Reduction of ochratoxin A in oats and rice by twin-screw extrusion processing with baking soda

Abstract

Ochratoxin A (OTA) is one of the most important mycotoxins due to its widespread occurrence and toxicity, including nephrotoxicity and potential carcinogenicity to humans. OTA has been detected in a wide range of agricultural commodities and their processed products such as infant cereals and breakfast cereals. Extrusion processing, which is widely used in the manufacture of infant and breakfast cereals, may reduce mycotoxin levels to varying degrees. Hence, the effects of extrusion cooking process on the stability of OTA in spiked (100 μg/kg) oat flakes and rice flour was investigated by using a laboratory-scaled twin-screw extruder. In addition, the effect of twin-screw extrusion and addition of baking soda (0, 0.5, and 1.0% weight of total solids) on the reduction of OTA in oats and rice was investigated. The reductions of OTA in the artificially contaminated oat flakes upon extrusion cooking were in the range of 40–43% whereas the reductions in rice flour ranged from 78 to 82%. The reductions of OTA during extrusion with added baking soda were up to 65% and 72% in oats and rice, respectively. These results suggest that OTA in rice and oats may be reduced significantly by extrusion cooking process, which can be applied to commercial production of infant cereals and breakfast cereals. In addition, baking soda may also help to reduce OTA levels in oats during thermal processing.