Characterization and Comparison of Structure and Physicochemical Properties of Highland Barley Starch of Different Colors

Domesticated highland barley is an important starch reserve and has differently colored grains, owing to different genotype backgrounds and cultivation environments. In this study, black, purple, blue, and yellow highland barley varieties were planted under the same cultivation conditions, and their starch distribution, structural characteristics, and physicochemical properties were analyzed. The apparent amylose content was highest in the purple variety (20.26%) and lowest in the yellow variety (18.58%). The different varieties had three subgroups and A-type crystalline structures, but the particle size and relative crystallinity (25.67-27.59%) were significantly different. In addition, the weight average molecular weight (6.72 × 10⁷ g/mol), area ratio of APs to AP_L (2.88), relative crystallinity (27.59%), and 1045/1022 (0.730 cm^-1) of starch were higher in yellow highland barley (YHB), forming a stable particle structure and increasing the Tp and PV of its starch. A cluster heat map showed that starches from differently colored highland barley vary in fine structure, water solubility, swelling power, and thermal and pasting properties. This study provides a reference for the high-quality breeding of colored highland barley and its utilization in food and non-food industries.