Stuctural and in vitro Fecal Fermentation Characteristics of Oligosaccharides Produced from Chinese Quince Seed Gum by H2O2

• Chinese quince seed gum is sustainable resource of oligosaccharides (OCGs) • OCGs are potentially strong water-absorbing, semi-solid food ingredients • The antioxidant and in vitro fermentation properties of OCGs were evaluated • OCGs showed strong antioxidant properties and prebiotic potential Oligosaccharides (OCGs) are valued as prebiotics for their health benefits such as regulating lipid metabolism, enhancing mineral absorption, and promoting gut health. Chinese quince seed gum (CQSG), a polysaccharide from Chinese quince fruit by-products, is a promising source for producing functional OCGs. OCGs were prepared from CQSG using hydrogen peroxide (H₂O₂) hydrolysis. The optimal conditions for OCG production were determined to be 0.3 M H₂O₂, 120°C, and a reaction time of 2 hours, yielding 17.6% of OCGs. OCGs are a typical highly water absorbent, semisolid oligosaccharide mixture, composed mainly of arabinose and xylose, with average molecular weight of 1774 Da. The DPPH· ( 88.3%), OH· (94.7%), ABTS + · ( 86.1%) and DMPD + · (82.5%) scavenging activity results indicate that OCGs have potent antioxidant activity. During in vitro fecal fermentation, OCGs modulated the composition and diversity of gut microorganisms, increasing the abundance of Actinobacteriota and Bifidobacteria, and decreasing the abundance of Bacteroidota. These population shifts led to an increase in the concentration of short-chain fatty acids, with acetic acid and n-butyric acid being the predominant metabolites. This study surmounts the limitations of analogous functional foods by virtue of its high yield, pronounced antioxidant and prebiotic attributes, and eco-friendly processes, thereby rendering CQSG-derived OCGs an exceedingly promising candidate for functional food ingredients.