Abstract
The effect of acetic acid on the properties of cooked rice was studied. A sensory test Revealed that rice cooked with water containing 0.1 M of acetic acid was more glossy, transparent, sticky and soft than rice cooked only with water (control). A decrease in hardness and increase in stickiness were shown by a texturometer with increasing concentration of acetic acid. The amount of glucose contained in the rice cooked with acetic acid was more than that of the control, although not depending on the concentration of acetic acid. In the case of free amino acids, only a small increase was found with increasing concentration of acetic acid. The amounts of solids, total nitrogen and bound amino acids contained in the washing solution of the cooked rice increased with increasing concentration of acetic acid, while the amounts of reducing sugars increased, but did not depend on the concentration of acetic acid. The increases in the amounts of those components in the cooked rice after washing were similar to those of the washing solution. In a model cooking experiment, the weight of rice increased with increasing concentration of acetic acid above 60°C. Furthermore, the amounts of reducing sugars and protein contained in the cooking solution were increased by acetic acid, the increase in the amounts of protein strongly depending on the concentration of acetic acid.
