Effect of aging time on tenderness and colour stability of modified-atmosphere packaged beef from mature cows during shelf life

摘要

Eight Friesian mature cows were used to evaluate the effect of aging time on tenderness and colour stability of beef in modified-atmosphere packaging (MAP) during shelf life. Loins were removed from each carcass at 24 h post-mortem, and cut into three pieces assigned to 0, 6, and 21 days of ageing. After each ageing time, loin sections were cut into 3 cm steaks, packaged individually using MAP (80 % O_2: 20% CO_2) and tenderness and color stability were evaluated at 0, 3, 6, and 9 d of simulated retail display. Initial toughness was lower for beef aged for 21 d compared with beef aged for 6 and 0 d, which did not differ. Beef aged for 0, 6, and 21 d showed 17, 35, and 12% decrease in shear force over the 9 d of display, respectively. Shear force after 9 days of display was similar for beef aged during 21 and 6 d, and lower than unaged beef. At 9 d of display in MAP, beef aged for 21 d showed higher lightness, and lower redness and yellowness than unaged beef and beef aged for 6 d, which did not differ. Meat discoloration (R630-R580) was higher for beef aged for 21 d compared with the other ageing times, with a mean value (6.25) lower than the proposed threshold for consumer acceptability. Ageing for 6 d tend to improve beef tenderness with similar colour stability to unaged beef, while ageing for 21 d decreased colour stability reducing beef shelf life in MAP.