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Research Project: New Sustainable Processing Technologies to Produce Healthy, Value-Added Foods from Specialty Crops

Location: Healthy Processed Foods Research

Title: Degradation kinetics of aflatoxin B1 and B2 in filter paper and rough rice by using pulsed light irradiation

item WANG, BEI - University Of California
item Mahoney, Noreen
item KHIR, RAGAB - University Of California
item MA, HAILE - Jiangsu University
item XINGRONG, LIU - Jiangsu University
item Pan, Zhongli

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: Aflatoxin is a group of highly toxic, mutagenic and carcinogenic compounds produced by Aspergillus flavus (A. flavus) and Aspergillus parasiticus (A. parasiticus). Among the various aflaxoxin species, aflatoxin B1 (AFB1) is the most potent teratogen mutagen and heparocarcinogen. AFB1 and AFB2 are always produced simultaneously by A. flavus. Aflatoxins are found in in many countries, especially in tropical and subtropical regions where the high temperature and humid climate allow for optimal growth of A. flavus, which produces aflatoxins. Rough rice, a main crop in these regions, is commonly contaminated with aflatoxins. With the FAO reporting that on a yearly basis 25% of grain crops are contaminated with mycotoxins. Therefore, there is a pressing need to develop methods that can effectively degrade aflatoxins. Our previous study revealed that PL treatment achieved an effective degradation of AFB1 and AFB2 in rice bran. The obtained results in this study showed that the degradation of AFB1 and AFB2 in filter paper and in rough rice followed the second-order reaction kinetics well. The initial concentration and power intensity had positive relationship with the reaction rate. The model developed in this study can be used to predict the final contents of AFB1 and AFB2 after PL treatment and provides important information for reducing the risk of aflatoxin contamination in rough rice.

Technical Abstract: Rough rice is susceptible to contamination by aflatoxins, which are highly toxic, mutagenic and carcinogenic compounds. To develop aflatoxin degradation technology for rice with the use of pulsed light (PL) treatment, the objective of this study was to investigate the degradation characters of aflatoxin B1 (AFB1) and B2 (AFB2) inoculated in filter papers and rough rice under PL treatment. A kinetic degradation study of AFB1 and AFB2 in filter papers was performed under PL irradiation at different initial concentrations (500, 250 and 100 ppb) of AFB1 and AFB2 and irradiation intensities (0.92, 0.52 and 0.30 J/cm2/pulse) of PL. First-order and second-order reaction models were applied to describe degradation of AFB1 and AFB2. Rough rice samples with initial AFB1 and AFB2 concentrations of 132.2 µg/kg and 44.9 µg/kg were treated under PL at the intensity of 0.52 J/cm2/pulse for different durations. The results showed that the degradation of AFB1 and AFB2 in both filter papers and rough rice followed the second-order reaction kinetic model well (R2 > 0.98). For filter paper treatment, the degradation rate was proportional to the initial concentrations of the aflatoxins and the intensities of the PL irradiation. For inoculated rough rice, after being treated with PL for 80 s, the amounts of AFB1 and AFB2 were reduced by 75.0% and 39.2%, respectively. It is concluded that the degradation of AFB1 and AFB2 with the use of PL could be accurately described using the second-order reaction kinetic model.