Effect of cooking and other treatments on residual kojic acid in shrimps

Abstract

Recently, the tumorigenicity of kojic acid, which is widely used in foods and cosmetics in Japan, was reported. The present study was carried out to clarify the effect of cooking, e.g., washing, preservation methods, and boiling, on the residual amount of kojic acid in northern shrimps with shells, which were treated with a solution of a commercial preparation of kojic acid. Refrigeration and subsequent thawing decreased the amount of kojic acid in the shell and meat of northern shrimp. Kojic acid appeared to be released during thawing. When the shrimps were washed, the amount of kojic acid in the meat was the same as that in the meat of unwashed shrimp. Therefore, washing did not affect the residual amount. When the shrimps were stored in a refrigerator, the amount of kojic acid in the meat was greater than that in shrimp meat stored at -80°C. Boiling the shrimp significantly decreased the amount of kojic acid in the shell and meat. It was considered that 80 ~ 90% of the kojic acid in the total shrimp was removed by boiling.