Authors : H.L. Wan, L.P. Zhang, M.A. Brown, X.J. Wu, J.H. Wang, L. Yang, Z. Deng and J.P. Wu
Abstract: Meat from yak (Bos grunniens) is a primary staple in diets of people in western China. Yak meat has low-fat content, high protein and good amino acid and fatty acid profiles. However, meat from yak may be less tender than meat from Bos taurus cattle. Gannan Black yaks (n = 181) were used to investigate the effects of age at harvest and aging days on meat quality characteristics of M. longissimus dorsi. Yaks were harvested at 2, 3 and 4 year of age and muscles of each yak carcass were aged for 0, 1, 3, 7, 14 or 21 days at 4°C and frozen at -20°C until analyzed. Age at harvest affected shear force and percentage fat, protein and moisture (p<0.05). Aging days affected shear force, retort cooking loss, pressing loss, moist cooking loss, pH, percentage fat, moisture (p<0.01) and protein (p<0.10). There were interactions between aging days and age at harvest for shear force, moisture and protein (p<0.01). Aging days appeared to have a greater effect on shear force than age at harvest and tended to moderate the age at harvest effect on shear force. When cooked in retortable bags, cooking loss decreased until 3 days postmortem after which it remained relatively constant. When steam cooked, meat aged 7 days had the lowest cooking loss (p<0.05). Pressing loss decreased until 3 days postmortem then remained relatively constant. After thawing, pH decreased during the 21 days period of postmortem aging with the greatest decline in the first 24 h (6.68-5.73 from 2-24 h postmortem). Results suggest that aging yak meat 7 days is sufficient for acceptable tenderness and meat quality.
H.L. Wan, L.P. Zhang, M.A. Brown, X.J. Wu, J.H. Wang, L. Yang, Z. Deng and J.P. Wu, 2011. Influence of Aging Days and Age at Harvest on Meat Quality of Gannan Black Yak. Journal of Animal and Veterinary Advances, 10: 1089-1096.