Effects of low-level gamma irradiation on the characteristics of fermented pork sausage during storage

摘要

The effect of gamma irradiation (0.5,1, 2, and 4 kGy) on the quality of vacuum-packaged dry fermented sausages during refrigerated storage was evaluated. At Day O of irradiation, the pH, redness (CIE a*), yellowness (CIE b*), 2-thiobarbituric acid-reactive substances (TBARS) and volatile basic nitrogen (VBN) values of samples irradiated at 2 and 4 kGy were higher (p < 0.05), but the CIE L* values (lightness) were lower than those of the non-irradiated control (p < 0.05). At < 1 kGy irradiation, however, the pH, CIE L*, CIE a* and CIE b*-value of samples were not significantly influenced by irradiation. The CIE a*, and CIE b*-values of samples irradiated at 2 and 4 kGy decreased with the increase of storage time. The VBN, TBARS, and CIE L*-values of samples irradiated at 4 kGy were not changed significantly during refrigerated storage for 90 days (p > 0.05). The total plate counts (TPC) and lactic acid bacteria (LAB) in the samples irradiated at 4 kGy were significantly lower (p < 0.01) than those with lower irradiation doses. At the end of storage, the TPC, coliform, and LAB in the samples were not increased after irradiation at 1, 0.5 and 1 kGy, respectively. TPC and LAB were not detected in samples irradiated at 4 kGy at Day 90. In addition, no coliform bacteria were found in samples irradiated at 1 kGy during refrigerated storage. Sensory evaluation indicated that the rancid flavor of samples irradiated at 4 kGy was significantly higher, but aroma and taste scores were lower than those of the control at Day 3 of storage. Irradiation of dry fermented sausages at 2 kGy was the best conditions to prolong the shelf-life and decrease the rancid flavor without significant quality deterioration.