Abstract
The aim of this study was to elucidate the changes in rice microstructure based on the soaking conditions. We also investigated the relationship between rice microstructure and texture, such as the hardness and elasticity of cooked rice. This could eventually lead to a deeper understanding of the better flavour and taste of rice. Rice soaked for varying time periods (0, 20, 60, and 120 minutes) in water (temperature 10°C) was subsequently subjected to cooking-based experiments and analysed.
Scanning electron microscopy (SEM) images of cross-sections of cooked rice were obtained. From these, we observed uniform honeycomb structures and dense layers near the surface of the cooked rice.
The pore size of the structure increased with the increase in soaking time. An analysis of the texture on the cooked rice indicated that elasticity reduced with the increase in soaking time, and that stickiness and hardness reduced until the soaking time reached 60 minutes and increased at a soaking time of 120 minutes.
The honeycomb structure was quantified by the analysis of the SEM images. Based on this analysis, the average area of the honeycomb structure was found to be strongly dependent on the quantity of water in which the rice was soaked. In addition, the structure was believed to determine the elasticity of the cooked rice.
Finally, we suggest that the human sensory response, which is correlated to the texture of the cooked rice, can be analysed and predicted by observing the microstructure of the cooked rice.
