Active packaging of UHT milk to prevent the development of stale flavour during storage

Indirectly processed UHT milk was packaged in Intasept (TM) aseptic pouches with (treatment) or without (control) oxygen-scavenging film and stored for 14 weeks at 26 +/- 0.3 degrees C. Samples were analysed at 0, 4, 8 and 14 weeks for dissolved oxygen, stale flavour volatiles (methyl ketones and aldehydes) and free fatty acids. Discriminative subjective analysis of odour by a consumer panel was also conducted. The oxygen-scavenging film was shown to significantly (p < 0.05) reduce dissolved oxygen content by 23-28% during storage. Significant reductions of 23-41% were also observed for some stale flavour volatiles, including three methyl ketones and two aldehydes. Free fatty acid levels remained far below threshold values, indicating that lipolytic rancidity would not interfere with the subjective analysis. However, the consumer panel failed to detect a significant difference in odour between the treatment and control samples. Copyright (c) 2006 John Wiley & Sons, Ltd