Comparison of key aroma components between soymilks prepared by cold and hot grinding methods

Aroma components of soymilks made by two procedures, hot grind and cold grind, were isolated by solvent-assisted flavor evaporation (SAFE) and analyzed by gas chromatographyolfactometery (GCO) and GC-mass spectrometry (GC-MS). Hexanal, (E,E)-2,4-nonadienal, (E,Z)-2,4-decadienal, 1-octen-3-ol, (E)-2-nonenal and (E,E)-2,4-decadienal were identified as key aroma-active compounds in both hot grind and cold grind soymilks. With the exception of some thermally generated volatiles (e.g., 2-acetyl-1-pyrroline), the odor-activity values (OAVs) for most of the potent soymilk odorants were higher in the cold grind soymilk. The greater abundance of lipid-derived volatiles in the cold grind soymilk indicated the effectiveness of the hot grind process in reducing lipoxygenase activity during soymilk manufacture. However, the hot grind processing could not prevent the formation of all lipid-derived volatiles, therefore, other processing strategies are necessary to eliminate soymilk off-flavors.