Direct Acylation of Cyanidin-3-Glucoside with Lauric Acid in Blueberry and Its Stability Analysis

Cyanidin-3-glucoside is an anthocyanin that is abundant in blueberry. Lauric acid was used as the acyl donor in the acylation of cyanidin-3-glucoside. Preparative high performance liquid chromatography was used to separate and purify the acylated cyanidin-3-glucoside, the acylated rate was 30.78%. Fourier transform infrared spectroscopy and liquid chromatography mass spectrometry were used to confirm the basic structure of cyanidin-3-glucoside. Lauric acid was combined with cyanidin-3-glucoside. Lauric acid reacted with the glucoside's primary hydroxyl group and removed a molecule of water, thereby resulting in the obtained structure. The compositions of the unacylated cyanidin-3-glucoside and acylated cyanidin-3-glucoside were compared under different temperatures and under illumination. The effects of different concentrations of additive compounds on the stability of acylated cyanidin-3-glucoside were compared. Stability of acylated cyanidin-3-glucoside was obviously higher than that of the unacylated cyanidin-3-glucoside because of the higher stability of the ester group than the hydroxyl group. The primary hydroxyl esterification of glucoside improved cyanidin-3-glucoside.