1-Octen-3-ol Is Formed from Its Glycoside during Processing of Soybean [Glycine max (L.) Merr.] Seeds

Soaking and maceration of dry soybean seeds induce the formation of aliphatic volatile compounds that impact the flavor properties of food products prepared from soybean. Most aliphatic volatile compounds are formed through oxygenation of unsaturated fatty acids by lipoxygenases; however, lipoxygenases are not responsible for the formation of 1-octen-3-ol. 1-Octen-3-ol in soybean products is in general an off-flavor compound; thus, a procedure to manage its formation is required. In this study, we show that the formation of 1-octen-3-ol after hydration of soybean seed powder is independent of oxygen, suggesting that 1-octen-3-ol is not formed de novo from unsaturated fatty acids but instead from its derivative. When crude methanol extract of soybean seeds was reacted with beta-glycosidases, 1-octen-3-ol was rather liberated from its glycoside. We purified the parent glycoside from soybean seeds and confirmed it as (R)-1-octen-3-yl beta-primeveroside [(R)-1-octen-3-yl 6-O-beta-D-xylopyranosyl-beta-D-glucopyranoside]. Green immature soybean fruits (pericarp and seeds) contain a high amount of 1-octen-3-yl beta-primeveroside. Its amount decreases after hydration of dry soybean powder. The results indicate that management of 1-octen-3-ol levels in soybean products requires a different strategy than that applied to off-flavor compounds formed de novo.