The Impact Of Combination Of Heat Moisture Treatment And Germination On The Physicochemical Properties And Digestibility On Red Rice Starch

Abstract

The objective of this study is to investigate the impact on the changes in physicochemical properties as well as the formation of the resistant starch of red rice starch under germination process followed by heat-moisture treatment. Microstructure, physicochemical properties, and digestibility of starches isolated from five samples with different in period of germination (6, 12, 18, 24 hours) combined with heat-moisture at 100oC for 6 hours (Control, HMT06, HMT12, HMT18, and HMT24) were investigated. The five isolated starch samples were high purity starches with the application of starch isolation by soaking with 0.2% NaOH. The X-ray diffraction of crystallinity of all samples showed the A-type with the peak at around 17, 18, and 23o, 2θ. HMT reduced the swelling power from, and viscosities to compare with native starch, whereas the pasting temperatures, and solubility of treated red rice starch was higher than the native one. Furthermore, after germinate a period of time, the swelling power tend to be increase which is inversed proportionally to solubility, and viscosity. The percentage of SDS and RS tended to increase after HMT but decreased by the expansion of germination period. The RS of the native and HMT starch increased from 14.72% to 30.39%, respectively, whereas the percentage of SDS was indicated to have no change during germination. Germination and HMT were the low-cost, environmental friendly methods that physically modified the flour and starch to lower the digestibility, deceases blood sugar level export due to its high dietary fiber and RS amount.