0023-6152

AA00697606

4363547

This study was undertaken to determine the effect of types of cooking water on the palatability of Chinese japonica–type rice cultivars. Changes in physicochemical properties of rice affected by cooking water were also explored. Results showed that all cultivars had improved palatability depending on types of cooking water. When cooked in water with low total hardness and conductivity, the overall eating–quality of cooked rice presented higher palatability compared with cooked in water with high total hardness and conductivity. Moreover, the effect of improved palatability varied with cultivar, with highly palatable cultivar had a smaller effect, whereas poorly palatable cultivar had a greater effect. Hardness/adhesion (H/–H) ratio of cooked rice was declined by using cooking water with low total hardness and mineral content compared with tap water and the effect of changes in types of cooking water on H/–H ratio was small for highly palatable rice but were large for moderately and low palatable cultivars. Correlation analysis showed that total hardness and conductivity of cooking water had a negative tendency with overall eating-quality of cooked rice for the tested cultivars, i.e. the harder and the greater conductivity the cooking water, the poor the palatability. On the other hand, there was no relationship between pH value of cooking water in the range of the experiment and overall eating–quality of cooked rice for the tested cultivars. Total hardness and conductivity of cooking water showed a positive correlation between H/–H ratio and breakdown and there was no constant relationship between pH value and physicochemical properties of rice. The standard partial regression coefficient against overall eating–quality was the highest for H/–H ratio in cooked rice (–0.689). Thus, the improvement in palatability by types of cooking water could be attributed to the reduced H/–H ratio of cooked rice due to the lower calcium content in rice.