2.4. AfB1 Retention from Aqueous Corn Flour with 60% Methanol Extraction
Aflatoxin adsorption from aqueous corn flour dispersions was used as a more applied and more conservative measure of aflatoxin retention. Batch adsorption isotherms from aquous corn meal (6 points in triplicate with 4 blanks) were prepared with an initial concentration of 1.5 μg AfB1/mL (3 μg AfB1/g corn meal) in 2 mL aqueous dispersions containing 1 to 20 mg (0.1 to 2%) clay or 5 to 100 mg (0.5 to 10%) of activated carbon. Blanks were prepared similarly using only AfB1, corn flour, and water. The 3 μg AfB1/g corn flour that was used is comparable to highly-contaminated (3000 μg aflatoxins/kg) grain. The samples were thoroughly mixed using a vortex mixer. After overnight agitation on a reciprocating shaker, 8 mL of a 60% methanol/40% 2M NaCl extracting