Structure and functional characteristics of starch from different hulled oats cultivated in China

Abstract

This work aimed to evaluate the structure and functional characteristics of starch from ten hulled oat cultivars grown in different locations in China. The protein, phosphorus, amylose, and starch contents were 0.2–0.4 %, 475.7–691.8 ppm, 16.2–23.0 %, and 93.6–96.7 %, respectively. All the starches showed irregular polygonal shapes and A-type crystallization with molecular weights ranging from 7.2 × 107 to 4.5 × 108 g/mol. The amounts of amylopectin A (DP 6–12), B1 (DP 13–24), B2 (DP 25–36), and B3 (DP > 36) chains were in the ranges of 10.3–16.0 %, 54.5–64.8 %, 16.5–21.1 %, and 4.9–13.1 %, respectively. The starches differed significantly in gelatinization temperatures, pasting viscosity, solubility, swelling power, rheological properties, and digestion parameters. The results revealed that the larger particle size could increase the peak viscosity of the starch paste. The presence of phosphorus increased the gelatinization temperature and enhanced the resistant starch content. The starch granules with higher crystallinity contained a higher proportion of phosphate, which increased final viscosity and setback viscosity but decreased rapidly digestible starch. Overall, oat starch with a high phosphorus content could be used to prepare low-glycemic-index food for diabetes patients.