An application of image analysis for the study of kinetics of hydration of milled rice in hot water

Abstract

Two dimensional image analysis was carried out on basmati rice to determine the hot water hydration kinetics. A miniature water bath (105×55×15mm) was fabricated to process the rice grains under the CCD camera and on-line images were obtained at regular intervals of the hot water hydration process at four temperatures from 60 to 75°C. Two-dimensional projected area office grains was converted into swelling ratios for suitability of comparison of the swelling at different temperatures. The reaction rate constant and the activation energy for the hot water hydration were obtained from the swelling data. The activation energy was 38.213 kJ/mole and was comparable with other processes reported in the literature. The hydration data was further analysed to obtain a polynomial equation to correlate swelling ratios in terms of heating time and temperature. This study helps in obtaining the swelling parameter of rice during cooking to be used in the design of continuous cookers.