橙皮果胶多糖的绿色提取、理化性质及生物活性分析

To effectively utilize discarded orange peel as a resource and enhance the value of fruit products, we extracted pectin from orange peel using eco-friendly citric acid-sodium citrate buffer solutions at different pH values, then analyzed the physicochemical properties and biological activities of the extracted pectin. Pectin yield ranged from 13.1% to 36.3%, with an average galacturonic acid content of 75.81% and an average esterification degree of 26.67%. Orange peel pectin exhibited good antioxidant and bile acid binding capacity, with scavenging capacity of 95.14% for·OH, 49.62% for DPPH·, and 38.39% for ABTS⁺· at a concentration of 10 mg/mL. High-molecular-weight pectin demonstrated elevated bile acid binding ability. A Ca²⁺ binding assay revealed that pectin extracted at pH 12 exhibited optimal gel-forming ability. Rheological analysis indicated that the formed gel was predominantly elastic, with storage modulus (G′) higher than loss modulus (G″) across all samples at 0 to 250 rad/s. Finally, a probiotic viability assay using Clostridium butyricum demonstrated that the extracted pectin can promote intestinal probiotic growth and has good acidification capacity. Overall, the pectin obtained by this extraction method can directly be used as low-ester pectin, and exhibits significant biological activity. Orange peel pectin thus offers potential applications that enhance the value of fruit products and promote nutritional health.