Effect of size reduction on yellow soybean seed characterization based on colorimetry

Soybean seed, which is generally yellow in color, is the primary product of soybean plants sold in Indonesian market. To characterize non-destructively, it is necessary to understand the extent to which physical treatment, including size reduction, may affects the color characteristics. Therefore, this study aimed to determine the effect of size reduction of soybean seeds on its color parameters. A completely randomized design was performed with particle size factor with five levels and variety factor with four levels. Particle size included: intact seed; >595; 595-250 μm; 250-145 μm; and <145 μm of particle size, while variety included Anjasmoro; Argomulyo; Grobogan and soybean seed obtained from local market. Color parameters which used were L, a*, b*, Hue and C*. The ANOVA with Duncan multiple range test (α=0.05) and PCA were performed to analyze the effect of color parameters to sample classification. The results showed that the L and Hue value was significantly different (p<0.05) for all particle size. The smaller the particle size, the greater the L value and the smaller the Hue value. The L value was also significantly different (p<0.05) for all varieties and was able to classify all varieties. The PCA analysis result in up to 96% of PC-1 and PC-2 showing that size reduction was able to classify all samples based on all parameters; distinct classification of Anjasmoro and local market soybean can be observed. The yellowish color that represented by a* value, showed the higher distance than other parameters.