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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]

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]

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.

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.

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.

[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]

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.

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]

Chestnut rose (Rosa roxburghii Tratt.) is an underutilized plant in the Rosaceae family that originates from southwest of China. This study used UHPLC-IM-QTOF and UPLC-QQQ to analyze the free and bound phenolic fractions in three cultivars of chestnut rose fruit from different producing areas. The optimization of IM feature acquisition was conducted firstly. Then, 23 phenolics were reported in chestnut rose fruit for the first time. Differential phenolics profiles were observed between cultivars and fractions, with 24 phenolics further quantified. Catechin, procyanidin B1, gallic acid, ellagic acid and isoquercitrin were the five most abundant phenolics. Most of the phenolics were more abundant in the free fraction than in the bound fraction. As many phenolics were reported with functions such as antioxidant, antidiabetic and anti-cancer, the chestnut rose fruit could serve as a healthy functional supplement foods in the form of juice, oral solution and powder, as well as an ingredient for functional foods. • Free and bound phenolics from three cultivars of chestnut rose fruit were analyzed. • Twenty-three phenolics were reported in chestnut rose fruit for the first time. • Twenty-four phenolics were quantified in chestnut rose fruit. • Most phenolics were more abundant in free fraction than bound fraction. • Catechin, procyanidin B1, gallic acid, ellagic acid and isoquercitrin were rich. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of the lychee pulp-derived dietary fiber-bound phenolic complex (DF-BPC) on a murine model of loperamide-induced constipation and its molecular mechanism associated with gut microbiota modification. DF-BPC supplementation mitigated loperamide-induced dyschezia, intestinal hypomotility, and colonic impairment, as evidenced by the increased gastro-intestinal transit rate and mucus cell counts. By comparison, short-chain fatty acids (SCFAs) contents and relative abundances of associated genera ( Butyricimonas , Clostridium, and Lactobacillus ) were effectively upregulated following DF-BPC supplementation. Notably, DF-BPC significantly enhanced expressions of G protein-coupled receptor (GPR) 41 and 43, reaching 1.43- and 1.62-fold increase, respectively. Neurotransmitter secretions were simultaneously altered in DF-BPC-treated mice, suggesting upregulation of the SCFAs-GPRs-enteric nervous system pathway. The overexpression of aquaporins (AQP3, 8, and 9) was stimulated partly through GPRs activation. Mild inflammation associated with constipation was inhibited by suppressing LBP-TLR4-NF-κB signaling translocation. These findings suggest that DF-BPC from lychee pulp has the potential to alleviate constipation in mice through modifying the gut microbiome.

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 (IC 50 ) 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., Competing Interests: Conflict of interestThe authors report no conflicts of interest., (© The Korean Society of Food Science and Technology 2022, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

[Display omitted] • Affinity-ultrafiltration strategy was used to figure α-glucosidase inhibitors. • 7 potential α-glucosidase inhibitors were identified from brown rice. • The type of inhibition of the inhibitors against α-glucosidase were measured. • The inhibitory mechanisms of 7 inhibitors were studied by molecular simulation. Brown rice bound phenolics extracts (BRBPE) have been reported to possess α-glucosidase inhibitory effects, the specific enzyme inhibitors involved in this process were unknown. Here, α-glucosidase inhibitors in BRBPE were screened using bioaffinity ultrafiltration methods, and seven phenolic compounds – three monomers (p -coumaric acid, ferulic acid and methyl ferulate), three dimers (8-5′, 5-5′ and 8- O -4′ diferulic acid) and a trimer (5-5′/8- O -4″ dehydrotriferulic acid) were identified as exact inhibitors, among which 5-5′/8- O -4″ dehydrotriferulic acid and 5-5′diferulic acid exhibited the best inhibitory activity. Enzyme kinetic analysis suggested that the inhibitory mechanism of these seven inhibitors including competitive, noncompetitive, uncompetitive and mixed manner. Molecular docking analysis revealed that the seven inhibitors bind with α-glucosidase mainly by hydrogen bonding interaction, hydrophobic force and ionic bond. Molecular dynamics simulation further explored the structure and molecular property of phenolic-glucosidase complex. This work provided a deep insight into brown rice bound phenolics acting as potent α-glucosidase inhibitors. [ABSTRACT FROM AUTHOR]

Phenolic compounds (PC) strongly contribute to the beneficial health effects of wheat, but their interactions can affect the quality of end-use wheat products. Free and bound PC were comprehensively characterized in 14 wheat flours (Triticum aestivum) from different Brazilian genotypes and technological qualities by using a metabolomics approach (UPLC-ESI-QTOF-MSE) combined with classical characterizations: colorimetry, ash, protein, starch and total phenolic content (TPC). Globally, 43 PC were identified: 33 (bound, 28 (free) and 15 in all flours, regardless of extract. Ferulic acid isomers were the most abundant PC, representing 25–50% of ion abundance depending on genotype. Campeiro, Sossego and Topázio genotypes showed a distinguished profile, with the highest total relative abundance of PC. TPC was significantly higher in flours with higher gluten strength (66.5–58.0 mg GAE/100 g flour). The ratio free-to-bound of PC averaged 1.15 between the flours of different technological qualities. Although PCA highlighted specific PC related to technological qualities, the genotype effect was very pronounced. This study correlates the phenolic profile and technological quality of wheat flours and provides the most recent data on the secondary metabolites profile, especially PC in refined flour, attesting to its significant nutritional importance due to its large consumption in refined forms. [Display omitted] • First study to correlate phenolic profile and technological quality in Brazilian wheat flours. • Metabolomics reveals the phenolic profile in different Brazilian genotypes in wheat flours. • Phenolic compounds persist after the milling process in refined wheat flours. • Twenty phenolic compounds were detected in all genotypes studied. • Multivariate analysis highlighted discriminating compounds among the technological qualities. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-pigmentation pretreatment protected blackberry anthocyanins during drying. • Ethanol pretreatment with phenolic acids only enhanced water effective diffusivity. • Non-anthocyaninic soluble phenolics were better preserved under contact sonication. • Bound phenolics were less affected by pretreatments and ultrasound-assisted drying. 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. [ABSTRACT FROM AUTHOR]

[Display omitted] • 4 new and 18 known compounds were isolated from brown rice bound phenolic extracts. • Three known phenolic compounds were reported from brown rice for the first time. • The contents of 22 compounds in brown rice, bran and polished rice were determined. • The ORAC, PSC, and CAA antioxidant activity of isolated compounds were measured. Chemical profiles, distribution, and antioxidant activity of bound phenolics from brown rice were investigated. Four new dehydrodiferulic acid dimers (DFA) along with eighteen known phenolics were isolated from brown rice bound phenolic extracts and their structures were determined by multiple spectroscopic methods. Among them, ferulic acid and 8–5′ DFA were the most abundant monomeric and dimeric bound phenolics in brown rice, rice bran and polished rice. In whole brown rice, polished rice contributed more than 50% of three phenolic monomers and six phenolic dimers, while rice bran contributed more than half of the other thirteen phenolics including eight monomers, four dimers, and one trimer. All the isolated compounds exhibited oxygen radical absorbance capacity. Thomasidioic acid, caffeic acid, methyl caffeate, and 8–5′ DC DFA displayed potent peroxyl radical scavenging capacity, and the last three compounds also showed moderate cellular antioxidant activity. [ABSTRACT FROM AUTHOR]