FULL FAT SOY FLOUR Full fat soy flours contain only 40 % protein. For use as a raw material for animal feed, they need to be heat treated to deactivate the enzyme lipoxygenase (this to avoid formation of rancidity during storage) and to destroy the anti-nutritional factors that are naturally present in soybeans. For other applications, such as bread baking, enzyme-active full fat soy flour is preferred.