Formation of volatile sulfur compounds in broccoli stored under anaerobic condition.

摘要

The development of an off-flavour in anaerobically stored broccoli was studied by sealing cv. Haitsu heads in a 100-鎚-thick polyethylene film and storing them at 20鳦 for 4 days. O2 and CO2 concentrations in the package were <0.5% and >20%, respectively, within 8 h of storage; undesirable odours developed rapidly under these anaerobic conditions. Ethanol, acetaldehyde, methanethiol and dimethyl disulfide were identified as the volatile compounds in the headspace of the anaerobic packages. Volatilesulfur compounds, such as methanethiol and dimethyl disulfide, were the main contributors to off-odours. When the activity of C-S lyase, a key enzyme for the formation of volatile sulfur compounds, was measured, no significant changes were observed in activity between anaerobically packaged and non-packaged broccoli during storage. Electrolyte leakage from anaerobically packaged broccoli increased to a greater extent than that of non-packaged broccoli during storage. In addition, the level of free fatty acids in the microsomal membrane was higher in anaerobically packaged broccoli than in the non-packaged broccoli. These results suggest that, under anaerobic conditions, volatile sulfur compounds are formed by the deterioration of cellular membrane lipids and loss of intracellular compartmentation, allowing enzyme-substrate reactions to proceed.