Surface Lipids of Seeds Support Both Aspergillus Parasiticus Growth and Aflatoxin Production

Abstract

Seed surface lipids (SSL) play a key role in supporting aflatoxin (AFT) output in oily and starchy seeds following infection with Aspergillus parasiticus. On oily seeds, fungal growth and AFT production occur when the levels of SSL are higher than 0.15% of total oil content of seeds, with a ratio between triglycerides and free fatty acids (TG/FFA) of SSL > 1. If FFA prevail over TG, growth can be inhibited because of the toxicity towards Aspergillus of unsaturated FFA of SSL. Defatted meals of sunflower seeds support a reduced AFT biosynthesis. On starchy seeds, A. parasiticus proliferates in the germ region, the area richest in lipids.