Development of oxidized odor and volatile aldehydes in fermented cucumber tissue exposed to oxygen

Changes in volatile compounds in fermented cucumber tissue during exposure to oxygen were investigated by purge and trap sampling, followed by GC-MS. Hexanal and a series of trans unsaturated aldehydes, (E)-2-pentenal, (E)-2-hexenal, (E)-2-heptenal, and (E)-2-octenal, increased in fermented cucumber slurries exposed to oxygen. Sensory evaluation of oxidized odor was correlated with the increase in aldehyde concentrations. Other identified volatile components present after fermentation did not show major changes during exposure to oxygen. There was no decrease in the formation of aldehydes in fermented cucumber samples that were heated to inactivate enzymes before exposure to oxygen. These results indicated that the formation of aldehydes in oxygen was due to nonenzymatic reactions.