Enzymatic Acylation of Anthocyanin Isolated from Black Rice with Methyl Aromatic Acid Ester as Donor: Stability of the Acylated Derivatives

摘要

The enzymatic acylation of anthocyanin from black rice with aromatic acid methyl esters as acyl donors and Candida antarctica lipase B was carried out under reduced pressure. The highest conversion of 91% was obtained with benzoic acid methyl ester as acyl donor; cyanidin 3-(6"-benzoy1)-glucoside, cyanidin 3-(6"-salicyloyl)-glucoside, and cyanidin 3-(6"-cinnamoyl)-glucoside were successfully synthesized. This is the first report on the enzymatic acylation of anthocyanin from black rice with methyl aromatic esters as acyl donors and lipase as biocatalyst. Furthermore, the acylation with aromatic carboxylic acids enhanced both the thermostability and light resistivity of anthocyanin. In particular, cyanidin 3-(6"-cinnamoyl)-glucoside was the most stable among the three acylated anthocyanins synthesized.