54I-18 |
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A. D. PRUDENTE, JR. and J. M. King. Dept. of Food Science, LSU AgCenter, 111 Food Science Bldg., Louisiana State Univ., Baton Rouge, LA 70803-4200 Chemical analysis has shown that ozonation can effectively reduce aflatoxin levels in contaminated corn. Evaluation of extracts from sequential fractionation and digestion procedures showed that some isolates exhibited mutagenic potentials in the Ames assay. This result suggested the presence of residual aflatoxins and/or mutagenic reaction products formed by the ozonation process. The objective of this study was to investigate the distribution of aflatoxins in corn after a series of extraction, partition, and digestion procedures by TLC. Corn samples included untreated clean corn, ozone-treated clean corn, untreated contaminated corn, and ozone-treated contaminated corn. Ozone treatments were done with 12 to 14 wt% ozone at a flow rate of 2L per minute for 96 hr. Extracts isolated through sequential fractionation and digestion procedures were subjected to TLC. Extract was dissolved with methylene chloride and 10-µL was spotted on a 10 x 20 cm silica gel plate. Ten-µL of mixed aflatoxins was used as external standard. The plate was first developed with petroleum ether and then with ether-methanol-water (96/3/1). The plate was examined for fluorescent spots having Rf's close to those of the reference standards. Aflatoxin B1 and B2 were present in methylene chloride, methanol, acetone, pronase soluble solid, and pronase organic fractions from untreated contaminated corn. Aflatoxin B1 and B2 were also observed in fractions from ozone-treated contaminated corn, but to a lesser extent. No aflatoxin was observed in extracts from untreated and ozone-treated clean corns. No aflatoxin was also observed in hexane extracts from all samples. The presence and absence of aflatoxins in the extracts supported the results of the Ames mutagenicity assay from previous work. Results showed a positive correlation between the presence of aflatoxin in the extract and the mutagenic response of tester strains in the Ames assay.
Session 54I, Toxicology & Safety Evaluation: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |