Effect of in vitro digestion and fermentation of kiwifruit pomace polysaccharides on structural characteristics and human gut microbiota.

Kiwifruit pomace is abundant in polysaccharides that exhibit diverse biological activities and prebiotic potential. This study delves into the digestive behavior and fermentation characteristics of kiwifruit pomace polysaccharides (KFP) through an in vitro simulated saliva-gastrointestinal digestion and fecal fermentation. The results reveal that following simulated digestion of KFP, its molecular weight reduced by 4.7%, and the reducing sugar (CR) increased by 9.5%. However, the monosaccharide composition and Fourier transform infrared spectroscopy characteristics showed no significant changes, suggesting that KFP remained undigested. Furthermore, even after saliva-gastrointestinal digestion, KFP retained in vitro hypolipidemic and hypoglycemic activities. Subsequently, fecal fermentation significantly altered the physicochemical properties of indigestible KFP (KFPI), particularly leading to an 89.71% reduction in CR. This indicates that gut microbiota could decompose KFPI and metabolize it into SCFAs. Moreover, after 48 h of KFPI fecal fermentation, it was observed that KFPI contributed to maintaining the balance of gut microbiota by promoting the proliferation of beneficial bacteria like Bacteroides, Lactobacillus, and Bifidobacterium, while inhibiting the unfavorable bacteria like Bilophila. In summary, this study offers a comprehensive exploration of in vitro digestion and fecal fermentation characteristics of KFP, providing valuable insights for potential development of KFP as a prebiotic for promoting intestinal health.

Effects of kiwi fruit (Actinidia chinensis) polysaccharides on metabolites and gut microbiota of acrylamide-induced mice.

Introduction: Kiwifruit (Actinidia chinensis) has rich nutritious and medicinal properties. It is widely consumed worldwide for the intervention of metabolism disorders, however, the underlying mechanism remains unclear. Acrylamide, a well-known toxic ingredient, mainly forms in high-temperature processed carbohydrate-rich food and causes disorders of gut microbiota and systemic metabolism. Methods: This study explored the protective effects and underlying mechanisms of kiwifruit polysaccharides against acrylamide-induced disorders of gut microbiota and systemic metabolism by measuring the changes of gut microbiota and serum metabolites in mice. Results: The results showed that kiwifruit polysaccharides remarkably alleviated acrylamide-induced toxicity in mice by improving their body features, histopathologic morphology of the liver, and decreased activities of liver function enzymes. Furthermore, the treatment restored the healthy gut microbiota of mice by improving the microbial diversity and abundance of beneficial bacteria such as Lactobacillus. Metabolomics analysis revealed the positive effects of kiwifruit polysaccharides mainly occurred through amino and bile acid-related metabolism pathways including nicotinate and nicotinamide metabolism, primary bile acid biosynthesis, and alanine, aspartate and glutamate metabolism. Additionally, correlation analysis indicated that Lactobacillus exhibited a highly significant correlation with critical metabolites of bile acid metabolism. Discussion: Concisely, kiwifruit polysaccharides may protect against acrylamide-induced toxicity by regulating gut microbiota and metabolism.