关键词: 牛肉, 静电场, 冻结-解冻, 蛋白质, 保水性

Abstract: 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.

Key words: beef, electrostatic field, freezing-thawing, protein, water-holding capacity