Identification and toxicological analysis of products of patulin degradation by Pichia caribbica

Increasing patulin contamination in fruits and fruit-derived products has become a major challenge for the food industry. Biological methods of patulin control have an important role to play owing to their safety and efficiency. In this study, we used the yeast Pichia caribbica to degrade patulin effectively. The intermediate degradation products of patulin by P. caribbica were identified as (E)- and (Z)-ascladiol using high performance liquid chromatography and liquid chromatography-tandem mass spectroscopy. Only (E)-ascladiol was detected in the products of patulin degradation by intracellular enzymes. Toxic analyses on Escherichia coli Top10 cells, Arabidopsis thaliana, and human esophageal epithelial cells (Het-1a) showed that the intermediate degradation product ascladiol and the final degradation products were significantly less toxic and almost non-toxic compared to patulin (p < 0.05), respectively. Furthermore, toxicological analysis revealed that ascladiol and the final degradation products induced very little reactive oxygen species accumulation in Het-la cells. Further toxicological analysis revealed that ascladiol and the final degradation products induced cell apoptosis to a lesser extent and did not significantly inhibit cell proliferation (p > 0.05) compared to patulin. Analysis of the characteristics and toxicity of the degradation products of patulin by P. caribbica demonstrate that ascladiol is less toxic and the final degradation products are not poisonous, therefore patulin detoxification strategies using P. caribbica are good approaches to limit the patulin risks.