Abstract: In this study, low-temperature discharge plasma was used to degrade Ochratoxin A (OTA) in raisins, so as to study the effects of initial concentration and discharge voltage on the OTA degradation rate in raisins at different times. The results indicated that OTA with an initial concentration of 50 μg/mL in raisins was completely degraded by plasma for 10 minutes at a discharge voltage of 75 kV. With the adoption of high performance liquid chromatography coupled with quadruple-orbitrap high resolution mass spectrometry, OTA degradation products treated with low temperature discharge plasma were detected and identified. Combined with first-level and second-level mass spectrometry, it was inferred that the relative molecular masses were m/z 426.0715 (B) and m/z 158.1540 (C), respectively. The structures of the two main degradation products and possible degradation paths for OTA were detected and identified. There was no significant change in the physico-chemical quality of raisins before and after plasma treatment, and the relative contents of most of the acids, aldehydes, alcohols and ketones did not show significant changes in the volatile substances, except for a significant decrease in the contents of 3-methylbutyric acid, acetic acid and caprylic acid in the acids, and a significant increase in the contents of formic acid, valeric acid, and 2-ethylhexanoic acid.The research results suggests that low temperature discharge plasma can effectively degrade OTA and has no significant effect on raisin quality, which can provide a reference for food degradation studies contaminated with OTA.

Key words: Low-temperature Discharge Plasma, OTA, degradation effect, product analysis