Pii: S0925-5214(01)00093-x

Acetaldehyde, ethanol and non-protein bound amino acids were determined in broccoli florets (Brassica oleracea L. var. Italica cv. Marathon) stored for 7 days at 10°C in air or controlled atmospheres (0.125, 0.25, or 0.5% O2 alone or in combination with 20% CO2, or 20% CO2 in N2) followed by 2 days aeration. Floret yellowing was visible at days 7 and 9 in air. Low O2 or low O2 plus high CO2 atmospheres delayed yellowing. Acetaldehyde and ethanol concentrations increased as O2 concentrations decreased with or without 20% CO2. Aeration for 2 days generally reduced acetaldehyde and ethanol concentrations. The total free amino acid concentration increased during air-storage from 244 mol g dry weight at harvest to 573 mol g dry weight at day 9. Due to severe soft rot development in the broccoli treated with 0.125 and 0.25% O2 free amino acids were only determined in samples treated with 0.5% O2, 0.5% O2+20% CO2 and 20% CO2. Amino acid change in samples stored under 0.5% O2 were similar to those of air-stored broccoli. Storage for 7 days in the CO2-containing atmospheres resulted in an increase in non-protein amino acids and a decrease in protein amino acids, although total amino acid content remained the same. Alanine accumulated in 0.5% O2 or 20% CO2 in N2 atmospheres. The non-protein amino acid, -aminobutyrate accumulated in 20% CO2 but its concentration decreased upon aeration, and these changes were associated with similar but opposite changes in glutamate concentrations. Aspartate content also decreased in 20% CO2 and increased upon aeration. This coincided with the formation of an unidentified amino acid. In broccoli treated with high CO2 atmospheres, -decarboxylation seemed to be an important path of metabolic interconversion, however, these reaction pathways were reversible upon aeration. © 2001 Elsevier Science B.V. All rights reserved.