Pasting, cooking, and digestible properties of Japonica rice with different amylose contents

Pasting, cooking, and digestible properties of Japonica rice with different amylose contents were investigated. Low-, medium-, and high-amylose Japonica rice (waxy, 18.8% amylose content, and 33.3% amylose content) were cooked and evaluated for water absorption, volume expansion, molecular mobility, microstructure, crystalline structure, and starch digestibility. The results showed that high-amylose rice had lower peak viscosity but higher pasting temperature and final viscosity than low- and medium-amylose rice. After cooking, high-amylose rice showed slightly higher water absorption ratio but lower volume expansion ratio than the other two rice varieties. Water was more evenly distributed in cooked low- and medium-amylose rice than in cooked high-amylose rice. After cooking, starch in low- and medium-amylose rice kernels almost lost the entire crystalline structure, but starch of cooked high-amylose rice still exhibited strong V-type crystallinity. Cooked high-amylose rice contained higher content of resistant starch than cooked rice of other two varieties.