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

Antifungal mechanism and application to phytopathogenic fungi after anaerobic fermentation of Gracilaria agar wastewater

Agar production is accompanied by a large amount of wastewater, which threatens the ecological environment and wastes biomass resources. The high-value utilization of biomass resources in wastewater is one of the key factors in wastewater treatment. We investigated the conversion process and antifungal mechanism of large molecule polysaccharides in wastewater into small molecule substances with antifungal activity through anaerobic fermentation. The results indicated that anaerobic fermentation of GAW achieved inhibition rates of 91.06 % and 88.94 % against Alternaria alternata and Alternaria spp. 16S rDNA sequencing and metabolomics revealed that dominant species such as Blautia, Agathobacter and Sphingomonas converted polysaccharide into phenolic acids like procyanidin C and columbidin. These substances disrupted the integrity of fungal cells, leading to their death. The preparation of composite antifungal agents using fermentation products effectively inhibited cherry tomato spoilage and toxin production. This study provided reliable technical support for the reuse of seaweed waste resources.

Effects of acetylated polysaccharide on the prebiotic properties of grape seed proanthocyanidins - Based on in vitro fermentation with Artemisia sphaerocephala Krasch glucomannan

This study evaluated the impact of Artemisia sphaerocephala Krasch glucomannan with different degrees of acetyl group substitution (DS) on the prebiotic properties of grape seed proanthocyanidins (GSP). UV spectra, CIELab, and dynamic light scattering analyses indicated DS-influenced variable interactions between GSP and glucomannan. In vitro fermentation demonstrated that glucomannan enhanced the solubility of some phenolic compounds, and decreased the pH value of fermentation liquids. The production of acetate acid and total short chain fatty acids in the GSP fermentation liquid increased with the degree of DS of glucomannan. Notably, acetylated glucomannan exerted dramatic effects on GSP-induced gut microbiota modulation. The relative abundances of Bacteroides ovatus and Bacteroides decreased as DS increased. Meanwhile, Bacteroides acidifaciens and Akkermansia muciniphila have a positive correlation, even though the GSP-promoted enrichment of A. muciniphila was inhibited by the added glucomannan. Moreover, glucomannan enhanced the metabolism of nucleotides, secondary bile acid, and glycan inhibited by GSP. These findings suggest that acetylated glucomannan affect the prebiotic properties of GSP with its DS serving as a key factor.

In vitro digestion and fermentation of the whole goji berry: Bioactive ingredients change and impacts on human gut microbiota

Goji berry (Lycium barbarum L.) is a nutrient-rich fruit and has received enormous interest for its health benefits. The beneficial effects of goji berry are linked to the absorption of bioactive compounds within the gastrointestinal digestion process and colon fermentation. Nonetheless, how certain bioactive compounds were released, and metabolism changed of the consumption of whole goji berries were still unclear. Therefore, the present study aimed to evaluate the digestion characteristics of key bioactive compounds in whole goji berries with an in vitro digestion model, and the effects of whole goji berries on the structure of gut microbiota were also investigated. Results showed that a significant release of carbohydrates during the digestion process, peaking within the first 15 min of the intestinal phase (421.4 ± 5.82 mg GE/g, dry weight, respectively), was observed, and the phenolic release reached the highest in the first 15 min of the gastric phase. Meanwhile, the bioaccessibilities of phenolic compounds and carbohydrates were determined to be 63.87% and 80.40%, respectively, after intestinal digestion. In addition, the undigested fractions of goji berries could be further fermented to produce short-chain fatty acids, which decreased the colon pH value (from 7.38 to 6.71) as well as the Firmicutes/Bacteroidetes ratio. Moreover, the goji berries regulated the composition of gut microbiota by promoting beneficial bacteria such as Bacteroides, Parabacteroides, and Paraclostridium, whereas inhibiting the proliferation of harmful bacteria (e.g., Fusobacterium). Our results indicated that the goji berry exhibited significant bioactivity during the digestion and fermentation stage and might provide some new insights into the utilization of goji berries in healthy food processing.

In vitro digestion and colonic fermentation of phenolic compounds and their antioxidant potential in Australian beach-cast seaweeds

Beach-cast seaweed has recently garnered attention for its nutrient-rich composition, including proteins, carbohydrates, vitamins, minerals, and phytochemicals. This study focuses on the phenolic content and antioxidant potential of five Australian beach-cast seaweed species during in vitro digestion and colonic fermentation. The bioaccessibility of the selected phenolic compounds was estimated and short chain fatty acids (SCFAs) production was determined. Cystophora sp., showed a notable increase in phenolic content (23.1 mg GAE/g) and antioxidant capacity (0.42 mg CE/g) during the intestinal and gastric phases of in vitro digestion. Durvillaea sp. demonstrated a significant release of flavonoids (0.35 mg QE/g), while Phyllosphora comosa released high levels of tannins (0.72 mg CE/g) during the intestinal phase. During colonic fermentation, P. comosa released the highest levels of phenolic compounds (4.3 mg GAE/g) after 2 h, followed by an increase in flavonoids (0.15 mg QE/g), tannins (0.07 mg CE/g), and antioxidant activity (DPPH: 0.12 mg CE/g; FRAP: 0.61 mg CE/g) after 4 h. Moreover, P. comosa released a considerable amount of phenolic compounds during both in vitro digestion and colonic fermentation. All species consistently released phenolic compounds throughout the study. Phloroglucinol, gallic acid, and protocatechuic acid were identified as the most bioaccessible phenolic compounds in all five Australian beach-cast seaweeds in the in vitro digestion. Nevertheless, compound levels declined during the colonic fermentation phase due to decomposition and fermentation by gut microbiota. With regard to SCFAs, P. comosa displayed elevated levels of acetic (0.51 mmol/L) and propionic acid (0.36 mmol/L) at 2 h, while Durvillaea sp. showed increased butyric (0.42 mmol/L) and valeric (0.26 mmol/L) production acid after 8 h. These findings suggest that seaweed such as Cystophora sp., Durvillaea sp., and P. comosa are promising candidates for food fortification or nutraceutical applications, given their rich phenolic content and antioxidant properties that potentially offer gut health benefits.

Low glycemic index potato biscuits alleviate physio-histological damage and gut dysbiosis in rats with type-2 diabetes mellitus induced by high-sugar and high-fat diet and streptozotocin

Type 2 diabetes mellitus (T2DM) is the most common type of diabetes globally and poses a major concern for human health. This study aimed to investigate the effects on T2DM of low-glycemic index (GI) potato biscuits with oat bran and inulin as functional additives. T2DM was induced in rats by streptozotocin (STZ) and a high-sugar and high-fat diet. The alleviation of T2DM by low-GI potato biscuits at different doses was evaluated based on the analysis of glycolipid levels, histological observations, inflammatory markers and gut microbiota structure. Compared to wheat biscuits, low-GI potato biscuits resulted in lower postprandial blood glucose levels. After eight weeks of intervention, fasting blood sugar levels were 16.9% lower in T2DM rats fed high-dose low-GI potato biscuits than in untreated T2DM rats. Moreover, the intervention with low-GI potato biscuits significantly alleviated T2DM-induced pathological damage, glucose and lipid metabolic disorders, and inflammation by reversing the levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, transforming growth factor-β, interleukin-1β, interleukin-6 and tumor necrosis factor-α. Moreover, the levels of short-chain fatty acids and gut microbiota structure in T2DM rats were significantly reversed. The abundance of beneficial bacteria (e.g., Bifidobacterium, Lachnoclostridium, Roseburia) in the gut of T2DM rats was significantly increased whereas the abundance of Escherichia-Shigella and Desulfovibrio decreased. The present study revealed that low-GI potato biscuits alleviated damages caused by high-sugar and high-fat diet- and STZ-induced T2DM in rats, as well as reversed disturbances in the gut microbiota. Thus, low-GI potato biscuits are potentially beneficial to T2DM patients.

Multi-Index Comprehensive Assessment Optimized Critical Flavonoids Extraction from Semen Hoveniae and Their In Vitro Digestive Behavior Evaluation

Critical flavonoids from Semen Hoveniae have huge potential bioactivities on hypoglycemic. A multi-index comprehensive assessment based on Analytic Hierarchy Process (AHP) method was performed to optimize the extraction process of flavonoids from Semen Hoveniae, which taking dihydromyricetin, taxifolin, myricetin and quercetin as indexes, and, then, an in vitro simulated gastrointestinal digestion model was established to investigate the changes of flavonoids contents and their antioxidant capacity before and after digestion. The results showed that three influence factors acted significantly with the order of ethanol concentration > solid-liquid ratio > ultrasound time. The optimized extraction parameters were as follows: 1:37 w/v of solid-liquid ratio, 68% of ethanol concentration and 45 min for ultrasonic time. During in vitro digestion, the order of remaining ratio of four flavonoids in the extract was dihydromyricetin > taxifolin > myricetin > quercetin in gastric digestion, and remaining ratio of taxifolin was 34.87% while others were restructured in intestinal digestion. Furthermore, the 1,1-dipheny-2-picryhydrazyl free radical (DPPH ·) scavenging ability and oxygen radical absorption capacity (ORAC) of extract were more stable in gastric digestion. After an hour's intestinal digestion, the extract had no DPPH antioxidant capacity, but amazingly, its ORAC antioxidant capacity was retained or increased, which implied that substances were transformed and more hydrogen donors were produced. This study has carried out a preliminary discussion from the perspective of extraction and put forward a new research idea, to improve the in vivo bioavailability of the critical flavonoids from Semen Hoveniae.