不同冻结方式对冻结猪肉保水性的影响机制

为探究不同冻结方式对冻结猪肉保水性的影响机制,以冷鲜肉样品为对照,对应用液浸冷冻处理和空气冷冻处理的冻结样品进行冻结损失率、解冻汁液流失率、蒸煮损失率、pH值、水分分布状态、蛋白降解等指标的测定和组织结构观察。结果表明:在冻结3 d和3个月时,液浸冷冻处理样品冻结损失率显著低于空气冷冻处理的样品(P<0.05),液浸冷冻处理样品的pH值无显著性差异(P>0.05),与冷鲜肉相比,不易流动水向结合水和自由水迁移,结合水含量显著增加(P<0.05);空气冷冻处理样品pH值显著降低(P<0.05),与冷鲜肉相比,不易流动水和结合水向自由水迁移,自由水含量极显著增加(P<0.01),液浸冷冻处理样品的肌间空隙小于空气冷冻处理样品;以上均解释了液浸冷冻处理样品在冻藏期间的保水性优于空气冷冻的原因。该研究结果对猪肉冻结工艺的优化具有一定的技术支撑作用。

Effects of Different Freezing Methods on Water-Holding Capacity of Frozen Pork

To explore the mechanism behind the effect of different freezing methods on the water-holding capacity of frozenpork,immersion-frozen and air-frozen pork were subjected to determination of freezing loss,thawing loss,cooking loss,p H,water distribution and protein degradation and their microstructure were observed.Chilled samples were considered ascontrol.Results showed that the freezing loss of 3-day and 3-month immersion-frozen samples was significantly lower thanthat of their respective air-frozen counterparts(P<0.05).The p H value of immersion-frozen samples did not significantlychange with increasing freezing time(P>0.05),and the immobilized water was transformed into bound and free water,with a significant increase being observed in the proportion of bound water(P<0.05).On the other hand,the p H value of air-frozen samples decreased significantly(P<0.05),and the immobilized water and bound water were all transformed into freewater,with a significant increase being observed in the proportion of free water(P<0.01).The intermuscular space decreased in immersion-frozen samples as compared to air-frozen samples.Overall,these results could explain why the water-holdingcapacity of immersion-frozen samples was superior to that of air-frozen samples,which will provide technical support forthe optimization of pork freezing.