This study investigated the protein digestibility of aged beef using an infant in vitro digestion model. Semitendinosus muscles were vacuum-packed and aged for 0, 7, and 14 days at 4°C. Malondialdehyde content of raw and cooked beef increased with aging (P < .05). However, no changes in carbonyl content were observed for aged raw and cooked beef samples. The α-amino group content and myofibrillar fragmentation index of beef increased with aging (P < .05). The α-amino group content of cooked beef digesta increased upon aging (P < .05). Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the decrease in band intensities of actin in the digesta of aged beef. These results highlight the improvement in the protein digestibility of beef aged for 7 and 14 days. Therefore, aged beef is more desirable as complementary food owing to increased protein digestibility.

本研究使用婴儿体外消化模型研究了老化牛肉的蛋白质消化率。对半腱肌进行真空包装，并在4°C下老化0、7和14天。生牛肉和熟牛肉中丙二醛含量随年龄的增长而增加（P <  .05）。但是，对于老化的生牛肉和熟牛肉样品，未观察到羰基含量的变化。牛肉的α-氨基含量和肌原纤维断裂指数随年龄的增长而增加（P <  .05）。熟牛肉消化物的α-氨基含量随着年龄的增长而增加（P < .05）。十二烷基硫酸钠聚丙烯酰胺凝胶电泳显示，老化牛肉消化物中肌动蛋白的条带强度降低。这些结果突出了7天和14天熟牛肉的蛋白质消化率的改善。因此，由于增加的蛋白质消化率，陈年牛肉更适合作为辅助食品。