Abstract: In this study, the effect of ochratoxin A (OTA) concentration and discharge voltage on the degradation of OTA in artificially contaminated raisins by low-temperature discharge plasma was explore. The results indicated that OTA in raisins contaminated with 50 μg/mL OTA was completely degraded by plasma treatment for 10 minutes at a discharge voltage of 75 kV. The degraded products of OTA were detected by high performance liquid chromatography-quadruple-electrostatic field orbitrap high resolution mass spectrometry. Based on the primary and secondary mass spectra, two major degraded products with m/z 426.071 5 (B) and m/z 158.154 0 (C) and the possible degradation pathway of OTA were speculated. There was no significant change in the physicochemical quality of raisins before and after plasma treatment, and the relative contents of most acids, aldehydes, alcohols and ketones did not significantly change, except for a significant decrease in the contents of 3-methylbutyric acid, acetic acid and caprylic acid among acids, and a significant increase in the contents of formic acid, valeric acid, and 2-ethylhexanoic acid. The research results suggest that low temperature discharge plasma can effectively degrade OTA while having no significant effect on raisin quality, which can provide a reference for OTA degradation in contaminated foods.

Key words: low-temperature discharge plasma; ochratoxin A; degradation efficiency; product analysis