Ascorbic Acid and /-carotene in Soybeans as Influenced by Maturity, Sprouting, Processing, and Storage1

Soybeans harvested at various stages of maturity and sprouted were evaluated for ascorbic acid and j3-carotene \n the fresh, cooked, canned, frozen, and stored packs. Both vitamins decreased markedly as the beans matured and in creased upon sprouting. Ascorbic acid (mg/lOOg); fresh—30, dry—2, sprouted—11. j8-carotene (mg/ lOOg); fresh—0.35, dry—0.12, sprouted—0.20. Severe ascorbic acid losses (50 to 70%) were experienced due to cooking or canning, whereas, freezing and storage losses were less (10-30%). tf-carotene retention was 80-90% in all treat ments. The large-seeded vegetable type is prefer able as a green-mature vegetable and the smaller agronomic type is more effective as sprouts. Veg etable and agronomic types were similar in ac ceptance when evaluated at either fresh green or soaked dry maturities. Despite the increasing importance of soybeans as an agronomic crop [Florida plantings increased over 5-fold in the last decade to a value of $58 million (20)], there has been relatively little emphasis upon vegetable uses. Green mature (GM) and sprouted soybeans are important forms of utilization in the orient (19). Around 45 years ago there was some wartime interest in vegetable uses resulting in useful reports on variety suita bility (22) and sprouting techniques (3). This interest in the U.S. lagged only to be renewed within the last decade when the international and national implications of soy's impressive versatili ty and nutritive quality were again recognized and home use encouraged (13, 16). The primary difficulty in utilizing GM soy beans is due to the extremely tedious hand har vesting and shelling requirements. Collins et al. (4, 5), suggested machine-harvest procedures and prototype shelling equipment to remove the tend er green seeds from the tough pod. Soybeans recommended for GM consumption are the socalled vegetable types, consisting of large-seeded varieties which are easier to hand shell and re portedly are more flavorful than the agronomic types in both the GM (22) and dry mature (DM) states (7). Home methods of sprouting have been developed to further extend soybeans utility (3, 8). The high protein content and quality of soybeans are the most valuable features of this crop and the reason for the present viable inter national trade. Protein content in GM, DM or sprouted soybeans is about 40% on a dry weight basis, possessing about 80% of the nutritive quality of casein (18). Both GM and sprouted soybeans are reported to have modest to markedly enhanced vitamin contents relative to the DM soy bean (17, 8). Some of these data have been de veloped over many years and are at times con flicting, particularly regarding processing and storage effects. Nutrient retention in processed 'Verde' and 'Early Green' Varieties (hand harvested a OPTIMUM MATURITY) ► Roller shelled without heat ►Steamed 1,5 min, spray-cooled, roller shelled