静电场辅助冻结-解冻对肌肉保水性及蛋白理化特性的影响

以牛背最长肌（Longissmus dorsi）为研究对象，探讨静电场辅助冻结-解冻、自然冻结-解冻（对照组）、 自然冻结-静电场辅助解冻、静电场辅助冻结-自然解冻4 个处理对肌肉保水性及蛋白理化特性的影响，为冷冻肉 品质控制技术开发提供理论依据。采用差示扫描量热、核磁共振质子成像等技术，对比分析了冻结-解冻速率、解 冻汁液流失、蛋白表面疏水性、热稳定性、水分迁移等指标。结果表明：静电场辅助冻结-解冻实验组牛肉冻结、 解冻时间较对照组分别缩短16.290、8.920 h；通过最大冰晶生成带用时较对照组缩短3.41 h；解冻汁液流失率显著 低于对照组（P＜0.05），为4.19%；冻结蛋白质表面疏水性显著降低，为16.16 μg，解冻后显著升高，为9.45 μg （P＜0.05）；蛋白质变性程度显著低于对照组（P＜0.05），变性温度分别为55.130、63.940、78.350 ℃。静电场 辅助冻结-解冻可有效提高牛肉冻结-解冻速率，降低肌原纤维蛋白变性程度，减少解冻汁液损失。

Effect of Electrostatic Field-Assisted Freezing-Thawing on Water-Holding Capacity and Physicochemical Characteristics of Beef Muscle Proteins

In order to provide a theoretical basis for the quality control of beef muscle during freezing-thawing process, the effect of electrostatic field-assisted freezing and thawing on the water-holding capacity and physicochemical characteristics of myofibrillar proteins from beef Longissimus dorsi muscle was investigated. Four different freezing-thawing processes including electrostatic field-assisted freezing and thawing (EFF-EFT), conventional freezing and thawing (control), conventional freezing and electrostatic field-assisted thawing, and electrostatic field-assisted freezing and conventional thawing were used. The thermal stability of myofibrillar proteins and water migration in beef muscle during thawing process were measured by different scanning calorimetry and proton nuclear magnetic resonance, respectively. The surface hydrophobicity, freezing and thawing rate, and thawing loss were also measured. Compared to the control, the freezing and thawing time of muscles in the EFF-EFT group was reduced respectively by 16.290 and 8.920 h and the time required to pass through the zone of maximum ice crystal formation for EFF-EFT-treated samples was shortened by 3.41 h. Moreover, a significant decrease in the thawing loss of 4.19% was recorded (P < 0.05). The surface hydrophobicity of myofibrillar proteins in EFF frozen muscle (16.16 μg) was significantly lower than that of the control, while that of EFT thawed muscle (9.45 μg) demonstrated a significant increase compared with the control (P < 0.05). The degree of protein denaturation in EFF-EFT-treated samples with denaturation temperatures of 55.130, 63.940 and 78.350 ℃ was lower than that in the control group. In conclusion, electrostatic field-assisted freezing and thawing can effectively improve the freezing and thawing rate of beef muscle, reduce the extent of myofibrillar protein denaturation, and decrease the thawing loss of beef muscle.