Investigation on the stability of deoxynivalenol and DON-3 glucoside during gastro-duodenal in vitro digestion of a naturally contaminated bread model food

Deoxynivalenol (DON) and its main conjugate derivative, DON-3 glucoside (DON-3G), are Fusarium mycotoxins frequently occurring in cereal and cereal-based products destined to human consumption. In this paper, we investigated the stability of DON and DON-3G along the gastric and duodenal-jejunal tract (GI) by submitting a bread food naturally contaminated with both mycotoxins to in vitro digestion experiments. Gastro-duodenal digestion fluids were collected at different time-points along the whole digestion process (gastric and duodenal phases) and mycotoxin content was determined by LC/High Resolution Mass Spectrometry. Our findings show a rather stable behaviour displayed by DON during gastric digestion, whereas a 43% DON decrease was recorded during the passage from the gastric to the duodenal compartment. Ultimately, the apparent and actual bioaccessibility was calculated for DON with values ranging between 34 and 57%, respectively. Data obtained for DON-3G showed no significant differences between the beginning and the end of the gastric phase, whereas a remarked increase of this conjugated mycotoxin was highlighted during the passage in the duodenal compartment. Our results suggest that a conversion of DON in DON-3G is likely to occur during gastro-duodenal digestion of contaminated bread.