Lee Seonmin, Jo Kyung, Jeong Hyun Gyung, Choi Yun-Sang, Jung Samooel
Division of Animal and Dairy Science, Chungnam National University, Daejeon, 34134, South Korea.
Research Group of Food Processing, Korea Food Research Institute, Wanju, 55365, South Korea.
Heliyon. 2023 Apr 19;9(5):e15611. doi: 10.1016/j.heliyon.2023.e15611. eCollection 2023 May.
The protein digestibility of beef at three prefreezing temperatures (freezing at -20 °C, F20; freezing at -50 °C, F50; and freezing at -70 °C, F70) and aging periods (4, 14, and 28 days) was investigated using an infant digestion model. The increased cathepsin B activity in the frozen-then-aged treatments ( < 0.05) resulted in a higher content of 10% trichloroacetic acid-soluble α-amino groups than in the aged-only group on days 14 and 28 ( < 0.05). F50 had the most α-amino groups in the digesta and digested proteins under 3 kDa on day 28 ( < 0.05), with the disappearance of actin band in the digesta electrophoretogram. The secondary and tertiary structures of myofibrillar proteins revealed that F50 underwent irreversible denaturation ( < 0.05), especially in the myosin fraction, while F20 and F70 showed protein renaturation during aging ( < 0.05). In general, prefreezing at -50 °C then aging can improve the protein digestibility of beef through freezing-induced structural changes.
使用婴儿消化模型研究了牛肉在三种预冻温度（-20°C冷冻，F20；-50°C冷冻，F50；-70°C冷冻，F70）和成熟时间（4天、14天和28天）下的蛋白质消化率。在冷冻后成熟处理中，组织蛋白酶B活性增加（P<0.05），导致在第14天和第28天，10%三氯乙酸可溶性α-氨基的含量高于仅成熟组（P<0.05）。在第28天，F50在消化物和3 kDa以下的消化蛋白质中具有最多的α-氨基（P<0.05），消化物电泳图谱中的肌动蛋白条带消失。肌原纤维蛋白的二级和三级结构显示，F50发生了不可逆变性（P<0.05），尤其是在肌球蛋白部分，而F20和F70在成熟过程中显示出蛋白质复性（P<0.05）。一般来说，在-50°C预冻然后成熟可以通过冷冻诱导的结构变化提高牛肉的蛋白质消化率。
