*2.1. Material*

Betanin was purchased from Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Rice starch (RS, 10.64% moisture, 0.92% fat, 22.49% amylose, *w*/*w*) was obtained from Sigma-Aldrich Inc. (St. Louis., MO, USA). Potato starch (PoS, 9.78% moisture, fat not detected, 26.54% amylose, *w*/*w*) and pea starch (PeS, 10.47% moisture, 0.49% fat, 38.67% amylose, *w*/*w*) were purchased from Rogate Starch Company (Jiangsu, China). All other chemical reagents were of analytical grade and supplied by Aladdin Chemical Company (Shanghai, China). Distilled water was used throughout the experiments.
