The effects of a combination of acid and heat-moisture treatment on formation of resistant starch (RS)
and characteristics of high-amylose, normal and waxy rice starches were investigated in this study.
The degrees of polymerization of the rice starches treated with citric acid, lactic acid or acetic acid were
significantly reduced as compared to the native starches. The RS contents of acid and heat-moisture treated
rice starches were in a range of 30.1–39.0%, significantly higher than those of native rice starches
(6.3–10.2%) and those of heat-moisture treated rice starches (18.5–23.9%). The acid and heat-moisture
treatments reduced swelling power and viscosity, but increased solubility of the starches, while the crystalline
structure did not change. Among the organic acids used, citric acid had the most impact on starch
characteristics and RS formation, followed by lactic acid and acetic acid. The results are useful in production
of RS for functional food application.