Impact of cooking conditions on the properties of rice: Combined temperature and cooking time

Abstract

Changes in the properties of cooked rice under various cooking conditions were investigated. Waxy, low-, and high-amylose rice were subjected to treatment with different cooking temperatures (50, 70, 90 °C) for different cooking times (15, 30, 45 min). The results showed that cooking greatly increased the swelling behavior of waxy rice but decreased the swelling behavior and amylose leaching of low- and high-amylose rice. As the cooking temperature increased, rapidly digestible starch increased significantly for all rice products, whereas slowly digestible starch and resistant starch had a certain degree of reduction. Variation in the cooking time produced little effects on starch digestibility. Gelatinization temperature was positively correlated with temperature and time, whereas gelatinization enthalpy was negatively correlated with temperature and time. Pasting properties of all rice products decreased significantly as cooking temperature and time increased. The study showed that both cooking temperature and cooking time had significant impacts on the physicochemical properties and starch digestibility of waxy, low-, and high-amylose rice to various extents. Temperature had a more pronounced impact on the extent of change to the in vitro digestibility than did cooking time.