Microwave reheating increases the resistant starch content in cooked rice with high water contents

• Published in: International journal of biological macromolecules 2021-08, Vol.184, p.804-811
• Main Authors: Liu, Ting, Zhang, Binjia, Wang, Lili, Zhao, Siming, Qiao, Dongling, Zhang, Liang, Xie, Fengwei
• Format: Article
• Language: English
• Subjects: Digestibility; Microwave treatment; Rice starch
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2021.06.136

This study explored how microwave reheating (to about 73 °C at different power levels) affects the microstructure and digestion characteristics of cooked rice with different water contents (1.1 and 1.5 times that of rice in weight). Irrespective of water content, mainly the V-type crystallites remained after microwaving reheating, with slight changes in other multi-scale structural features. Only at a relatively high water content (1.5) and with a power level high enough could short-range order be reduced. Such microwave reheating increased the digestion resistance of cooked rice. At a water content of 1.1 times, increasing the microwave power led to a decreased rapid digestible starch (RDS) content and an increased resistant starch (RS) content. With a higher water content (1.5), the enhancement of digestion resistance with higher microwave power was less significant but still, a reduced slowly digestible starch (SDS) content and a higher RS content were observed. [Display omitted] •Cooked rice with high water contents were microwaved at different power levels.•V-type crystallites remained after microwaving reheating.•Microwave reheating increased the digestion resistance of cooked rice.•Rice with 110% water content had increased RS content with reduced RDS content.•Rice with 150% water content had increased RS content with reduced SDS content.