屠宰应激对宰后猪肉保水性的影响

Effect of Slaughter Stress on Post-slaughter Pork Water-holding Capacity

本文研究了电击晕和二氧化碳致晕对杜大长三元杂交猪和三门峡黑猪的应激效应及宰后肌肉保水性的影响。结果表明:与电击晕相比,二氧化碳致晕使得杜长大三元杂交猪和三门峡黑猪血液中的乳酸(LAC)、乳酸脱氢酶(LDH)、肌酸激酶(CK)、肌酐(CRE)、皮质醇(COR)含量显著降低(P<0.05);且杜长大三元杂交猪和三门峡黑猪宰后p H45min值较高,差异显著(P<0.05),宰后24 h汁液损失率(降低1.17%和0.59%)、蒸煮损失率(降低3.09%和3.56%)及解冻损失率(降低0.55%和0.29%)显著降低(P<0.05);剪切力显著降低0.71 kg及0.66 kg(P<0.05)。此外,杜长大三元杂交猪的抗应激能力较差,其宰后肌肉保水性显著低于三门峡黑猪(P<0.05)。LF-NMR研究表明,二氧化碳致晕能够显著降低解冻后肌肉中的自由水含量(降低32.24%和28.92%),抑制了不易流动水向自由水的"态变"。因此,在实际生产中采用二氧化碳致晕能降低生猪屠宰应激,提高肌肉保水性。

The influences of electric and carbon dioxide stunning methods on ante-mortem stress and its effect on water-holding capacity of post-slaughter muscle in Duroc-Landrace-Yorkshire(with halothane genotype NN) and Sanmenxia black pigs(without halothane gene) were studied. The results showed that, compared with electric stunning, carbon dioxide stunning could significantly lower lactate(LAC), lactate dehydrogenase(LDH), creatine kinase(CK), creatinine(CRE), and cortisol(COR) content(P < 0.05) in the blood of both Duroc-Landrace-Yorkshire and Sanmenxia black pigs. The p H value measured at 45 min post-mortem(p H45min) in the longissimus muscle of pigs stunned by carbon dioxide was significantly higher(P < 0.05) than that of pigs stunned electrically. Carbon dioxide stunning significantly reduced values of muscle drip loss rate(reduced by 1.17% and 0.59%), cooking loss rate(reduced by 3.09% and 3.56%), and thawing loss rate(reduced by 0.55% and 0.29%) at 24 h post-mortem as well as shear forces(reduced by 0.71 and 0.66 kg) in the longissimus muscle of Duroc-Landrace-Yorkshire and Sanmenxia black pigs, respectively(P < 0.05). The results of low-field nuclear magnetic resonance technique(LF-NMR) indicated that carbon dioxide stunning significantly reduced the free water content(reduced by 32.24% and 28.92% for Duroc-Landrace-Yorkshire and Sanmenxia black pigs, respectively), and inhibited the transformation from immobilized to free water(state change). Thus, carbon dioxide stunning reduces the stress effect of live pigs and improves muscle water-holding capacity during pig slaughter.