关键词: 葡萄皮渣；游离酚；酯化酚；结合酚；营养成分；功能活性

Abstract: In this study, the nutrient, amino acid and anthocyanin composition of three varieties (Rose Honey, Cloud Dance, and French Wild) of wine grape pomace from Yunnan were investigated. Subsequently, the in vitro antioxidant and hypoglycemic activities of the free, esterified and bound phenols extracted from each variety of wine grape pomace were evaluated in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging activities, ferric reducing power, α-glucosidase and α-amylase inhibitory activities. Meanwhile, qualitative analysis of phenolic compounds was conducted using high performance liquid chromatography (HPLC). The results showed that the three varieties of grape pomace had similar nutrient composition, characterized by high dietary fiber content, low fat content, and abundant content and reasonable composition of essential amino acids. Overall, Rose Honey had the highest nutritional value. Furthermore, two types of anthocyanidins and 34 types of anthocyanins, primarily in the form of 3-O-glucoside, were identified in all the samples. Notably, Cloud Dance showed the highest number and amount of anthocyanidins, followed by Rose Honey. Additionally, among the three varieties of grape pomace, Rose Honey exhibited the highest total phenol content and the strongest antioxidant capacity and α-glucosidase inhibitory activity, but its α-amylase inhibitory activity was similar to that of French Wild. Regarding the different forms of phenols, the total content and in vitro antioxidant capacity of bound phenols were higher than those of free and esterified phenols, whereas the esterified phenols demonstrated higher α-amylase inhibitory activity. A total of 18 phenolic compounds were detected in the three varieties of grape pomace, with Rose Honey being found to contain a larger number of phenolic compounds (16) than the other two varieties. Moreover, the content of bound phenols was higher than those of free and esterified phenols. In conclusion, these three varieties of grape pomace possess good nutritional value and functional activities, which are suitable to be developed as functional food ingredients due to their high dietary fiber content and low fat content as well as antioxidant and hypoglycemic activity. Among these three varieties, Rose Honey has the greatest development potential. The findings of this study provide important reference for the high-value comprehensive utilization of Yunnan wine grape pomace and even for the development of the highland grape wine industry in Yunnan.

Key words: grape pomace; free phenols; esterified phenols; bound phenols; nutritional composition; functional activity