不同冻存时间对猪肌内脂肪含量及其与生产性状相关性的影响

Effects of different freezing time on the determination of intramuscular fat content and its correlation with production traits in pigs

[目的]本文旨在探究不同冷冻时间对猪肌内脂肪(intramuscular fat,IMF)含量的影响并分析IMF含量和其他生产性状的相关性。[方法]从299头杜洛克×(长白×大白)三元商品猪群中随机挑选52头作为试验对象,测定屠宰前活体重、屠宰后胴体重以及相关肉质性状;采集倒数第3~4肋骨间的背最长肌,采用索氏抽提法分别测定0 d鲜肉样、-80℃超低温冻存90和180 d肉样的IMF含量。对3个不同时间点测定的IMF含量进行相关性与差异显著性分析,并对3个不同时间点的IMF含量与测定的生产性状的相关性进行比较分析。[结果]0 d与冻存90 d的IMF含量呈极极显著相关(r=0.75),2个时间点测定的平均IMF含量不存在显著差异(P>0.05),但与0 d相比,冻存90 d的平均IMF含量呈上升趋势;0 d与冻存180 d的IMF含量呈显著相关(r=0.29),但与0 d相比,冻存180 d测定的平均IMF含量极显著升高(P<0.01)。性状相关分析结果显示,0 d和90 d的IMF含量与屠宰前活体重和胴体重呈极极显著相关(P<0.001),而180 d的IMF含量仅与胴体重呈极极显著相关(P<0.001),而且不同冻存时间对IMF含量与肉质性状的相关性产生不同程度的影响。[结论]肉样在-80℃冻存会增加IMF含量,但冻存90 d对IMF含量不会产生显著影响,而冻存180 d会极显著影响IMF含量。另外,低温冷冻对测定的IMF含量与生产性状的相关性产生不同程度的影响。本研究结果可为屠宰后肌肉块IMF含量测定的标准化以及行业标准的制定提供有价值的参考。

[Objectives]The paper aimed to explore the effect of different freezing time on the intramuscular fat(IMF)content in pigs and to analyze the correlation between intramuscular fat content and other production traits. [Methods]52 experimental pigs were randomly selected from 299 Duroc×(Landrace×Large)commercial pigs. The live body weight before slaughter, carcass weight after slaughter, as well as related carcass and meat quality traits were measured. The longissimus dorsi muscle between the last 3-4 ribs was collected, the contents of IMF in 0 d fresh meat samples, 90 d and 180 d frozen at-80 ℃ meat samples were measured by soxhlet extraction method. On this basis, the correlation and difference significance of IMF content was measured at three different time points were analyzed, and the correlation between the IMF content measured at three different time points and the measured production traits were compared and analyzed. [Results]The results showed that the IMF content at 0 d and 90 d after freezing was significantly correlated(r=0.75),and there was no significant difference between the IMF content measured at two time points(P>0.05);but compared with 0 d, the average IMF content at 90 d after freezing showed an upward trend. The IMF content at 0 d was significantly correlated with that at 180 d of freezing(r=0.29),but the average IMF content measured at 180 d of freezing was significantly higher than that at 0 d(P<0.01). The results of trait correlation analysis showed that the IMF content measured at 0 and 90 d was significantly correlated with live body weight and carcass weight before slaughter(P<0.001),while the IMF content at 180 d was only significantly correlated with carcass weight(P<0.001),and different freezing time had different effects on correlation between IMF content and related meat quality traits. [Conclusions]Freezing meat samples at-80 ℃ would increase the determination results of IMF content, but freezing for 90 d would not have a significant impact on IMF content, while freezing for 180 d would significantly affect the determination results of IMF content. In addition, low temperature freezing had different effects on the correlation between the measured intramuscular fat content and production traits. The results of this study can provide valuable reference for the standardization of the determination of intramuscular fat content of slaughtered muscle blocks and the formulation of industry standards.