SOLID-PHASE EXTRACTION FOR GC ANALYSIS OF BEANY FLAVORS IN SOYMILK

An octadecyl sorbent column was selected for solid phase extraction of volatile components of soymilk. The volatiles thus adsorbed were elut ed with a mixture of hexane and diethyl ether (3:1 v/v) and then appli ed directly to GC column. The detection limit of the method was 0.1 pp m for both hexanal and hexanol. Total content of these two compounds i n soymilk was linearly correlated to the lipoxygenase activity in soyb eans. Data points on principal component similarity (PCS) scattergrams for soymilk samples were grouped toward two directions depending on t he grit size of ground beans heated by microwave. Sensory panels detec ted beany flavour in these samples but without distinction between the se two types of GC patterns as classified on the PCS scattergram. Prin cipal components 1 (PCI) and 2 (PC2) had high loadings of pentanol and hexanal and hexanol and hexanal, respectively. Pentanol was produced upon heating finely ground soybeans. (C) 1998 Canadian Institute of Fo od Science and Technology. Published by Elsevier Science Ltd. All righ ts reserved.