An integrated digestion-transport study of Citrinin, Ochratoxin A and Zearalenone from rice: Influence of matrix and turmeric on human exposure

Mycotoxins such as citrinin (CIT), ochratoxin A (OTA), and zearalenone (ZEN) frequently co-occur in rice, raising concerns about dietary exposure. This study investigated the gastrointestinal fate of CIT, OTA, and ZEN in white rice (WR), brown rice (BR), and turmeric-seasoned rice (WR + T, BR + T) after single and combined (mixture) exposure using the standardized INFOGEST static in vitro digestion model. Subsequently, intestinal transport of these mycotoxins in WR and WR + T under single and mixture exposure conditions was evaluated using Caco-2/HT-29MTX co-culture transport assays. Bioaccessibility, apparent permeability (P app ), mass balance, and predicted human fraction absorbed were determined. This work demonstrates that the gastrointestinal fate of CIT, OTA, and ZEN is influenced by both the food matrix and co-exposure conditions. CIT exhibited moderate to high bioaccessibility in WR when tested single (69.8%), but this decreased significantly in mixture (37.6%). Turmeric enrichment enhanced CIT release (87.6% single; 64.6% in mixture). OTA showed a moderate release (WR 57.0% single, 78.7% mixture), with patterns comparable to those observed with turmeric addition (59.2% single, 74.5% mixture). ZEN was essentially non-bioaccessible in WR/BR but increased markedly in the presence of turmeric. In transport assays, CIT showed delayed but convergent absorption (around 25% at 180 min across WR assays). Turmeric enhanced OTA transport by about 20% and increased P app values . ZEN showed the fastest transport, reaching 46%, and this was also amplified by turmeric. Predicted fractions absorbed categorized all three toxins as highly absorbed (>85%), reinforcing the potential for systemic exposure despite reductions in bioaccessibility due to matrix-effects. Rice type and turmeric reshape mycotoxin solubilization and epithelial transfer, but systemic uptake potential remains high for all three toxins. Integrating both bioaccessibility and intestinal absorption data is essential for risk assessment, since low bioaccessibility does not necessarily imply low systemic exposure when high intestinal permeability is considered.