Effectiveness of pulsed light treatment for degradation and detoxification of aflatoxin B-1 and B-2 in rough rice and rice bran

摘要

Aflatoxins primarily accumulate in the hull and bran layers of rough rice making these by-products of rice milling unsuitable for animal feed or human consumption. Contaminated rough rice is also a potential source of aflatoxin exposure to workers handling the grain during post-harvest storage and processing. Currently, no technologies are available to remove or detoxify these toxic and mutagenic fungal metabolites from contaminated rough rice. Pulsed light (PL) is a novel technology with the potential to degrade and detoxify aflatoxins in foods and their processing by-products. Rough rice was inoculated with Aspergillus flavus to produce aflatoxin B-1 (AFB(1)) and B-2 (AFB(2)) contamination, followed by PL treatments of 0.52 J/cm(2)/pulse for various durations. A PL treatment time of 80 s reduced AFB(1) and AFB2 in rough rice by 75.0% and 39.2%, respectively; while a treatment time of 15 s reduced AFB(1) and AFB2 in rice bran by 903% and 86.7%, respectively. Since PL treatments result in the degradation of aflatoxins in situ, the toxicity and mutagenic activity of the residual by-products of AFB(1) and AFB(2) after PL treatment were evaluated. Toxicity was estimated using the brine shrimp (Anemia sauna) lethality assay and mutagenicity measured by the fluctuation test with Salmonella typhimurum tester strains TA98 and TA100. The mutagenic activity of AFB(1) and AFB(2) was completely eliminated by PL treatment, while the toxicity of these two aflatoxins was significantly decreased. The obtained results suggest that PL technology has a promising potential to degrade, detoxify, and inactivate the mutagenic activity of aflatoxins in rough rice and rice bran. Published by Elsevier Ltd.