44G-19 |
Degradation of aflatoxins in the presence of nucleophiles |
F. K. SAALIA, Department of Food Science and Technology, University of Georgia, Griffin, GA 30223 and R. D. Phillips. Attempts to detoxify aflatoxins in agricultural produce by chemical means have often been flawed by possible toxicological concerns about the reagents. A successful use of amino acids as nucleophiles in this effort would ameliorate such concerns, and improve the nutritional value of the product. The objective was to compare the relative efficacies of lysine, glycine and methylamine in model buffer solutions. A factorial design consisting of 0.1M phosphate buffer pH (7,8,9), heating temperature (100, 125, 150) and nucleophile (control, lysine, glycine and methylamine) was used. The degradation kinetics of aflatoxins in buffer solutions for each of the nucleophiles was followed at 150°C. 4mL of each buffer was spiked with a mixed aflatoxin standard to contain 200ug/L of B1 and G1 and 60ug/L of B2 and G2. The samples were heated in a glycerol bath, and after each heating protocol, they were rapidly cooled on ice, and residual aflatoxins determined using HPLC procedures with florescence detection. The relative efficacies of the nucleophiles in a heterogeneous system were also compared by adding calcium chloride (0.1%) to the buffer solutions. The efficacies of the nucleophiles to degrade aflatoxins depended on the pH of the buffer solutions, and this was impacted by their respective pKas. At pH9, the degradation rate constants (k) for Lysine, glycine and methylamine at 150°C were 0.11, 0.09 and 0.08 min-1 respectively. The presence of calcium chloride seemed to protect against the degradation of aflatoxins, but adding lysine especially at pH9 effected significant aflatoxin degradation at 150°C. Methylamine is already a confirmed efficacious reagent in the decontamination of aflatoxins. These findings show a potential use of lysine, an essential amino acid, in the decontamination of peanuts and other produce.
Session 44G, Toxicology & Safety Evaluation
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