Age-dependent bioaccessibility of citrinin, ochratoxin A, and zearalenone in boiled white Rice: A comparative...

Mycotoxins frequently co-occur in staple foods such as rice, yet little is known about how age-related gastrointestinal changes influence their release during digestion. This study evaluated the bioaccessibility of citrinin (CIT), ochratoxin A (OTA), and zearalenone (ZEN) in cooked white rice using the standard INFOGEST protocols simulating adults and older adults digestion under single and mixed exposure scenarios. Gastric and intestinal bioaccessible fractions were quantified using a validated LC-MS/MS method. Significant differences in bioaccessibility were evaluated across age groups and exposure conditions. CIT exhibited higher intestinal bioaccessibility in older adults, while co-exposure consistently reduced its release compared to single exposure. OTA showed the opposite pattern, with co-exposure enhancing intestinal bioaccessibility, particularly in adults. ZEN displayed moderate gastric but negligible intestinal bioaccessibility across all conditions, consistent with its low aqueous solubility. To integrate chemical and physiological determinants of mycotoxin behavior, Principal Component Analysis (PCA) was performed using physicochemical descriptors (logP, pKa, water solubility) and bioaccessibility variables from both digestion models. Principal component 1 (PC1;75.2% variance) captured the solubility-lipophilicity gradient, separating CIT and ZEN, while PC2 (18.2%) reflected age-related digestive differences and mixture effects. PCA findings corroborated experimental observations, indicating that mycotoxin bioaccessibility is influenced by intrinsic chemical properties and age-dependent gastrointestinal physiology. Overall, this study provides mechanistic insight into how aging influences the gastrointestinal release of co-occurring mycotoxins, with important implications for exposure assessment in vulnerable populations.