Slowly digestible starch prepared from rice starches by temperature-cycled retrogradation

The temperature-cycled retrogradation of rice starch used to prepare slowly digestible starch was investigated in this study. Our results showed that a maximum slowly digestible starch content of 51.62% was obtained from waxy rice starch at the optimal tested conditions: temperature cycles of 4/25 °C, at intervals of 24 h, and 7 days of storage. The results also indicated that there was a higher onset temperature (To), a narrower melting temperature range (Tc − To), and a higher ratio (1047 cm−1/1022 cm−1) of the slowly digestible starch products prepared under the temperature-cycled condition than that under the isothermal retrogradation. Furthermore, it was evident that the in vitro glycemic index of slowly digestible starch products with temperature-cycled retrogradation was reduced more than that with isothermal storage. These results suggest that the temperature-cycled retrogradation is applicable to prepare the high yield of slowly digestible starch from waxy rice starch.