Abstract: In order to understand the effect of ultra-high pressure (UHP) treatment on the shelf-life, quality and nutritional index of low-temperature smoked ham, the slices of vacuum-packaged smoked ham were subjected to UHP (400 and 600 MPa) treatments at 22 ℃ for 10 min prior to storage at 4 ℃. Total counts of spoilage microorganisms in UHP-treated and control hams were determined after 0, 1, 30 days and 90 days of storage. In addition, TBARS and free fatty acids were assayed and sensory analysis was performed. The results indicated that UHP treatment could effectively inactivate Enterobacteriaceae, Brochothrix thermosphacta, Pseudomonads, moulds and yeasts in smoked ham. Some lactic acid bacteria were the final dominant spoilage bacteria in smoked ham and revealed strong resistance to high-pressure treatment. The content of saturated fatty acids slightly increased, but the content of unsaturated fatty acids slightly decreased after UHP treatments. The changes of saturated and unsaturated fatty acids are pressure-dependent. At the beginning of cold storage, no change of TBARS value in smoked ham with and without high-pressure treatment was observed. However, at the late storage period, UHP-treated ham revealed increased TBSRS value. Therefore, UHP treatment can effectively extend the shelf-life of low-temperature smoked ham, and will not result in obvious changes of free fatty acids, color and lipid oxidation in smoked ham during storage 4 ℃, thereby better maintaining free fatty acid composition as well as original product quality and taste.

Key words: ultra-high pressure treatment, smoked ham, nutritional quality, shelf-life