Impacts of processing conditions on digestive recovery of polyphenolic compounds and stability of the antioxidant activity of green tea infusion during in vitro gastrointestinal digestion

Antioxidant capacities and non-volatile metabolites changes after solid-state fermentation of soybean using oyster mushroom (Pleurotus ostreatus) mycelium

Given the abundance of beneficial properties and enzymes secreted by edible oyster mushrooms, their mycelium could serve as a starter for fermented foods to enhance their nutritional and bioactive quality. This study aimed to investigate the effects on the nutritional ingredients, antioxidant activity, and non-volatile metabolites during solid-state fermentation (SSF) of soybeans by Pleurotus ostreatus mycelium. The results indicated that the contents of dietary fiber and starch in fermented soybeans decreased, while the amounts of protein and lipid increased after SSF (P < 0.05). Analysis of the total phenolic content (TPC) and antioxidant activities of the fermented soybeans revealed that the methanolic extracts significantly increased TPC and antioxidant activities against intracellular reactive oxygen species (ROS) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, as well as against DPPH and ABTS radicals in vitro. A total 154 differential metabolites were identified after SSF, and a Spearman correlation study revealed a direct relationship between antioxidant activities and certain metabolites including phenolic compounds, oligopeptides, and free fatty acids etc. Among these metabolites, phenolic compounds produced by the shikimic acid pathway were diverse in variety and had the greatest multiple differences. The study discovered that a potential mechanism involving SSF with P. ostreatus mycelium increased the antioxidant activity of soybeans.

Synergistic effects of superfine grinding and high hydrostatic pressure on the contents, distribution, digestive behaviors and antioxidant activities of polyphenols in barley leaves

Barley leaves (BLs) naturally contained abundant phenolics, most of which are hardly completely released from food matrix during gastrointestinal digestion. Superfine grinding (SFG) and high hydrostatic pressure (HHP) are generally used to treat the functional plants due to their effectiveness to cell wall-breaking and improvement of nutraceutical bioavailability. Thus, this study investigated the synergistic effects of SFG and HHP (100, 300, 500 MPa/20 min) on the bioaccessbility of typical phenolics in BLs during the simulated in-vitro digestion. The results demonstrated that the highest bioaccessbility (40.98%) was found in the ultrafine sample with HHP at 500 MPa. CLSM and SEM confirmed SFG led to microstructurally rapture of BLs. Moreover, the recovery index of ABTS radical scavenging activity and FRAP of HHP-treated ultrafine and fine BLs samples maximumly increased by 53.62% and 9.61%, respectively. This study is expecting to provide the theoretical basis to improve the consumer acceptance of BLs.

Flavor Characteristics, Antioxidant Activity and In Vitro Digestion Properties of Bread with Large-Leaf Yellow Tea Powder

Foods containing tea could be widely utilized due to the addition of good tea ingredients, especially large-leaf yellow tea, which is rich with a good flavor. Applying this change to bread containing tea would improve its product quality. In this research, large-leaf yellow tea bread (LYB), possessing a special flavor, was developed using ultrafine large-leaf yellow tea powder and flour as the main raw materials. The amount of ultrafine large-leaf yellow tea powder added to bread was optimized using texture, sensation, and specific volume as comprehensive evaluation indicators. At the optimal dosage, the free amino acids, volatile flavor compounds, antioxidant activity, and in vitro starch digestibility of LYB were measured. Response surface optimization experimental results showed that the comprehensive score of bread was highest when the added amount of ultrafine large-leaf yellow tea powder was 3%. In particular, compared to blank bread (BB), adding ultrafine large-leaf yellow tea powder into bread could effectively increase its amino acid composition, enhance its volatile flavor compounds, improve the antioxidant capacity, and reduce the digestibility of starch.

Wild and Micropropagated Artemisia eriantha Infusions: In Vitro Digestion Effects on Phenolic Pattern and Antioxidant Activity

This study investigated the in vitro simulated gastrointestinal digestion (GID) effects on wild and micropropagated Apennines Genepì infusions. Wild and micropropagated infusions were compared for their antioxidant activity, phenolic contents, and polyphenolic profiles before and after GID. Before digestion, the wild infusions had higher amounts of phenolic compounds and antioxidant activity than the micropropagated ones. Instead, after digestion, the differences in the total phenolic content (TPC) and antioxidant activity between wild and micropropagated infusions were less pronounced. The changes in the TPC and phenolic profiles revealed the presence of several chemical transformations and rearrangements that resulted in compounds with different reactivity and antioxidant potential. Without enzyme actions, the wild infusion digest undergoes higher modifications than those obtained from the micropropagated ones. The current study offers the first concrete proof of the impact of GID on the polyphenolic chemicals present in infusions of wild and micropropagated Apennines Genepì and their antioxidant properties. Our findings are essential for future in-depth analyses of Apennine Genepì infusions and their potential impacts on human health.

Effects of processing methods on quality, antioxidant capacity, and cytotoxicity of Ginkgo biloba leaf tea product

BACKGROUND

Ginkgo biloba leaves contain beneficial flavonoids, bilobalide (BB), and ginkgolides. However, the toxic ginkgolic acid (GA) limit its application. In this study, various traditional processing methods were used to prepare G. biloba leaf tea (GBLT), including white tea, black tea, dark tea, green tea, and freeze-dried as control, followed by investigations of their effects on quality, antioxidant capacity, bioactive components, and cytotoxicity of the tea products.

RESULTS

Results showed that different processing methods significantly impact the tea products' quality indexes and the principal component analysis (PCA) and hierarchical cluster analysis (HCA) corroborated it. White tea had the highest total sugar (TS) and GA content and the most potent cytotoxicity on HepG2 cells. However, TS and GA content and the cytotoxicity of GBLT markedly decreased during fermentation and fixation. Moreover, white tea possessed higher total phenolic content (TPC), total flavonoid content (TFC), and more vigorous antioxidant activities than green tea, black tea, and dark tea. Terpene trilactones value was stable, but different catechins contents fluctuated according to the manufacturing process of different GBLTs. Among the four GBLTs, dark tea combining fixation and fermentation had the lowest GA content and cytotoxicity, less bioactive components reduction, appropriate quality, and stronger flavor.

CONCLUSION

These findings demonstrate that fixation and fermentation help reduce GAs during the manufacturing of GBLT. However, their ability to retain bioactive substances needs further optimization in future studies. © 2023 Society of Chemical Industry.

Effects of Adding Blueberry Residue Powder and Extrusion Processing on Nutritional Components, Antioxidant Activity and Volatile Organic Compounds of Indica Rice Flour

Using indica rice flour as the main raw material and adding blueberry residue powder, the indica rice expanded powder (REP) containing blueberry residue was prepared by extrusion and comminution. The effects of extrusion processing on the nutritional components, color difference, antioxidant performance and volatile organic compounds (VOCs) of indica rice expanded powder with or without blueberry residue were compared. The results showed that the contents of fat and total starch decreased significantly after extrusion, while the contents of total dietary fiber increased relatively. Especially, the effect of DPPH and ABTS+ free radical scavenging of the indica rice expanded flour was significantly improved by adding blueberry residue powder. A total of 104 volatile compounds were detected in the indica rice expanded powder with blueberry residue (REPBR) by Electronic Nose and GC-IMS analysis. Meanwhile, 86 volatile organic compounds were successfully identified. In addition, the contents of 16 aldehydes, 17 esters, 10 ketones and 8 alcohols increased significantly. Therefore, adding blueberry residue powder to indica rice flour for extrusion is an efficient and innovative processing method, which can significantly improve its nutritional value, antioxidant performance and flavor substances.

Influence of Green Tea Added to Cherry Wine on Phenolic Content, Antioxidant Activity and Alpha-Glucosidase Inhibition during an In Vitro Gastrointestinal Digestion

Cherries are a good source of bioactive compounds, with high antioxidant activity as well as nutritional and therapeutic importance. In this study, cherry wines enriched with green tea infusion (mild and concentrated) were produced, and their biological properties were evaluated. During winemaking, the main vinification parameters (alcohol, reducing sugars, acidity, total polyphenol content) as well biological activity (antioxidant activity, alpha-glucosidase inhibition potential) were determined. An in vitro digestion process was also performed to evaluate the impact of the gastrointestinal environment on the biological stability of the wines, and to analyze the interactions of wine-intestinal microflora. The addition of green tea to the cherry wine significantly increased the total polyphenol content (up to 2.73 g GAE/L) and antioxidant activity (up to 22.07 mM TE/L), compared with the control wine. However, after in vitro digestion, a reduction in total polyphenols (53–64%) and antioxidant activity (38–45%) were noted. Wines fortified with green tea expressed a stronger inhibition effect on intestinal microflora growth, of which E. coli were the most sensitive microorganisms. The tea-derived bioactive compounds significantly increased the potential of alpha-glucosidase inhibition. The proposed wines could be a good alternative type of wine, with an increased polyphenol content and the potential to control the insulin response supporting therapy for diabetes.

Evaluation of the Brewing Characteristics, Digestion Profiles, and Neuroprotective Effects of Two Typical Se-Enriched Green Teas

As a functional beverage, selenium (Se)-enriched green tea (Se-GT) has gained increasing popularity for its superior properties in promoting health. In this study, we compared the brewing characteristics, in vitro digestion profiles, and protective effects on neurotoxicity induced through the amyloid-beta (Aβ) peptide of two typical Se-GTs (Enshi Yulu (ESYL) and Ziyang Maojian (ZYMJ), representing the typical low-Se green tea and high-Se green tea, respectively). ESYL and ZYMJ showed similar chemical component leaching properties with the different brewing methods, and the optimized brewing conditions were 5 min, 90 °C, 50 mL/g, and first brewing. The antioxidant activities of the tea infusions had the strongest positive correlation with the tea polyphenols among all of the leaching substances. The tea infusions of ESYL and ZYMJ showed similar digestive behaviors, and the tea polyphenols in the tea infusions were almost totally degraded or transferred after 150 min of dynamic digestion. Studies conducted in a cell model of Alzheimer’s disease (AD) showed that the extract from the high-Se green tea was more effective for neuroprotection compared with the low-Se green tea. Overall, our results revealed the best brewing conditions and digestion behaviors of Se-GT and the great potential of Se-GT or Se-enriched green extract (Se-GTE) to be used as promising AD-preventive beverages or food ingredients.

Changes in bioactive compounds and antioxidant activity of plant-based foods by gastrointestinal digestion: a review

Phenolic compounds, omnipresent in plants, are a crucial part of the human diet and are of considerable interest due to their antioxidant properties and other potential beneficial health effects, for instance, antidiabetic, antihypertensive, anti-inflammatory, and anticancer properties. The consumption of a variety of plant-based foods containing various phenolic compounds has increased due to published scientific verification of several health benefits. The release of phenolic compounds and change in their bioactivities examined through in vitro simulated gastrointestinal digestion could provide information on the biological potency of bioactive components, which will allow us to elucidate their metabolic pathways and bioactivities at target sites. This review reports on the recent research results focused on changes during the gastro and/or intestinal phase. The effect of digestive enzymes and digestive pH conditions during simulated digestion accounted for the variations in bioaccessibility and bioavailability of phenolic antioxidants as well as the corresponding antioxidant activities were also summarized and presented in the review.

Effect of Cooking on Protein Digestion and Antioxidant Activity of Different Legume Pastes

Legumes are protein-rich foods that can be used to prepare pastes or pureed foods suitable for babies and the elderly. The aims of this study were the characterization of different legume pastes (from soybean, lentil, and pea) subjected to three processing methods (ordinary cooking, pressure cooking, and microwave) and the evaluation of protein digestion and antioxidant activity during simulated gastrointestinal digestion (GID). The different cooking methods of legumes led to differences in the physicochemical properties of the pastes, as well as on the textural and viscoelastic characteristics, except for soybean samples, despite all the pastes presenting elastic properties and weak gel behavior. Cooking followed by GID improved the protein digestibility and antioxidant activity of the legumes, which was attributed to released peptides and amino acids more than free phenolics. However, the fate and extent at each digestion stage was different according to the legume type and cooking method, as it would be influenced by the matrix structure and interaction between components. This work has expanded knowledge about the properties, digestibility, and antioxidant activity of different cooked legumes for a future design of pastes.

In vitro gastrointestinal digestion of crisphead lettuce: Changes in bioactive compounds and antioxidant potential

In this study, the potential health benefits of crisphead lettuce (Lactuca sativa L.) before and after digestion were represented by the recovery, bioaccessibility, and change of bioactive compounds including total phenolic (TPC) and total flavonoids content (TFC), and bioactivities [in vitro antioxidant activities including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, ferric reducing antioxidant power (FRAP) and metal ion chelating activity (MIC)]. The release of bioactive compounds as well as bioactivities increased during gastric and intestinal digestion for 1 h and subsequently decreased when digestion was completed. The bioaccessibility of TPC and TFC at after digestion was 56-73 and 75-79%, respectively. Among all bioactivities, crisphead lettuce showed a residual activity of ABTS (61-95%) followed by FRAP (70-86%), DPPH (24-52%) and MIC (32-73%) during the digestion. Our study suggested that crisphead lettuce maintains stability in both bioactive compounds and bioactivities during the digestion.

Assessment of chemical, biological and immunological properties of "Damiana de California" Turnera diffusa Willd extracts in Longfin yellowtail (Seriola rivoliana) leukocytes

In Mexican herbal medicines or natural remedies, Turnera diffusa (Turneraceae) known as "Damiana de California", has ethnopharmacological relevance, including aphrodisiac, diuretic, and antimicrobial activities. To explore the immunological effect of infusion and methanolic extracts from Damiana de California, this study investigated its chemical, biological, antimicrobial and immunological properties in Longfin yellowtail Seriola rivoliana leukocytes. The analysis of chemical compounds revealed a considerable level of total phenolic and flavonoid contents in the infusion compared with methanolic extract. Furthermore, the antioxidant activity showed high hydroxyl radical scavenging activity in infusion extract compared with BHT positive control. Superoxide radical scavenging activity and ion chelation were higher in methanolic extract followed by infusion treatment. Interestingly, notable antimicrobial activity was observed in both extracts of T. diffusa against Vibrio parahaemolyticus. An in vitro study was performed using leukocytes of S. rivoliana treated with infusion or methanolic extracts at 12.5, 25 and 50 μg/mL for 24 h. Remarkably, infusion extract induced proliferation at any concentration but not the methanolic extract, which was diminished in a dose-dependent fashion. The immunostimulation study demonstrated that the phagocytosis activity increased in those leukocytes stimulated with methanolic extract but diminished the respiratory burst activity, in contrast to the activity observed in those leukocytes stimulated with infusion treatment. Finally, leukocytes incubated with the extracts and confronted with V.parahaemolyticus up-regulated the transcription of proinflammatory cytokine IL-1β gene in a dose response relationship. These findings suggest that the infusion treatment has potential therapeutic properties, promoting the antioxidant capacity and enhancing immune parameters in Longfin yellowtail S. rivoliana.

Effects of green tea leaf, lotus leaf, and kimchi powders on quality characteristics of chicken liver sausages

Liver sausage is flavorful and highly nutritious. However, liver has a relatively short shelf life due to acceleration of oxidation in the presence of endogenous enzymes and metals. Powders derived from natural sources, including plants or fruits, are applied to meat products for inhibiting oxidation without adverse effects on their quality. Hence, this study investigated the effects of natural powders derived from green tea leaf (GTL), lotus leaf (LL), and kimchi (KC) on the quality and change in lipid oxidation and freshness of chicken liver sausages during two weeks of storage. Chicken liver sausages were manufactured with chicken breast (70%) and liver (20%), pork back fat (5%), iced water (5%), various additives, and GTL, LL, and KC [0 (control) or 1%]. They were processed in three batches. For determination of the quality characteristics of chicken liver sausages with various plant powders, pH, color, and texture properties were assessed. In addition, lipid oxidation and freshness using thiobarbituric acid reactive substances (TBARS) and total volatile basic nitrogen (TVBN) were analyzed at day 0 and week 2 of refrigerated storage. Higher values were obtained for pH and cooking yield in sausage samples with LL and KC powders than in samples with the other treatments. For a* values, the sausage samples with KC showed similar (p > 0.05) values, whilst others had significantly lower values than the control. The addition of the three powders to sausage samples induced an increase (p < 0.05) in hardness, gumminess, and chewiness. The addition of plant powders did not influence TBARS and TVBN of sausage samples at the initial stage. However, after two weeks of storage, significantly lower TBARS and TVBN values were observed, and the sausage with KC (p < 0.05) showed the lowest values of both TBARS and TVBN. The results showed the potential ability of the three powders to improve the quality and inhibit lipid oxidation in liver sausages. Particularly, the addition of KC did not adversely affect the a* values of sausage samples. The effects on sensory properties and inhibition mechanisms of GTL, LL, and KC in meat products should be further studied.