The formation of aliphatic aldehydes and alcohols, primarily from unsaturated fatty acids with the participation of lipoxygenase, hemoproteins, alcohol dehydrogenase, and esterase, is briefly reviewed with special regard to plant foods. The controlling or avoiding of aldehyde formation in food systems by the use of alcohol dehydrogenase and of certain sugar-aminc acid reaction products was studied, by use of a gas Chromatographic technique.