Pasting properties of rice marketed in Asian countries: a systematic study

In this study, the starch and protein pasting properties of 21 rice varieties collected from different parts of China were determined using a rapid viscosity analyzer, and the effects of salt concentration and pH on their pasting properties were investigated as well. The rice varieties exhibited diverse starch pasting properties. Further, the varieties of the indica subspecies exhibited more desirable starch pasting tendencies than did those of the japonica subspecies. Furthermore, differences in the salt concentrations and acid conditions caused no significant differences in the starch pasting properties. Additionally, the peak viscosity of the rice starches decreased at pH 4 and 4.5. The rice varieties also showed advantageous protein pasting properties, which could influence the overall pasting properties of the rice starches. Finally, among the 21 rice varieties, seven of the indica and two of the japonica subspecies exhibited excellent starch and protein pasting properties, while red, black, and brown color rice exhibited lower pasting properties.