影响胡萝卜中滴滴涕及其代谢物生物有效性的因素

Factors Affecting Bioaccessibility of DDT and Its Metabolites in Carrot

采用基于生理学的体外实验,通过模拟人体的胃和小肠环境,研究胃液pH值、胃肠中的主要消化酶对胡萝卜中滴滴涕及其代谢物(总称DDTs)生物有效性的影响及DDTs在胃肠消化液和胡萝卜基质之间的分配.结果表明:胃液pH值对DDTs的生物有效性有较大影响,在pH值为2.15时,达到最大值;在实验范围内,胃蛋白酶、胆汁盐和胰酶的浓度增大对DDTs的生物有效性没有显著影响.p,p-′DDE,p,p-′DDD和p,p-′DDT在胃和小肠中的生物有效性分别为12.4%,10.9%,10.8%和34.2%,29.1%,32.3%.DDTs在胃肠消化液和基质之间的分配表明,在消化过程中DDTs在胃肠溶液中的浓度没有达到饱和状态,在胃液和胡萝卜中的分配系数分别为0.14,0.14和0.13,在小肠液和胡萝卜中分别为0.67,0.54和0.66.

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.