Effect of Ultra-high-pressure Sterilization on Flavor and Physicochemical Properties of Low-salt Sliced Bacon

The effect of ultra-high pressure (UHP) sterilization technology on the quality of low-salt sliced bacon was investigated by treating samples under 200, 400 and 600 MPa for 10 min at 22 ℃. The samples were stored at 4 ℃ and the unsterilized group was used as the control group. The physicochemical indexes, flavor substances and the total number of colonies of the samples were determined when the storage time was 0, 60, 120 and 180 days, respectively. The results indicated that the moisture content, nitrite content, hardness, a* value, b* value, and total bacterial counts of the low-salt sliced bacon decreased, while the pH value, POV value, L* value, elasticity, recovery, and cohesiveness increased after ultra-high pressure treatment. During the storage process, ultra-high pressure conditions enhanced the water-holding capacity of the bacon, slowed down lipid oxidation, and effectively inhibited the microbial growth. At 180 days, the moisture content, L* value, a* value, elasticity, and cohesiveness of the ultra-high pressure group were higher than those of the control group, while the pH value, nitrite content, hardness, and total bacterial counts were lower than those of the control group. The experimental results of gas chromatography-mass spectrometry (GC-MS) and electronic nose showed that the flavor components of ultra-high pressure group were similar to those of the control group, and then the difference of the content was small. Moreover, UHP treatment promoted and protected the flavor formation of bacon. However, excessive pressure (600 MPa) not only aggravated lipid oxidation, but also affected the color and texture of the bacon, thus affecting the sensory score of bacon. Overall, the optimal treatment pressure was determined to be 400 MPa in this study.