The improved thermal stability of anthocyanins at pH 5.0 by gum arabic

Gum arabic (GA) was studied to improve the thermal stability of anthocyanins. Solutions with 0:51 mg/mL anthocyanins at pH 5.0 were heated at 80 and 126 degrees C up to 80 mm with and without 10 mg/mL GA. The half-life of thermal degradation of anthocyanins at 80 and 126 degrees C was increased by 2.0 and 1.8 times, respectively, after adding GA. The residual concentration of anthocyanins with GA was 1.02 and 135 times higher than that without GA after 30-min heating at 80 and 126 degrees C, respectively. The DPPH and ABTS free-radical scavenging capacities and ferric reducing power after heating anthocyanin solutions with GA at 126 degrees C for 30 min were significantly higher than those without GA. Fluorescence spectroscopy data suggested the formation of complexes between anthocyanins and GA. Zeta-potential data suggested the formation of complexes by hydrophobic attraction. Stable particle size and zeta-potential of GA with and without anthocyanins were observed after heating. This study indicated that the assembled GA nanostructures significantly reduced the thermal degradation of anthocyanins at pH 5.0. (C) 2015 Elsevier Ltd. All rights reserved.