isomers were tentatively identified as free and bound forms. • Immature grains presented the highest abundance of phenolics than mature grains. • Phenolic profiles are different among genotypes and during the grain development. • Brazilian wheat showed a rich composition and abundance of phenolic compounds. [ABSTRACT FROM AUTHOR]