Chemical profile and antioxidant potential of extractable and non‐extractable polyphenols in commercial teas at different fermentation degrees

Nonextractable Polyphenols from Fu Brick Tea Alleviates Ulcerative Colitis by Controlling Colon Microbiota-Targeted Release to Inhibit Intestinal Inflammation in Mice

This study was designed to elucidate the colon microbiota-targeted release of nonextractable bound polyphenols (NEPs) derived from Fu brick tea and to further identify the possible anti-inflammatory mechanism in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice. 1.5% DSS drinking water-induced C57BL/6J mice were fed rodent chow supplemented with or without 8% NEPs or dietary fibers (DFs) for 37 days. The bound p-hydroxybenzoic acid and quercetin in NEPs were liberated up to 590.5 ± 70.6 and 470.5 ± 51.6 mg/g by in vitro human gut microbiota-simulated fermentation, and released into the colon of the mice supplemented with NEPs by 4.4- and 1.5-fold higher than that of the mice supplemented without NEPs, respectively (p < 0.05). Supplementation with NEPs also enhanced the colonic microbiota-dependent production of SCFAs in vitro and in vivo (p < 0.05). Interestingly, Ingestion of NEPs in DSS-induced mice altered the gut microbiota composition, reflected by a dramatic increase in the relative abundance of Dubosiella and Enterorhabdus and a decrease in the relative abundance of Alistipes and Romboutsia (p < 0.05). Consumption of NEPs was demonstrated to be more effective in alleviating colonic inflammation and UC symptoms than DFs alone in DSS-treated mice (p < 0.05), in which the protective effects of NEPs against UC were highly correlated with the reconstruction of the gut microbiome, formation of SCFAs, and release of bound polyphenols. These findings suggest that NEPs as macromolecular carriers exhibit targeted delivery of bound polyphenols into the mouse colon to regulate gut microbiota and alleviate inflammation.

Unlocking peach juice byproduct potential in food waste biorefineries: Phenolic compounds profile, antioxidant capacity and fermentable sugars

This work assesses an integrated pathway for the revalorization of peach byproduct (PB) within a biorefinery. PB was subjected to an oven-drying (OD) treatment for its evaluation as a storage treatment. It was compared to freeze-drying and untreated material in terms of antioxidant capacity (AOC), phenolic compounds (PC) profile and fermentable sugar production. OD reduced the water content to less than 15 % while preserving the bound hydrolysable polyphenols, which were the more abundant PC (≈64 %) with the highest AOC. Drying treatments hampered polysaccharide accessibility, but some enzyme preparations released 60-70 g/L of fermentable sugars at relatively high solids loading (10 %). This study proposes a novel enzyme-based strategy for the valorisation of fermentable sugars and antioxidant compounds from PB. The sugars can be fermented into several building blocks while the solid residue enriched in recalcitrant phenolic compounds and proteins could be used to develop novel functional products for food/feed sectors.

Colon-Targeted Release of Turmeric Nonextractable Polyphenols and Their Anticolitis Potential via Gut Microbiota-Dependent Alleviation on Intestinal Barrier Dysfunction in Mice

Solid evidence has emerged supporting the role of nonextractable polyphenols (NEPs) and dietary fibers (DFs) as gut microbiota modulators. This study aims to elucidate gut microbiota-dependent release of turmeric NEPs and examine the possible anti-inflammatory mechanism in the dextran sulfate sodium-induced ulcerative colitis (UC) model. 1.5% DSS drinking water-induced C57BL/6J mice were fed a standard rodent chow supplemented with or without 8% extractable polyphenols (EPs), NEPs, or DFs for 37 days. The bound curcumin, demethoxycurcumin, and bisdemethoxycurcumin in NEPs were released up to 181.5 ± 10.6, 65.2 ± 6.0, and 69.5 ± 7.6 μg/mL by in vitro gut microbiota-simulated fermentation and released into the colon of NEP-supplemented mice by 5.7-, 11.0-, and 7.8-fold higher than pseudo germ-free mice, respectively (p < 0.05). NEPs also enhanced the colonic microbiota-dependent production of short-chain fatty acids in vitro and in vivo (p < 0.05). Interestingly, NEP feeding significantly improved the DSS-caused gut microbiota disorder, epithelial barrier damage, and inflammation of UC mice better than EPs or DFs (p < 0.05). Meanwhile, the pseudo germ-free mice supplemented with NEPs failed to ameliorate UC symptoms. These findings manifest that turmeric NEPs as macromolecular carriers exert the target delivery of polyphenols into the colon for regulating gut microbiota to restore the impaired gut barrier function for alleviation of inflammation.

Electronic Sensor Technologies in Monitoring Quality of Tea: A Review

Tea, after water, is the most frequently consumed beverage in the world. The fermentation of tea leaves has a pivotal role in its quality and is usually monitored using the laboratory analytical instruments and olfactory perception of tea tasters. Developing electronic sensing platforms (ESPs), in terms of an electronic nose (e-nose), electronic tongue (e-tongue), and electronic eye (e-eye) equipped with progressive data processing algorithms, not only can accurately accelerate the consumer-based sensory quality assessment of tea, but also can define new standards for this bioactive product, to meet worldwide market demand. Using the complex data sets from electronic signals integrated with multivariate statistics can, thus, contribute to quality prediction and discrimination. The latest achievements and available solutions, to solve future problems and for easy and accurate real-time analysis of the sensory-chemical properties of tea and its products, are reviewed using bio-mimicking ESPs. These advanced sensing technologies, which measure the aroma, taste, and color profiles and input the data into mathematical classification algorithms, can discriminate different teas based on their price, geographical origins, harvest, fermentation, storage times, quality grades, and adulteration ratio. Although voltammetric and fluorescent sensor arrays are emerging for designing e-tongue systems, potentiometric electrodes are more often employed to monitor the taste profiles of tea. The use of a feature-level fusion strategy can significantly improve the efficiency and accuracy of prediction models, accompanied by the pattern recognition associations between the sensory properties and biochemical profiles of tea.

Natural Polyphenols for the Preservation of Meat and Dairy Products

Food spoilage makes foods undesirable and unacceptable for human use. The preservation of food is essential for human survival, and different techniques were initially used to limit the growth of spoiling microbes, e.g., drying, heating, salting, or fermentation. Water activity, temperature, redox potential, preservatives, and competitive microorganisms are the most important approaches used in the preservation of food products. Preservative agents are generally classified into antimicrobial, antioxidant, and anti-browning agents. On the other hand, artificial preservatives (sorbate, sulfite, or nitrite) may cause serious health hazards such as hypersensitivity, asthma, neurological damage, hyperactivity, and cancer. Thus, consumers prefer natural food preservatives to synthetic ones, as they are considered safer. Polyphenols have potential uses as biopreservatives in the food industry, because their antimicrobial and antioxidant activities can increase the storage life of food products. The antioxidant capacity of polyphenols is mainly due to the inhibition of free radical formation. Moreover, the antimicrobial activity of plants and herbs is mainly attributed to the presence of phenolic compounds. Thus, incorporation of botanical extracts rich in polyphenols in perishable foods can be considered since no pure polyphenolic compounds are authorized as food preservatives. However, individual polyphenols can be screened in this regard. In conclusion, this review highlights the use of phenolic compounds or botanical extracts rich in polyphenols as preservative agents with special reference to meat and dairy products.

Pressurized Liquid Extraction Combined with Enzymatic-Assisted Extraction to Obtain Bioactive Non-Extractable Polyphenols from Sweet Cherry (Prunus avium L.) Pomace

Sweet cherry generates large amounts of by-products within which pomace can be a source of bioactive phenolic compounds. Commonly, phenolic compounds have been obtained by conventional extraction methodologies. However, a significant fraction, called non-extractable polyphenols (NEPs), stays held in the conventional extraction residues. Therefore, in the present work, the release of NEPs from cherry pomace using pressurized liquid extraction (PLE) combined with enzyme-assisted extraction (EAE) using Promod^TM enzyme is investigated for the first time. In order to study the influence of temperature, time, and pH on the NEPs extraction, a response surface methodology was carried out. PLE-EAE extracts displayed higher TPC (75 ± 8 mg GAE/100 g sample) as well as, PA content, and antioxidant capacity than the extracts obtained by PLE (with a TPC value of 14 ± 1 mg GAE/100 g sample) under the same extraction conditions, and those obtained by conventional methods (TPC of 8.30 ± 0.05 mg GAE/100 g sample). Thus, PLE-EAE treatment was more selective and sustainable to release NEPs from sweet cherry pomace compared with PLE without EAE treatment. Besides, size-exclusion chromatography profiles showed that PLE-EAE allowed obtaining NEPs with higher molecular weight (>8000 Da) than PLE alone.