Nondestructive distinction of producing area of black soybean [Glycine max] by the fluorescence X-ray with SPring-8

Recently, many cases of deceptive labeling of food origins have come to light, and the reliable display on the producing locality of crops is needed. Therefore, the technology which scientifically distinguishes the locality has been required. Then, the nondestructive analysis to discriminate locality of agricultural production with the large synchrotron radiation (SPring-8) was examined. Black soybeans were used as agricultural production. The fluorescence X-ray analysis of the sead coat of black soybeans could detect many kinds of trace elements such as Ca, Fe, Cu, Zn, Rb, Sr and etc.. However, Ca, Fe, Cu and Zn are applicated to soils as fertilizers or soil conditioner. It was considered that Rb and Sr were elements which were not affected comparatively with fertilizers in cultivation. Then, the possibility of the locality discrimination of black soybeans by Rb and Sr contents was examined. The component content in the minute spot could be measured, because the diameter of the X-ray was micro as 200 mum. We need to measure soybeans at several spots of the sead coat for getting their individual central values, because the components of them are not generally uniform. It was clarified that the number of measuring spot for reliable central values as individual was 4. Using the measuring method established in the last time, the locality discrimination between black soybeans produced at Hyogo Prefecture in Japan and those produced in China was carried out. By the measurement of the Rb content, it was difficult to discriminate between Hyogo Prefecture-products and China-products. As a result of the measurement of the Sr content, the Sr content in China-products was clearly higher than that in Hyogo Prefecture-products. As a conclusion, there is the possibility of nondestructive analysis to discriminate to the locality of agricultural products with the fluorescence X-ray irradiation of SPring-8.