Studies on Flavor Components in Soybean

Volatile neutral fraction of flavor components in raw soybean was investigated. Ground raw soybean was packed in a glass column, warmed at about 50°C by a water-jacket column, and swept with nitrogen gas. Volatile materials swept out were trapped in bottles dipped in ice-water, solid carbon dioxide-acetone and liquid nitrogen in this order, and were submitted to gas chromatography. The peaks corresponding to basic and carbonyl compounds were eliminated by treating the original volatile materials with 2, 4-dinitro-phenylhydrazine in phosphoric acid, and the residual peaks were compared with authentic alcohols and esters. Methanol, ethanol, 2-pentanol, isopentanol, n-pentanol, n-hexanol and n-heptanol were found as alcohols, and n-pentanol acetate was found as an ester. Other methods of identification of alcohols were carried out by introducing these into 3, 5-dinitrobenzoate derivatives, which were investigated by thin-layer and paper chromatographies. Isopentanol, n-hexanol and n-heptanol were considered to be important factors among the volatile neutral components, which gave green bean-like odor to soybean.