Impacts of different extraction methods on the structure, digestive stability, fermentation dynamics, and prebiotic properties of Zanthoxylum schinifolium Siebold & Zucc leaf polysaccharides

In this study, polysaccharides from Zanthoxylum schinifolium Siebold and Zucc. leaves (ZLPs) were obtained through five extraction methods: hot water extraction (HWE-CPS), ultrasound-assisted extraction (UAE-CPS), enzymatic extraction (EAE-CPS), microwave-assisted extraction (MAE-CPS), and microwave–enzyme co-assisted extraction (MA–EAE-CPS). Structural analysis showed that ZLPs consist mainly of galacturonic acid (30.34 mol%–34.24 mol%) and galactose (33.94 mol%–37.59 mol%), with molecular weights ( Mw ) ranging from 1648 to 3859 kDa. Ultrasound-assisted extraction reduced the Mw . All the ZLPs resisted degradation under simulated gastrointestinal conditions, with UAE–CPS exhibiting the strongest resistance and EAE–CPS the weakest. The prebiotic potentials of HWE–CPS, UAE–CPS, and MA–EAE–CPS were assessed by in vitro colonic fermentation. After 48 h, all the samples were extensively degraded, and the microbial composition (pH declined to 6.13, 5.58, and 5.50) led to a significant increase in Bacteroidetes and a decrease in Proteobacteria. Fermentation also elevated short-chain fatty acids (SCFAs) levels, with UAE-CPS yielding the highest total SCFAs concentration (42.42 mmol/L). Correlation analysis indicated that the ratio of the RG-I domain was positively correlated with the abundance of certain beneficial microorganisms and the production of SCFAs. These findings provide valuable insights into polysaccharide extraction from plant leaves and provide a reference for the application of ZLPs as functional prebiotic ingredients.