Correlations between quality and proportional extent of milling in optical images of rice stained using the NMG method

Abstract

In the present study, milling yield of rice was classified into 5 gradients. Samples were stained using the NMG method, and images were taken using a digital camera. A method using shadowed areas of endosperm, aleurone layer and bean layer to determine the proportional extent of milling was investigated. Furthermore, the relationship between milling yield, results of measurement by near-infrared spectroscopy, appearance, determination of physical properties of the cooked rice and gelation were investigated. The results suggest that milling degree closely correlates with milling yield and is related to palatability, increased whiteness, grain damage and grain color. The correlation between milling degree, taste and degree of whiteness was clarified.