Improving the Hydrophobicity of Blueberry Anthocyanins through Enzymatic Acylation Modification

Abstract

In order to solve the problem of poor hydrophobicity of anthocyanins, in this paper, the blueberry anthocyanin was acylated with ferulic acid and caffeic acid, and the structure, hydrophobicity and antioxidant activity of related products were analysed. The FTIR and UV-Vis analysis indicated that ferulic acid and caffeic acid were grafted on the -OH of the glycosyl of the blueberry anthocyanins through acylation reaction, and the acylation degree of the anthocyanins acylated with ferulic acid (Fe-An) and caffeic acid (Ca-An) was 3.65% and 3.71%, respectively. Meanwhile, the total anthocyanidin content was decreased from 370.2 mg/g (Na-An) to 219.2 mg/g (Fe-An) and 222.18 mg/g (Ca-An), respectively. In addition, the hydrophobicity and antioxidant activity of blueberry anthocyanins were significantly improved after acylation with the two phenolic acids. The octanol-water partition coefficient (KOW) was increased from −0.20 (Na-An) to 0.66 (Fe-An) and 0.78 (Ca-An), DPPH clearance increased from 66.3% (Na-An) to 68.4% (Fe-An) and 74.7% (Ca-An), and inhibition ratio of β-carotene bleaching increased from 63.1% (Na - An) to 85.5% (Fe-An) and 90.3% (Ca-An). The results show that the introduction of ferulic acid and caffeic acid significantly improve the hydrophobicity and antioxidant activity of blueberry anthocyanins, which will greatly expand the application of anthocyanins in high-fat foods.