关键词: 酰基化, 花色苷, 矢车菊素-3-O-葡萄糖苷, 肉桂酸甲酯, 脂肪酶

Abstract: Anthocyanins are the most widespread natural pigments in plants, with excellent antioxidant properties, but the poor stability and low bioavailability limit their applications. Acylation modification is beneficial to improve the stability and bioavailability of anthocyanins. The present study employed methyl cinnamate of food-grade to react with centainin-3-O-glucoside (C3G) by the decompression enzyme method, which has the advantages of green safety, high efficiency and single acylation product. Then the acylated products were separated and their thermal stability and antioxidant properties were determined. The results showed that conversion rate for the acylation was 80%. The semi-preparative HPLC was used to separate and purify the acylation product, and the purity of acylated product reached 98.3%. By MS analysis, the acylation product was found to be centathrin-3 - (6-cinnamyl) -glucoside (C3(6C)G). The lipid solubility and thermal stability of anthocyanins were improved by acylation. The free radical scavenging abilities of C3G, C3(6C)G and vitamin C were determined by DPPH, ABTS, FRAP and hydroxyl radical antioxidant experiments in vitro. Compared with vitamin C at the same concentration, C3G and C3(6C)G performed well in the other three antioxidant tests except for ABTS free radical scavenging test. Compared with C3G, the hydroxyl radical scavenging ability of the acylated product C3(6C)G was significantly enhanced (P < 0.05), and there was no significant difference in antioxidant ability in DPPH, ABTS and FRAP experiments (P > 0.05), suggesting that the antioxidant ability of anthocyanins was not sacrificed after modification with cinnamyl, but the reduction ability of hydroxyl radical was significantly improved.