Assessment of ochratoxin A stability following gamma irradiation: experimental approaches for feed detoxification perspectives

作者：Mehrez A^*; Maatouk I; Romero Gonzalez R; Ben Amara A; Kraiem M; Frenich A Garrido; Landoulsi A

来源：World Mycotoxin Journal, 2016, 9(2): 289-298.

DOI：10.3920/WMJ2013.1652

• ochratoxin A
• food matrix
• radiolysis
• detoxification

The present study evaluated the effect of gamma irradiation on the stability of ochratoxin A (OTA) under various conditions. The effects of the physical state of OTA (solid vs aqueous), initial OTA concentration, irradiation dose and dose rate as well as the presence of model substances simulating food matrix compounds on OTA radiostability were investigated. First, pure OTA with and without food model compounds including alpha-D-glucose (monosaccharide), Methyl alpha-D-glucopyranoside (starch) and the amino acid derivatives N-alpha-acetyl-L-lysine methyl ester and N-alpha-acetyl- L-cysteine methyl ester (protein models) were irradiated with doses of 2, 4 and 8 kGy applied at 15.117 and 108.24 Gy/min. Secondly, artificially OTA-contaminated wheat with different moisture content (11, 14 and 16%) was irradiated with doses of 2, 4 and 8 kGy applied at 63.39 Gy/min. Residual OTA levels were analysed using ultra-high performance liquid chromatography coupled with tandem mass spectrometry. Solid OTA (50 and 3,200 ng/ml) showed great irradiation stability, even with irradiation doses up to 8 kGy. Under dry conditions, the presence of food model components did not affect OTA radiostability. However, in an aqueous solution, complete reduction was achieved at the initial OTA concentration of 50 ng/ml and irradiation dose of 2 kGy. Applying gamma irradiation to cereal-based food model systems produced a significant OTA reduction (5,000 mu g/kg) of 47.2% in moistened wheat kernels (16%) with an absorbed dose of 8 kGy but failed to reduce the OTA content of low moisture content wheat (11%). These model experiments offered a useful tool to assess the main key factors affecting gamma irradiation-induced OTA reduction. Gamma irradiation is promising since the irradiation doses applied could partially reduce OTA contamination. Nevertheless, its efficacy was largely affected by initial moisture content and could be dangerous if toxic by-products are produced or nutritive quality is lost and needs further study.

• 出版日期2016