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

Abstract:

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%.