In this study, the Chinese yam peel polysaccharide (CYPP) was obtained under the extraction conditions optimized by the Response Surface Methodology (RSM). Further biological properties of CYPP-1 purified from CYPP were also determined. The results indicated that the optimum extraction conditions were an extraction temperature of 90.5°C, a liquid-solid ratio of 28.0 ml/g, and an extraction time of 2.94 h, along with a yield of 8.81 ± 1.48%. CYPP-1 was identified as a kind of heteropolysaccharide mostly composed of glucose and galactose (59.4:1.0). The molecular weights were two main parts of 50.5 kDa (54.77%) and 4.4 kDa (21.02%), and the triple-helix conformation was not formed in CYPP-1. Besides, CYPP-1 showed good biological properties including in vitro antioxidant activity and immunomodulatory function on RAW264.7 cells, as well as favorable hypoglycemic effect. Overall, the high-value utilization of CYPP-1 reveals a broad application prospect in the industrial production of functional foods and pharmaceuticals. PRACTICAL APPLICATIONS: Yam peel, which is discarded in large quantities during postharvest processing, results in the production of tremendous by-products and is a great waste of resources. In this study, the yield of water-soluble polysaccharide from yam peel reached 8.81 ± 1.48%. Besides, the purified CYPP-1 exhibited excellent antioxidant activity, favorable immunomodulatory function, and hypoglycemic effect. The high productivity and bioactive effects are both great merits for Chinese yam peel polysaccharide as a promising candidate for foods and medicines industrial production.
Keywords: Chinese yam peel polysaccharide; antioxidant; extraction optimization; immunomodulation; physicochemical properties; α-glucosidase.
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