微冻及冰温结合气调包装对羊肉的保鲜效果

比较微冻、冰温结合气调包装对羊肉品质的影响,确定适合于羊肉保鲜新方法。以羊肉为原料,比较-3℃微冻、-1℃冰温气调包装(75%O2+25%CO2)与两个温度条件下普通包装的羊肉在贮藏过程中p H值、挥发性盐基氮(total volatile base-nitrogen,TVB-N)值、微生物菌落总数、汁液流失率等品质等指标的变化。结果表明,与-1℃冰温相比,-3℃微冻能很好地控制羊肉微生物菌落总数和TVB-N值,延缓p H值的升高,但汁液流失率为-1℃冰温贮藏的4~5倍。相同温度条件下,与普通包装相比,气调包装能使羊肉保持良好的色泽,抑制微生物菌落总数的增加,延长羊肉的保鲜期10 d。综合来看,-3℃微冻气调包装对于宰后羊肉品质的保持效果最好,可以使羊肉有效保鲜时间达40 d,此时羊肉微生物菌落总数为5.79(lg(CFU/g)),符合国家安全鲜肉标准(≤6(lg(CFU/g));TVB-N值为14.47 mg/100 g,符合国家一级鲜肉的标准(≤15 mg/100 g);p H值为5.84,符合国家一级鲜肉的标准(p H 5.18~6.12)。

Comparative Effects of Superchilling and Ice-Temperature Combined with Modified Atmosphere Packaging on Mutton Quality during Storage

In order to determine a more suitable method for mutton preservation, the effects of superchilling and icetemperature combined with modified atmosphere packaging (MAP) were comparatively explored on mutton quality. This experiment examined changes in pH, total volatile base-nitrogen (TVB-N), total bacterial count (TBC) and drip loss rate of mutton subjected to ordinary packaging and modified atmosphere packaging (MAP, 75% O2 + 25% CO2) during storage under superchilling (?3 ℃) and ice-temperature (?1 ℃) conditions. The results showed that compared with ice temperature storage, superchilling allowed better control of TBC and TVB-N in MAP packaged mutton and delayed the increase in pH, but it resulted in a four–five-fold increase in drip loss rate. At the same storage temperature, MAP treatment maintained mutton color better, inhibited bacterial growth and prolonged the shelf life by 10 days during storage compared with ordinary packaging. Taken together, the quality of MAP packaged mutton was maintained best, for up to 40 days, during superchilling storage. After this storage period, TBC was 5.79 (lg(CFU/g)), which was within the range of the national standard (≤6 (lg(CFU/g))), TVB-N value was 14.47 mg/100 g, which met the requirement for first-grade fresh meat according to the national standard (≤15 mg/100 g), and pH was 5.84, which met the requirement for first-grade fresh meat according to National Standard (pH 5.18-6.12).