Estimation of acrylamide intake from cooked rice in Japan

Abstract

A bromo-derivatization gas chromatography mass spectrometry (GC-MS) method for quantification of acrylamide in cooked rice was established for the estimation of acrylamide intake from a staple food in Japan. Limit of quantification (LOQ) and limit of detection (LOD) of acrylamide were, respectively, 0.20 and 0.09 μg/kg for cooked brown rice, 0.17 and 0.07 μg/kg for cooked germinated brown rice, and 0.14 and 0.06 μg/kg for cooked polished rice. The rank order of acrylamide concentration in rice, cooked with two types of home-use rice cooker, was germinated brown rice > brown rice > polished rice. Of the home-use rice cookers, less acrylamide was formed with the newer multifunctional type. Less acrylamide was formed using a professional use cooker than with the two cookers for home use. These differences might be derived from differences in temperature history and/or contact of rice grains to the high temperature bottom surface of the cookers. Considered in the context of the amount of cooked rice consumed in Japan (337.7g/day on average), the acrylamide in cooked polished rice can be regarded as a minor factor in the total intake of acrylamide of the Japanese. Acrylamide formation in brown rice and germinated brown rice also occurs at very low levels, unless they are over-heated to the point of burnt rice.