Indexed on: 01 Oct '77Published on: 01 Oct '77Published in: Journal of the American Oil Chemists' Society
Legumes contain unsaturated lipids that are susceptible to oxidative deterioration. Enzymic and non-enzymic deterioration of these lipids results in the development of off-flavors. The primary objective of this review is to summarize what is currently known about lipid-derived flavors of soybeans and underblanched pea seeds(Pisum sativum). Identifying the numerous volatile compounds arising from breakdown of lipid hydroperoxides coupled with organoleptic evaluation defines the flavor problem. Major contributors to the green-beaniness of soybeans were found to be 3-cis-hexenal, 2-pentyl furan, and ethyl vinyl ketone. Oxidized phosphatidylchohnes cause some of the bitter taste. The interaction of lipid breakdown products with proteins, carbohydrates, and other constituents can affect flavor characteristics and also increase the problems of their removal from soy protein products. To prepare bland products, it will be necessary to develop processes that effectively remove bound flavor components and prevent formation of derived flavors. Solvent systems based on alcohol have been used to extract flavor principles from soybeans; aqueous alcohol treatment of the intact seed or blanching with hot water or steam inhibits formation of off-flavors in peas and soybeans. A new approach involving infusion of antioxidants into the intact seed to control lipid deterioration during processing and storage is proposed to minimize flavor formation without subsequent undesirable changes in protein which occur with alcohol treatments.