Basic investigation on fluorescence properties of soybeans in response to different external defects.

To investigate the fluorescent properties of defects found on the surface of harvested soybeans, the front-face method was used to measure the Excitation Emission Matrix (EEM) on 106 samples of two varieties of soybeans to evaluate fluorescent properties according to defect type. The EEM showed four main peaks at Excitation/Emission (Ex/Em): 350-430 nm/420-510 nm, 410-450 nm/460-530 nm, 260-290 nm/300-350 nm and 210-230 nm/310-340 nm. In the Diseased, Pest, and Denatured (Black) soybeans, the above four main peaks were weakened. In addition, in the Denatured (White) Ex/Em: 260-290 nm/300-350 nm specific peak was observed. Furthermore, dimensionality reduction was performed using principal component analysis (PCA), and visualization was performed according to defect type on a two-dimensional plot. The loading of the first and second principal components were also visualized.