Improving the color stability and antioxidation activity of blueberry anthocyanins by enzymatic acylation with p-coumaric acid and caffeic acid. (August 2020) - Liu, Jingna
Abstract: In this work, p- coumaric acid and caffeic acid were grafted on blueberry anthocyanins through enzyme catalysis method to improve their colour stability and antioxidant activity. The acylation degrees of p- coumaric acylated anthocyanins (Co-An) and caffeic acid anthocyanins (Ca-An) reached 5.38% and 5.68%, respectively. The results from Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultraviolet visible spectroscopy and hydrogen nuclear magnetic resonance implied that p- coumaric acid and caffeic acid grafted on the 6-OH of glucoside and galactoside and the 5-OH of arabinose through esterification reaction. As revealed in the in vitro experiment on antioxidation activity and the experiment on colour stability, Co-An and Ca-An showed stronger antioxidant activity in DPPH assay and β-carotene bleaching assay and higher colour stability during storage at 25 °C, 40 °C and 60 °C than native blueberry anthocyanins. Graphical abstract: Image 1 Highlights: p -Coumaric acid and caffeic acid were grafted on blueberry anthocyanins through enzymatic method. The color stability and antioxidation activity of blueberry anthocyanins were definitely improved. The graft sites were on the 6-OH of glucoside and galactoside and the 5-OH of arabinose.