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 correl ated with the increase in aldehyde concentrations. Other identified volatil e components present after fermentation did not show major changes during e xposure to oxygen. There was no decrease in the formation of aldehydes in f ermented cucumber samples that were heated to inactivate enzymes before exp osure to oxygen. These results indicated that the formation of aldehydes in oxygen was due to nonenzymatic reactions.