Starch structure and digestibility of rice high in resistant starch

Starch digestibility and starch structure of a high-resistant starch (RS) rice (RS111) was compared to that of a wild rice type (R7954). RS111 exhibited high RS content and incomplete starch hydrolysis in both cooked rice and retrograded rice flour. High IRS rice RS111 had a higher lambda(max) of absorbance and blue value of iodine-binding starch complex and contained a higher percentage of intermediate chains of amylopectin than R/954. X-ray diffraction pattern of IRS isolated from cooked high IRS rice displayed a mixture of B- and V-type that was more resistant to starch hydrolysis by alpha-amylase. Resistant starch in RS111 is composed mainly of linear amylose and some low-molecular-weight amylopectin.