Effects of Heat Moisture Treatments on the Digestibility and Physicochemical Properties of Various Rice Flours

Abstract

Heat moisture treatment (HMT) is a processing method used to improve the physicochemical properties of starch. Here, to inform technology with respect to increasing resistant starch (RS) in rice, three rice flours with different starch structures-namely, Koshihikari, Koshinokaori, and Goami2 (GA2)-were treated at 120 ℃ and 14 %-26 % humidity and compared with cornstarch. HMT increased the RS content of all specimens, with GA2 showing a marked RS increase up to 11.0 %. HMT also increased the gelatinization temperature (T gel ) of all samples, as shown by differential scanning calorimetry, and RS content tended to increase with increasing T gel values. As shown by the increase in relative crystallinity by X-ray diffraction and change in the iodine absorption spectrum, HMT easily changed the starch structure in GA2, leading to increased RS. These results support GA2 as a suitable rice cultivar for bio-functional rice products such as low glycemic index foods.

Characterization of the New Amylopectin Long-chain Rice Cultivar Chou 2418 and Its Boiled Rice Grains

“…By contrast, the carbohydrate content in Chou 2418 was the lowest among all seven rice cultivars ( p < 0.05). A similar observation has been previously reported in a Korean ae mutant rice cultivar, Goami2 (Noro et al, 2018).…”