食品中重要B族黄曲霉毒素生物可及性体外消化模型的构建

Development of an in vitro digestion model for assessing the bioaccessibility of aflatoxin B group in foods

目的构建黄曲霉毒素B1（AFB1）和B2（AFB2）生物可及性体外消化模型并进行验证。方法体外条件下，模拟胃肠道生理消化过程，研究消化时间（长、中、短）、进食状态（禁食、介于禁食及半饱食、半饱食、介于半饱食及饱食、饱食状态）、人工消化液体积（高、中、低）、人工消化液pH值（高、中、低）、同时进食的多种食物成分等因素对AFB1和AFB2在口腔、胃和小肠中的生物可及性的影响，确定其生物可及性体外消化模型最优技术参数，并用真菌毒素吸附剂和样品对模型进行验证。结果经过优化，AFB1从食物基质中释放到唾液、胃液、十二指肠液和胆汁中浓度达最高的最佳消化时间分别是6min、1．5h和2．5h；胃液、十二指肠液的最佳pH值分别是1．1和7．5；唾液、胃液、十二指肠液、胆汁的最佳体积分别是7、13、12和6ml；AFB，从食物基质中释放到唾液、胃液、十二指肠液和胆汁中浓度达最高的最佳消化时间分别是6min、2．5h和2．5h；胃液、十二指肠液的最佳pH值分别是1．1和7．8；唾液、胃液、十二指肠液、胆汁的最佳体积分别是5、12、13和6ml；AFB。和AFB：的生物可及性均在禁食状态下最高，分别为83．1％和89．3％，并随着胃内容物的增加而降低，但当胃内容物达到半饱食状态时，即使增加胃内容物量，生物可及性的变化不大，半饱食到饱食状态AFB．的生物可及性由72．8％下降到71．5％，AFB：由78．3％下降到76．9％。叶绿素和活性炭分别是降低AFB．和AFB，的生物可及性最强的吸附剂，生物可极性分别降低到0．8％和1．3％。结论构建的体外消化模型稳定、重复性好，完全可以满足对食品中B族黄曲霉毒素生物可及性的研究。

Objective To develop and validate an in vitro digestion model for assessing the bioaccessibilities of some important mycotoxins of aflatoxin B group （ aflatoxin B1 and aflatoxin B2 , AFB1 and AFB2 ）. Methods Using simulating gastrointestinal physiological digestion process, the effects of digestion time （long, medium and short）, the fasting and feeding status （fasting, between fasting and semi-feeding, semi-feeding, between semi-feeding and feeding , feeding states） , the volume and pH （high, medium and low） of digestive solution, as well as other food ingredients ingested along with aflatoxin B group from mixed foods on bioaccessiblities of AFB1 and AFB2 in the mouth, stomach and small intestine were studied. The optimal technical parameters of the model were identified and the model was validated with mycotoxin adsorbents. Results The optimal conditions of AFB1 releasing from the ingested foods at the highest concentration in gastrointestinal tract were as follows： digestion time of 6 rain, 1.5 h and 2. 5 h in mouth, stomach and duodenum, respectively;the optimal pH values of 1.1 and 7.5 for gastric juice and duodenal fluid; the volume of 7, 13, 12 and 6 ml for saliva, gastric juice, intestinal fluid and bile, respectively; the optimal conditions of AFB2 releasing from the ingested foods at the highest concentration in gastrointestinal tract were as follows： digestion time of 6 min, 2. 5 h and 2. 5 h in mouth, stomach and duodenum, respectively;the optimal pH values of 1.1 and 7.8 for gastric juice and duodenal fluid; the volume of 5, 12, 13 and 6 ml for saliva, gastric juice, intestinal fluid and bile, respectively. The bioaccessibilities of bothAFB1 and AFB= were highest at the fasting state （83. 1% and 89.3% respectively）. The bioaccessibilities decreased with the increasing of stomach contents, but the changes in bioaccessibility were not significant when the stomach contents reached the semi-feeding state or more. From semi-feeding to feeding state, the biocessibilities of AFBI decreased from 72. 8% to 71.5% and AFB2 decreased from 78. 3% to 76. 9%. Chlorophyll and activated charcoal were the strongest absorbent in reducing the bioaccessibilities of AFB1 and AFB2 , and the bioaccessibilities decreased to 0. 8% and 1.3% respectively. Conclusion The in vitro digestion model developed in the present study is stable and reproducible, and meets the requirements for assessing the bioaccessibilities of AFB1and AFB2 in foods.