Post-mortem oxidative stability of three yak (Bos grunniens) muscles as influenced by animal age

• Oxidative stability of yak steaks was influenced by muscle source and animal age.
• Activities of antioxidant enzymes increased with the animal age.
• Myoglobin oxidation was lowest in Longissimus thoracis.
• Longissimus thoracis from 3.5 year-old yaks exhibited the lowest metmyoglobin level.

The influence of animal age and muscle source on the oxidative stability of yak steaks was examined. Longissimus thoracis (LT) muscles from yaks of different age groups (0.5, 1.5, 2.5, and 3.5 years), and three muscle sources of LT, Psoas major (PM), and Biceps femoris (BF) from yaks of 0.5, 1.5, and 2.5 years, were evaluated for metmyoglobin content, activity of antioxidant enzymes, and antioxidant capacity. Oxidative stability was influenced (P < 0.05) by muscle source and animal age. LT steaks from 0.5, 1.5, and 2.5 year old yaks exhibited lower (P < 0.05) metmyoglobin content than their PM and BF counterparts. Furthermore, LT steaks from 3.5 year old yaks demonstrated lower (P < 0.05) metmyoglobin content and greater (P < 0.05) activities of antioxidant enzymes than LT steaks from other age groups. These results indicated the necessity to develop muscle- and age-specific processing strategies to improve color and oxidative stability of yak meat.