Morphometric characterization of chalkiness in Mexican rice varieties by digital image analysis and multivariate discrimination

The opaque spot in the rice endosperm is called chalkiness; this characteristic has been recognized as agrain quality parameter for milling, and it is related to water retention. There is little scientific information about image analysis application (IAA) to characterize chalkiness development as pattern of the rice grain quality. In this work, chalkiness in the transversal section of polished grain of five rice varieties, using different parameters (form factor, fractal dimension concepts, angular second moment, lacunarity, entropy and color) was identified. The multivariate analysis indicated that the studied varieties presented morphometric characteristics that enabled it to be classified with 99.24% of accuracy. The results allowed the grouping by dendrogram analysis in two groups: 1) MorA-92, MorA-98, MorA-06, and 2) MF and MC, distinguishing between varieties, and demonstrating similar morpho-colorimetric chalkiness characteristic patterns between the analyzed rice varieties.