体外仿生消化在华贵栉孔扇贝(Chlamys nobilis)体内镉的生物可给性中的应用

Preliminary Application of in vitro Bionics Digestion Model for Bioaccessibility of Cd in Chlamys nobilis

中文关键词: 镉  体外仿生消化  生物可给性

英文关键词: Cadmium  in vitro bionics digestion model  Bioaccessibility

中文摘要:

      体外仿生消化是目前研究食品中污染物生物可利用性的有效手段之一。将体外仿生消化法应用于华贵栉孔扇贝(Chlamys nobilis，以下简称扇贝)中镉(Cd)生物可给性分析的前处理工序(Cd暴露水平较高)，即模拟人体消化环境，加入消化液所含有机物和无机物(含消化酶)，探讨扇贝体内Cd在胃肠中的释放机制。结果显示，各体外仿生消化液单独作用于扇贝时，Cd溶出平衡时间顺序依次为：仿生唾液>胃液>胆汁>十二指肠液，而溶出量大小顺序为：胃液>胆汁≈十二指肠液>唾液，仅十二指肠液和胆汁中Cd溶出时的lnC–t呈线性相关(R2=0.9530和R2=0.8891)。因此，Cd在唾液或胃液中溶出时的关键因子是pH，但在十二指肠液、胆汁和全过程仿生消化液中，消化酶起决定作用。样-液比在1∶10–1∶120 (g/ml)之间时，扇贝体内Cd溶出率没有显著差异，即样-液比对Cd的生物可给率影响不大。体外全仿生消化结果显示，扇贝内约有70%的Cd释放溶出，即扇贝消化糜中Cd的最大生物可给率为70%。

英文摘要:

      In vitro whole-bionic digestion model has been an effective approach to study the bioaccessibility of contaminants in food. Due to the high exposure of cadmium (Cd), samples of Chlamys noblis were pretreated with in vitro bionic digestion for the bioaccessibility of Cd. The releasing mechanism of Cd in C. noblis was investigated in a simulated gastrointestinal tract environment where the chyme was obtained at 37℃ through digestion with enzymes and inorganic substances in saliva, stomach, and intestine. The samples of C. noblis were treated with four digestion juices separately, including saliva, gastric juice, duodenal juice, and bile. It was found that the dissolution equilibrium time of Cd in the digestion juices followed the order: saliva < gastric juice < bile < duodenal juice. In the bionic experiments, Cd dissolution quantity showed the pattern: gastric juice > bile ≈ duodenal juice > saliva. There was a linear correlation between the logarithm of concentration (lnC) and its corresponding dissolved time (t) in duodenal juice (R2=0.9530) and in bile (R2=0.8891), however, no correlation was found in saliva or gastric juice. pH may be the key factor of Cd dissolution in the bionic digestion with saliva and gastric juice, and digestive enzymes played the essential role in the digestion with duodenal juice, bile, and in vitro whole-bionic digestion. There was no significant difference when the sample-to-fluid ratio changed from 1:10 to 1:120 (g/ml), implying that this ratio might only slightly affect the bioaccessibility. The releasing ratio of Cd in C. noblis was 70% and the maximum bioaccessibility in C. noblis chyme was also 70%.