反复冻融对调理鸡肉骨肉相连品质的影响

Effects of freeze-thaw cycle on quality of chicken flesh and bones

为了研究反复冻融对骨肉相连品质特性的影响,将调理鸡肉骨肉相连放置于-18℃的冰箱中冻藏5 d,在(5±1)℃条件下解冻后再冻藏,采用低场核磁共振(Nuclear magnetic resonance,NMR)CPMG探究其水分含量的分布状态及变化,探究其品质变化.结果表明,随着反复冻融次数的增加,骨肉相连感官得分和解冻时间均逐渐减小,蒸煮损失增加,T22逐渐减小,品质下降,结合水含量(A1)和不易流动水含量(A2)处于动态平衡的状态.T22与感官特性、解冻时间以及冻融次数呈显著相关,相关系数分别为0.731,0.722,-0.731;A1和A2与蒸煮损失呈极显著相关,相关系数分别为-0.693,0.621;NMR图像由亮到暗,水分由内向外迁移.因此,NMR可用于反复冻融骨肉相连品质的在线评价,且反复冻融易引起骨肉相连品质劣变,应尽可能防止发生.

This study was designed to explore the effect of the freeze-thaw cycle on the physiochemical quality of chicken flesh and bones. The flesh and bones were first placed in the fridge at - 18 ℃ for 5 d, then were thawed completely in the thermostatic culture box at （5 ±1 ） ℃ ,and finally its physio- chemical index was measured and relaxometry of water in flesh and bones during freeze-thaw cycles was characterized using low-field nuclear magnetic resonance （NMR）. The results show that with the in- creasing of freeze-thawing cycles, the thawing time and sensory score gradually decreased; the purge loss increased ; The transverse relaxation time（T22） of NMR significantly decreased; the physiochemical quality and the quality properties of flesh and bones were declined and seriously damaged. At the same time immobilized water （A1） and hydration water （A2） were in the dynamic balance state; T22 with sensory characteristics, thawing time and freeze-thaw number had significant correlation, and the correlation coefficient was 0. 731, 0. 722, and - 0. 731 respectively; A1 and A2 with cooking losses were very significantly related, and the correlation coefficient was - 0. 693 and 0. 621 respectively; MRI results showed that image changed from light to dark, the water-retaining property of flesh and bones dropped, with water moving from inside to outside. Therefore, NMR can be used in the process of flesh and bones circulation linked the quality evaluation online, and repeated freeze-thaw could easily cause the quality deterioration, and should be prevented.