カカオ製品のクロム濃度の変動

抄録

Several powdered food samples were purchased from local retail shops in Osaka area or by a mail order, and their chromium (Cr) concentration determined by inductively coupled plasma mass spectrometry were compared the values cited in the Standard Food Composition Table of Japan (2015). The analytical values were almost identical to the cited values. Among the samples, pure cocoa powder showed a marked variation in the Cr concentration (14 to 187 μg/100 g). To examine the cause of the variation in the Cr concentration in cacao bean products including pure cocoa powder, the Cr concentration was determined in a large number of chocolate samples. In the 8 chocolate samples purchased from a confectionery company (Valrhona, Paris), a strong correlation (r = 0.88) was observed between the Cr concentration and the cacao content. Chromium concentration in 22 samples of single origin chocolate purchased from another confectionery company (Meiji Co., Ltd, Tokyo) was 3 to 22 μg/100 g. Since the variation of Cr concentration in pure cocoa powder is much greater than that of cacao mass, which is estimated by the Cr concentration of chocolate, the high Cr concentration in pure cocoa powder is estimated to be assocated with a contamination of Cr in the manufacturing process of pure cocoa powder from cacao mass.