冻融循环处理对皱纹盘鲍质地的影响

为探究冻藏温度的波动对鲍鱼质地的影响,选取商品速冻鲍鱼的贝柱部分作为研究对象,分析了5次冻融循环处理对肌肉的质构、保水性、场核磁共振T₂弛豫时间及蛋白氧化的影响。结果表明：鲍鱼肌肉质构的硬度、弹性和咀嚼性指标随冻融次数的增多而显著降低(P < 0.05),5次循环后分别降至原来的11.21、3.03和10.04%,而剪切力相反,发生显著升高；鲍鱼肌肉持水性的解冻损失、离心损失和蒸煮损失发生了显著升高(P < 0.05),分别从2.28、16.09和38.51%升高至10.50、28.53和43.67%；鲍鱼肌肉水分分布中结合水几乎不受影响,而不易流动水与自由水的弛豫时间T₂₂与T₂₃明显增大,其对应的峰面积比例P₂₂显著上升和P₂₃显著降低(P < 0.05)；鲍鱼肌肉蛋白结构及功能的表面疏水性先上升后降低,羰基含量显著降低而活性巯基含量显著升高(P < 0.05)。这些研究表明,冻融循环会对鲍鱼的肌肉质地造成破坏,致使其质地品质劣变,商品价值降低,最终影响消费者的可接受性。

Effect of freeze-thaw cycles on texture of Haliotis discus hanai muscle

In order to explore the effect of temperature fluctuations on the texture of shellfish muscle, the commercial quick-frozen abalone was selected as the research object, and the texture, water-holding, field nuclear magnetic resonance and protein oxidation of 5 times freeze-thaw cycles were determined. The results showed that the stiffness, elasticity, and chewiness of the muscles decreased significantly with the increase of freeze-thaw times (P <0.05), which decreased to 11.21, 3.03, and 10.04% respectively after 5 cycles. On the contrary, the shear force increased significantly (P <0.05). The water retention studies found that the thawing loss, and cooking loss of muscles increased significantly (P < 0.05) from 2.28, 16.09and 38.51% to 10.50, 28.53 and 43.67%, respectively. LF-NMR showed that the bound water was hardly affected during the freeze-thaw cycles and the relaxation times T₂₂ and T₂₃ of the immobilized water and free water shifted significantly to the right, and the corresponding peak area ratio P₂₂significantly increased and P₂₃significantly decreased (P <0.05). Changes in protein structure and function have an adverse effect on muscle texture. It was found that hydrophobicity increased first and then decreased, and carbonyl content decreased significantly while active sulfhydryl content increased significantly (P < 0.05) during the freeze-thaw cycles. The study has shown that the freeze-thaw cycle can damage the muscle texture of abalone, causing poor texture and lower the value of the commodity, eventually affecting consumer acceptability.