Abstract: In recent years, with the aggravation of water and soil pollution, the situation of cadmium pollution in rice has got more and more serious in China. The primary route of cadmium exposure in humans is dietary digestion, and it is absorbed in the small intestine. In this study, the cadmium contents in contaminated raw and cooked rice were analyzed, and then the bioaccessibility of cadmium after digestion was determined by using an in vitro oral-gastric-intestinal digestion model. Finally, a Caco-2/HT-29 cell co-culture model was used to evaluate the effect of (-)-epigallocatechin-3-gallate (EGCG) on the absorption and transport rates of cadmium in the digestive fluid of cooked rice. The results indicated that cadmium bioaccessibility in the gastric phase was (73.58 ± 1.92)% after simulated digestion for 2 h, and (36.29 ± 1.25)% in the small intestinal phase after simulated digestion for 7 h. Moreover, EGCG significantly reduced the absorption and transport rates of cadmium in the digestive fluid of cooked rice, at 21.82 and 43.64 μmol/L by 5.56% and 13.89% compared with the control group, respectively. This study may provide a new insight into dietary intervention for in general populations in cadmium exposure regions.

Key words: cadmium, cooked rice, (-)-epigallocatechin-3-gallate, Caco-2/HT-29 cells co-culture, absorption and transport rate