Total antioxidant capacity of new natural powdered seasonings after gastrointestinal and colonic digestion

The power of the QUENCHER method in measuring total antioxidant capacity of foods: Importance of interactions between different forms of antioxidants

Antioxidants play a crucial role in maintaining human health by counteracting oxidative stress and regulating redox balance within the body. The mixture of various antioxidant compounds in different forms (i.e., free, bound, insoluble) in food creates a redox active environment both in the human body and in the food system. Acting as both electron donors and acceptors while interacting with each other can either result in antagonism through pro-oxidative effects, or synergism through regeneration of one antioxidant by another. During the antioxidant capacity measurement, besides the individual antioxidant effects of the antioxidant components, these effects that occur because of their interaction with each other should be also considered. Classical antioxidant capacity measurement methods mostly concentrate on the fractions of foods that can be extracted with either water, alcohol, lipid, or acid/alkaline solutions. Antioxidants that cannot be extracted with any solvent are mostly ignored in these methods. On the other hand, the QUENCHER method, which allows direct measurement of antioxidant capacity foods without extraction, offers a rational solution to the limitations of traditional extraction-based methods. This approach considers the antioxidant capacity and interactions of all antioxidant forms that can be found in a food matrix, at the same time. This review provides detailed insights into the advantages of QUENCHER as a holistic approach for the accurate measurement of the antioxidant capacity of foods.

Effect of Pediococcus acidilactici and mango seed polyphenols on the fermentative profile of the indigestible fraction of yam bean

Yam bean is an important source of dietary fiber and other components that comprise the total indigestible fraction (TIF), which can be fermented by the colonic microbiota and produce metabolites with beneficial health effects. Therefore, the objective of this study was to evaluate the in vitro colonic fermentation of yam bean TIF and the changes caused by the addition of a polyphenolic extract of mango seed and the lactic acid bacteria Pediococcus acidilactici. The mango seed extract was obtained by ultrasound-assisted extraction, and the microbial growth rate and viability of P. acidilactici were determined using a Neubauer chamber. Yam bean TIF was isolated by triple enzymatic hydrolysis and subjected to in vitro colonic fermentation in combination with treatments with mango seed extract and P. acidilactici suspensions. Changes in pH, total soluble phenols (TSP), and antioxidant capacity (AOX) were evaluated. Furthermore, the production of metabolites was quantified by HPLC-DAD-MS and GC-MS. The Growth rate of P. acidilactici was 0.1097 h-1 with 97.5 % viability at 7 h of incubation. All TIF treatments showed a high capacity of fermentation, and the addition of mango seed extract increased the TSP content and AOX in DPPH and FRAP assays. A total of Forty-six volatile metabolites were detected, with highlighting the presence of esters, benzenes, aldehydes, and short-chain fatty acids. Five phenolic compounds associated with mango by-products were quantified during all fermentation process, despite the concentration of the extract. P. acidilactici did not substantially modify the fermentative profile of TIF. However, further studies such as the evaluation of the abundance of microbial communities may be necessary to observe whether it can generate changes during colonic fermentation.

Influence of the packaging systems on the phenolic profile and antioxidant properties of wine pomace used as seasoning in chicken meat

White wine pomace products (wWPP) represent an innovative strategy as a functional food ingredient to be used as a seasoning both for their technological and functional properties. Nevertheless, the bioactive compounds of wWPP used as a seasoning could be modified during storage. The seasoning in the meat, regardless of the storage method used, modified its phenolic profile and in its bioaccessible fractions, while maintaining a high total antioxidant capacity and total polyphenol content. The contact of the seasoning with the meat can be considered safe as it does not show cytotoxicity in the Caco-2 cells. Additionally, the ability to modulate the cell oxidative stress of the bioaccessible fractions and the potential benefits on microbiota by the colonic fermentation fraction, suggest its potential use as a functional ingredient, without being affected by storage. These results are novel and may help to establish the value of this product as a functional ingredient.

Antioxidant Activity of Vitis davidii Foex Seed and Its Effects on Gut Microbiota during Colonic Fermentation after In Vitro Simulated Digestion

Vitis davidii Foex whole seed (VWS) is a by-product during the processing of grape products, which is rich in bioactive compounds that have great potential in the food industry. In this study, the bioactive compounds and antioxidant activity of VWS were determined, and their dynamic changes during in vitro colonic fermentation were also investigated after VWS subjected to in vitro simulated digestion. Results showed that VWS were rich in polyphenols (23.67 ± 0.52 mg GAE/g), flavonoids (13.13 ± 1.22 mg RE/g), and proanthocyanidins (8.36 ± 0.14 mg CE/g). It also had good DPPH and ABTS radical scavenging activity, which reached 82.10% and 76.10% at 1000 μg/mL. The alteration trend of the antioxidant activity during in vitro fermentation for 24 h was consistent with that of the content of bioactive substances, such as polyphenols, with the extension of fermentation time. The bioactive compounds and antioxidant activity showed a trend of increasing and then decreasing, reaching the highest value at 8 h. The high-throughput sequencing analysis of the regulatory effect of VWS on intestinal micro-organisms revealed that VWS influenced intestinal microbiota diversity. The relative abundance of beneficial microbiota, such as Blautia and Parabacteroides, increased by 4.1- and 1.65-fold after 24 h of fermentation compared with that of the control group. It also reduced Escherichia-Shigella by 11.23% and effectively reduced host inflammation, while increasing the contents of acetic acid, propionic acid, and other metabolites. Taken together, these results reveal the value of VWS utilization and provide new insights into the nutritional and microbiota modulation effects of VWS, which could therefore serve as a nutraceutical ingredient in health promotion.

Bioactivity and Bioaccessibility of Bioactive Compounds in Gastrointestinal Digestion of Tomato Bagasse Extracts

A nutrient-rich diet is a key to improving the chemical signals, such as antioxidants, which modulate pathogens’ resistance in the gut and prevent diseases. A current industrial problem is the generation of undervalued by-products, such as tomato bagasse, which are rich in bioactive compounds and of commercial interest (carotenoids and phenolic compounds). This work analyzed the effect of gastrointestinal digestion on the bioactivity and bioaccessibility of carotenoids and phenolic compounds from tomato bagasse extracts. Thus, the extraction by ohmic heating (OH) technology was compared with conventional (organic solvents). The results showed that the main phenolic compounds identified by UPLC-qTOF-MS were p-coumaric acid, naringenin, and luteolin. A higher recovery index for total phenolic compounds throughout the gastrointestinal digestion was observed for OH while for carotenoids, a strong reduction after stomach conditions was observed for both extracts. Furthermore, colon-available fraction exhibited a prebiotic effect upon different Bifidobacterium and Lactobacillus, but a strain-dependent and more accentuated effect on OH. Thus, the extraction technology highly influenced bioaccessibility, with OH demonstrating a positive impact on the recovery of bioactive compounds and related health benefits, such as antioxidant, anti-hypertensive, prebiotic, and anti-inflammatory properties. Of these properties, the last is demonstrated here for the first time.

Effects of Grape Pomace Polyphenols and In Vitro Gastrointestinal Digestion on Antimicrobial Activity: Recovery of Bioactive Compounds

Grape pomace (GP), a major byproduct obtained from the winemaking process, is characterized by a high amount of phenolic compounds and secondary plant metabolites, with potential beneficial effects on human health. Therefore, GP is a source of bioactive compounds with antioxidant, antimicrobial, and anti-inflammatory activity. As people are paying more attention to sustainability, in this work, we evaluate two different extractions (aqueous and hydroalcoholic) of GP bioactive compounds. In vitro simulated gastrointestinal digestion of the GP extracts was performed to improve the bioavailability and bioaccessibility of polyphenols. The antioxidant activity (ABTS and DPPH assays) and the phenolic characterization of the extracts by UHPLC-DAD were evaluated. The antimicrobial effects of GP antioxidants in combination with a probiotic (Lactiplantibacillus plantarum) on the growth of pathogenic microorganisms (Escherichia coli, Bacillus megaterium, and Listeria monocytogenes) were evaluated. As a result, an increase of antioxidant activity of aqueous GP extracts during the gastrointestinal digestion, and a contextual decrease of hydroalcoholic extracts, were detected. The main compounds assessed by UHPLC-DAD were anthocyanins, phenolic acids, flavonoids, and stilbenes. Despite lower antioxidant activity, due to the presence of antimicrobial active compounds, the aqueous extracts inhibited the growth of pathogens.

Dietary Fiber in Plant Cell Walls—The Healthy Carbohydrates

Dietary fiber (DF) is one of the major classes of nutrients for humans. It is widely distributed in the edible parts of natural plants, with the cell wall being the main DF-containing structure. The DF content varies significantly in different plant species and organs, and the processing procedure can have a dramatic effect on the DF composition of plant-based foods. Given the considerable nutritional value of DF, a deeper understanding of DF in food plants, including its composition and biosynthesis, is fundamental to the establishment of a daily intake reference of DF and is also critical to molecular breeding programs for modifying DF content. In the past decades, plant cell wall biology has seen dramatic progress, and such knowledge is of great potential to be translated into DF-related food science research and may provide future research directions for improving the health benefits of food crops. In this review, to spark interdisciplinary discussions between food science researchers and plant cell wall biologists, we focus on a specific category of DF—cell wall carbohydrates. We first summarize the content and composition of carbohydrate DF in various plant-based foods, and then discuss the structure and biosynthesis mechanism of each carbohydrate DF category, in particular the respective biosynthetic enzymes. Health impacts of DF are highlighted, and finally, future directions of DF research are also briefly outlined.

Bioaccessibility and bioavailability of bioactive compounds from yellow mustard flour and milk whey fermented with lactic acid bacteria

Microbial fermentation with lactic acid bacteria (LAB) is a natural food biopreservation method. Yellow mustard and milk whey are optimum substrates for LAB fermentation. The aim of the present study was to evaluate the bioaccessibility and bioavailability of bioactive compounds from yellow mustard flour and milk whey both with and without LAB fermentation. All extracts were subjected to a simulated digestion process. Total polyphenols, DL-3-phenyllactic acid (PLA), lactic acid, and the antioxidant activity were determined in the studied matrices before and after simulated digestion. Yellow mustard flour was significantly richer in total polyphenols, whereas significantly higher concentrations of PLA and lactic acid were observed in milk whey. Similar antioxidant activity was determined in both ingredients being in all cases strongly reduced after in vitro digestion. Higher bioaccessibility was found for polyphenols and PLA in milk whey. Transepithelial transport of total polyphenols was higher in yellow mustard flour compared to milk whey, reaching bioavailability values between 3-7% and 1-2%, respectively. PLA transepithelial transport was only significant in both fermented matrices with bioavailability around 4-6%. Transepithelial transport of lactic acid reached values of 31-34% (bioavailability ∼ 22%) and 15-78% (bioavailability ∼ 3%) in milk whey and yellow mustard flour, respectively. LAB fermentation showed beneficial effects on enriching extracts with PLA, lactic acid, and antioxidant activity, as well as increasing bioaccessibility of these acids in yellow mustard flour and total polyphenol bioavailability in milk whey. Results pointed to yellow mustard flour and milk whey as natural preservative ingredients used in the food industry, especially when fermented with LAB.

From winery by-product to healthy product: bioavailability, redox signaling and oxidative stress modulation by wine pomace product

The wine pomace is the main winery by-products that suppose an economic and environmental problem and their use as a functional ingredient are being increasingly recognized as a good and inexpensive source of bioactive compounds. In this sense, it is known the potential health properties of wine pomace products in the prevention of disorders associated with oxidative stress and inflammation such as endothelial dysfunction, hypertension, hyperglycemia, diabetes, obesity. Those effects are due to the bioactive compounds of wine pomace and the mechanisms concern especially modulation of antioxidant/prooxidant activity, improvement of nitric oxide bioavailability, reduction of pro-inflammatory cytokines and modulation of antioxidant/inflammatory signal pathways. This review mainly summarizes the mechanisms of wine pomace products as modulators of oxidative status involved in cell pathologies as well as their potential therapeutic use for cardiovascular diseases. For this purpose, the review provides an overview of the findings related to the wine pomace bioactive compounds profile, their bioavailability and the action mechanisms for maintaining the redox cell balance involved in health benefits. The review suggests an important role for wine pomace product in cardiovascular diseases prevention and their regular food intake may attenuate the development and progression of comorbidities associated with cardiovascular diseases.

Dietary Fiber: Fractionation, Characterization and Potential Sources from Defatted Oilseeds

Dietary fiber (DF) has wide applications, especially in the food and pharmaceutical industries due to its health-promoting effects and potential techno-functional properties in developing functional food products. There is a growing interest in studies related to DF; nevertheless, there is less focus on the fractionation and characterization of DF. The characteristics of DF fractions explain their functionality in food products and provide clues to their physiological effects in food and pharmaceutical industrial applications. The review focuses on a brief introduction to DF and methods for its fractionation. It discusses the characterization of DF in terms of structural, physicochemical and rheological properties. The potential sources of DF from selected defatted oilseeds for future studies are highlighted.

Quality of New Functional Powdered Beverages Enriched with Lyophilized Fruits—Potentially Bioaccessible Antioxidant Properties, Nutritional Value, and Consumer Analysis

This study evaluates nutrients and health-promoting compounds responsible for antioxidant capacity in eight novel formulations based on lyophilized fruit and vegetable powders. The composition contained lyophilized carrot, pumpkin, lentil sprouts, raspberry, strawberry, and apple. The effect of functional additives on the antioxidant, nutritional, and functional characteristics of powdered beverages was determined in the powders and after rehydration followed by in vitro digestion. The antioxidant activity, phenols, vitamin C, and reducing power were significantly higher in the powders enriched with additives having potential functional properties. Furthermore, the analyses indicated that all the powdered formulations may be potential sources of total starch (100–112 mg/100 mL) and proteins (125–139 mg/100 mL). The designed powdered beverages after reconstitution exhibited high antioxidant content, reasonable consumer acceptance, and good in vitro bioaccessibility. The best results of antioxidant capacity were obtained for beverages enriched with raspberry, i.e., 10.4 mg Trolox equivalent (TE)/100 mL and 12.1 mg TE/100 mL rehydrated at 20 °C and 80 °C, respectively. Additionally, color characteristics were used as indicators of the quality of the powdered beverages. This research promotes the reduction of food waste, since whole plant tissues are used, thus allowing maximum exploitation of food raw materials; moreover, drying provides stable shelf life.

Functional Components, Antioxidant Activity and Hypoglycemic Ability Following Simulated Gastro-Intestinal Digestion of Pigments from Walnut Brown Shell and Green Husk

To assess the effects of digestion on the functional components of walnut pigment and their bioactivities, we developed an in vitro model simulating gastro-intestinal digestion. Results showed an increase in the contents of flavonoids and conjugated phenols (with retention rates higher than 100%) in husk pigment after digestion. The lowest of the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging abilities was reached in the group with the minimum flavonoid content after digestion. Close correlation was observed between free phenol content and total reducing power, as the reducing power among different groups of husk pigment was in consistent with free phenols changes. The inhibitory effect of walnut pigment on α-amylase with/without digestion enzyme was similar. However, shell pigment showed improved inhibitory effect on α-glucosidase activity, with an increased inhibitory rate of 5.42%. In general, the antioxidant activity and hypoglycemic ability of walnut pigment were prone to chemical and enzymatic changes during simulated digestion, which were also related to the alteration of flavonoids and phenols.

Wu Shan Shen Cha (Malus asiatica Nakai. Leaves)-Derived Flavonoids Alleviate Alcohol-Induced Gastric Injury in Mice via an Anti-Oxidative Mechanism

Wu Shan Shen Cha is the leaf of Malus asiatica Nakai., a special type of tea that is consumed in the same way as green tea. To study the effect of Wu Shan Shen Cha-derived flavonoids (WSSCF) on lesions in the stomach, a 15% hydrochloric acid–95% ethanol (volume ratio 4:6) solution was used to induce gastric injury in mice. The degree of gastric injury was assessed using tissue specimens, and the effects of WSSCF on the serum levels of antioxidant enzymes were investigated. The results showed that WSSCF could alleviate the damage of the gastric mucosa and gastric wall caused by the hydrochloric acid–ethanol solution, decrease the tissue and serum levels of malondialdehyde (MDA) in mice with gastric injury, and increase the serum levels of superoxide dismutase (SOD) and glutathione (GSH). The results of quantitative polymerase chain reaction (qPCR) showed that WSSCF could increase the mRNA expression of Mn-SOD, Cu/Zn-SOD, catalase (CAT), endothelial nitric oxide synthase (eNOS), and neuronal nitric oxide synthase (nNOS) in tissue specimens from mice with gastric injury and decrease the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). At the same time, the results of the high concentration of WSSCF (WSSCFH) group were closer to those of the drug (ranitidine) treatment group. Wu Shan Shen Cha-derived flavonoids had a good antioxidant effect, so as to play a preventive role in alcoholic gastric injury.

Polyphenol bioavailability in nuts and seeds by an in vitro dialyzability approach

An in vitro dialyzability approach has been undertaken to elucidate the bioavailable fraction of the total polyphenols (TPs) of edible nuts and seeds. The TP contents in samples and in dialyzates were assessed by the Folin-Ciocalteu spectrophotometric method. Antioxidant activity was determined in selected samples, using a modified method against Trolox®. TPs and antioxidant activity in nuts/seeds were determined after applying a pressurized liquid extraction sample pre-treatment. High dialyzability ratios were assessed in most nuts/seeds (TP dialyzability percentages within the 25-91% range). The highest TP dialyzability ratios were found in raw Brazil nuts (81 ± 5%), toasted pistachios (88 ± 9%), and fried cashews (89 ± 9%), whereas TPs in pumpkin seeds were found to be very low (TPs were not detected in the dialyzable fraction). TP dialyzability was correlated with the copper content in nuts and seeds.

In vitro human colonic fermentation of indigestible fraction isolated from lunch menus: impact on the gut metabolites and antioxidant capacity

The indigestible fraction (IF) isolated from three lunch menus: Modified Mexican Lunch (MM-L), Traditional Mexican Lunch (TM-L) and Alternative Mexican Lunch (AM-L), was studied in terms of antioxidant capacity (AOX) and metabolites produced through fermentation by human intestinal microbiota. IFs were isolated after withstanding in vitro gastrointestinal digestion and total soluble polyphenols (TSP), condensed tannins (CT), hydrolysable polyphenols (HP) and AOX (DPPH, FRAP) were evaluated. AOX, pH and bacterial metabolites profile changes were also monitored during in vitro colonic fermentation. Lunch menus showed differences in IF, TSP, CT and FRAP values (p<.05). TM-L had the highest TSP and CT contents (0.84 and 1.89 g/100 g DW, respectively). Changes in pH and AOX during fermentation were time-dependent and substrate-dependent (p<.05). Butyric acid production was not significantly modified by the IFs (p>.05). Fifty-seven microbiota-produced volatile compounds were detected by SPME-GC-MS. This study shows the potential effects of food habits on bacterial metabolite production.

Modified Sample Preparation Approach for the Determination of the Phenolic and Humic-Like Substances in Natural Organic Materials By the Folin Ciocalteu Method

A novel modification of the sample preparation procedure for the Folin-Ciocalteu colorimetric assay for the determination of total phenolic compounds in natural solid and semisolid organic materials (e.g., foods, organic solid waste, soils, plant tissues, agricultural residues, manure) is proposed. In this method, the sample is prepared by adding sodium sulfate as a solid diluting agent before homogenization. The method allows for the determination of total phenols (TP) in samples with high solids contents, and it provides good accuracy and reproducibility. Additionally, this method permits analyses of significant amounts of sample, which reduces problems related to heterogeneity. We applied this method to phenols-rich lignocellulosic and humic-like solids and semisolid samples, including rice straw (RS), peat-rich soil (PS), and food waste (FW). The TP concentrations measured with the solid dilution (SD) preparation were substantially higher (increases of 41.4%, 15.5%, and 59.4% in RS, PS and FW, respectively) than those obtained with the traditional method (solids suspended in water). These results showed that the traditional method underestimates the phenolic contents in the studied solids.

Effect of in vitro simulated gastrointestinal digestion on polyphenol and polysaccharide content and their biological activities among 22 fruit juices

Polyphenols and polysaccharides, as natural bioactive compounds from common fresh fruits, are concerned in reducing risk of developing obesity and diabetes for human in recent years. The content of polyphenol and polysaccharide, their bioactivities among 22 fruit juices were investigated before and after in vitro gastrointestinal digestion in present study. After digestion, contents of polyphenol, polysaccharide and their antioxidant activity, the inhibitory activity of α-amylase and α-glucosidase significantly increased. Punica granatum Linn and Actinidia globosa C. F. Liang displayed maximal increment up to 2, 0.25 and 1.6 fold in contents of polyphenols and polysaccharides, and the inhibitory activity of α-amylase, respectively. The correlation coefficient between contents and inhibitory activity of α-amylase increased in range of 0.002 to 0.485. Lycopersicon esculentum Mill and Pyrus bretschneideri Rehd exhibited maximum increase in the inhibitory activity of α-glucosidase with lowest contents of polyphenols and polysaccharides. The results indicated that polyphenols and polysaccharides digested synergistically contributing to the inhibitory α-amylase activity, and other responsibly bioactive ingredients for inhibitory α-glucosidase activity would be worthy discussed future. The findings above highlighted some potential application of common fruit juices in controlling hyperglycemia and obesity.

Electrochemical reverse engineering: A systems-level tool to probe the redox-based molecular communication of biology

The intestine is the site of digestion and forms a critical interface between the host and the outside world. This interface is composed of host epithelium and a complex microbiota which is "connected" through an extensive web of chemical and biological interactions that determine the balance between health and disease for the host. This biology and the associated chemical dialogues occur within a context of a steep oxygen gradient that provides the driving force for a variety of reduction and oxidation (redox) reactions. While some redox couples (e.g., catecholics) can spontaneously exchange electrons, many others are kinetically "insulated" (e.g., biothiols) allowing the biology to set and control their redox states far from equilibrium. It is well known that within cells, such non-equilibrated redox couples are poised to transfer electrons to perform reactions essential to immune defense (e.g., transfer from NADH to O₂ for reactive oxygen species, ROS, generation) and protection from such oxidative stresses (e.g., glutathione-based reduction of ROS). More recently, it has been recognized that some of these redox-active species (e.g., H₂O₂) cross membranes and diffuse into the extracellular environment including lumen to transmit redox information that is received by atomically-specific receptors (e.g., cysteine-based sulfur switches) that regulate biological functions. Thus, redox has emerged as an important modality in the chemical signaling that occurs in the intestine and there have been emerging efforts to develop the experimental tools needed to probe this modality. We suggest that electrochemistry provides a unique tool to experimentally probe redox interactions at a systems level. Importantly, electrochemistry offers the potential to enlist the extensive theories established in signal processing in an effort to "reverse engineer" the molecular communication occurring in this complex biological system. Here, we review our efforts to develop this electrochemical tool for in vitro redox-probing.

Chemopreventive Potential of Powdered Red Wine Pomace Seasonings against Colorectal Cancer in HT-29 Cells

This study evaluates the antiproliferative and antigenotoxic actions of powdered red wine pomace seasonings (Sk-S, seedless; W-S, whole; Sd-S, seeds). In vitro gastrointestinal digested and colonic fermented fractions of the seasonings were used as cell treatments. Phenolic acids from Sk-S showed the highest bioaccessibility in the small intestine, whereas polyphenols contained in Sd-S might be the most fermentable in the colon. Dietary fiber from Sk-S was the best substrate for short chain fatty acids production by gut microbiota. Colon cancerous (HT-29) cell viability was inhibited by 50% (IC₅₀ values) at treatment concentrations ranging from 845 (Sk-S) to 1085 (Sd-S) μg/mL prior digestion, but all digested fractions exhibited similar antiproliferative activities (mean IC₅₀ = 814 μg/mL). Oxidative DNA damage in cells was also attenuated by the treatments (200 μg/mL, 24 h preincubation), with all colonic fermented fractions displaying similar genoprotective action. These results suggest the potential of red wine pomace seasonings as chemopreventive agents in colorectal cancer.