Effects of varied substrates on aflatoxin production by A. parasiticus

Sterilized and nonsterilized wheat kernels, soybean seeds, sesame seeds, peanut and faba bean were infected by A. parasiticus. The chemical composition, aflatoxin content and fatty acid patterns of the seeds were determined. The aflatoxins B1, B2, G1 and G2 were detected, and the amounts of the unsaturated toxins (B1 and G1) were greater than the respective dihydro derivatives (B2 and G2). Sterilized seeds infected by the fungus contained greater amounts of aflatoxins than those infected without previous sterilization. the highest and lowest toxicity indices were recorded for sterilized wheat and soybeans, respectively. Sesame, peanut and soybean exhibited intermediate toxicity indices. The toxicity of the aflatoxins produced was related significantly in every instance to the carbohydrate and lipid:protein ratio, and not to the polyunsaturated fatty acids of the seeds. © 1986 The American Oil Chemists' Society.