不同解冻处理对猪肉理化特性及微生物数量的影响

以空气解冻、4 ℃冰箱解冻、静水解冻和微波解冻4 种不同解冻方式处理猪肉，分别测定处理后猪肉的汁 液流失率、蒸煮损失率、剪切力值、色泽、pH值、总挥发性盐基氮（total volatile basic nitrogen，TVB-N）含量、 硫代巴比妥酸反应物（thiobarbituric acid reactive substance，TBARs）值、菌落总数及乳酸菌数量，研究解冻方式 对猪肉品质的影响。结果表明：静水解冻后猪肉的解冻汁液流失率（2.74%）、蒸煮损失率（16.60%）、亮度值 （57.12）、红度值（13.94）、TVB-N含量（12.95 mg/100 g）和TBARs值（0.10 mg/100 g）低于其他3 种解冻方 式，pH值接近鲜肉，菌落总数及乳酸菌数量较低，因此静水解冻对猪肉的理化性质具有较好的保持作用；4 ℃冰箱 解冻后猪肉的剪切力值（25.41 N）最低，对猪肉嫩度的保持效果较好；微波解冻猪肉的黄度值（11.06）最低；随 着肉样冻结时间的延长，解冻肉中的菌落总数与乳酸菌数量均呈波动变化趋势；肉中的微生物数量对其理化性质具 有显著或极显著影响。在4 种解冻方式中，静水解冻能更好地保持猪肉品质。

Effects of Different Thawing Methods on Pork Physicochemical Properties and Microbial Counts

The aim of this study was to investigate the effects of thawing methods on pork quality. Thawing loss, cooking loss, shear force, color, pH value, total volatile basic nitrogen (TVB-N) content, thiobarbituric acid reactive substance (TBARs) value, aerobic bacterial count and Lactobacillus count were measured after thawing by four different methods, i.e. natural air thawing, thawing at 4 ℃ in a refrigerator, still water thawing and microwave thawing. The results showed that the thawing loss, cooking loss, brightness value, redness value, TVB-N content and TBARs value of frozen pork thawed in still water were 2.74%, 16.60%, 57.12, 13.94, 12.95 mg/100 g and 0.10 mg/100 g, respectively, which were lower than those observed using other thawing methods, the pH value was close to that of fresh pork, and the aerobic bacterial count and Lactobacillus count were lower. Accordingly, the thawed pork maintained good physicochemical properties. The frozen pork thawed at 4 ℃ showed the lowest shear force (25.41 N) and maintained good tenderness. The microwave-thawed sample had the lowest yellowness value (11.06). The aerobic bacterial count and Lactobacillus count in thawed pork samples showed a fluctuating trend with freezing time. The physicochemical properties of thawed pork were significantly or highly significantly affected by microbial counts. Among the four thawing methods, still water thawing provided better maintenance of pork quality.