ODORANTS OF EXTRUSION PRODUCTS OF OAT MEAL - CHANGES DURING STORAGE

Aroma extract dilution analysis of a fresh extrusion product (EP) of oat meal showed 25 odorants of which hexanal (I), octanal, trans-2,3-epoxyoctanal (II), (E,E)-2,4-nonadienal (III), (E,E)-2,4-decadienal (IV), trans-4,5-epoxy-(E)-2-decenal (V), 4-hydroxy-2-nonenoic acid lactone (VI) and vanillin (VII) appeared with high FD factors. Compounds I to VI and caproic acid (VIII), which increased during storage of EP, were quantified by an isotope dilution assay. Soaking the EP in water liberated especially VII from starch inclusion complexes; its concentration (mg/kg) which was determined after methylene chloride extraction increased from 0.09 to 6.7. During storage of EP in closed bags at 22-degrees-C the levels (mg/kg) of I and VIII increased, causing a rancid off-flavour: 0 d, 0.5 I, 1.9 VIII; 35 d, 1.2 I, 10.4 VIII; 1 year 9.6 I, 11.3 VIII.