A physiologically based in vitro test was performed by simulating human gastrointestinal tract to determine the effect of pH value and main digestive enzymes on the bioaccessibility of DDT and its metabolites (DDTs) in carrot. Distribution of DDTs between digestive juice and matrix was also studied. The results show that pH of gastric juice has a great impact on bioaccessibility of DDTs, with the maxima at the pH value of 2.15. In contrast, within the range of experimental concentrations, increasing the concentrations of pepsin, bile and pancreatin has no significant effect on bioaccessibility of DDTs. In the test, bioaccessibility of p,p′-DDE, p,p′-DDD, and p,p′-DDT were 12.4%, 10.9%, and 10.8% in stomach and 34.2%, 29.1%, and 32.3% in intestinal, respectively. Distribution of DDTs between digestive juice and matrix indicates that DDTs in the digestive solution did not reach saturation during digestion processes. Partition coefficients between the digestive solution and digested carrot were 0.14, 0.14,and 0.13 in gastric solution and 0.67, 0.54, and 0.66 in intestinal solution, respectively.
