The Effects of Hot vs. Cold Boning on Eating Quality of New Zealand Grass Fed Beef

Abstract

Sides of the 40 selected carcasses were alternately assigned to both conventional chilling and cold boning (CB) or hot boning (HB). Fabrication of CB sides took place after overnight chilling (20 h postmortem) and subsequent carcass grading, while fabrication of HB sides occurred on the day of slaughter within 60 min of exsanguination. Five muscles were removed, including the longissimus lumborum (LL), longissimus thoracis (LT), psoas major (PM), gluteus medius (GM), and semimembranosus (SM) for consumer evaluation, compositional analysis, and sarcomere length determination. Cold boning muscles had longer (P < 0.05) sarcomere lengths compared to HB muscles, expect for the GM and SM. Chilling treatment and postmortem aging (7, 21, or 35 d postmortem) had an impact on eating quality, but these results varied by muscle. Cold shortening could be responsible for the differences in sarcomere length and ultimately differences in tenderness between HB and CB muscles. Based on consumer evaluations, HB is not recommended for LT or PM due to the reduction (P ≤ 0.02) of tenderness and overall liking scores for these subprimals; however, HB and early removal of muscles like the SM benefited (P < 0.01) from an eating quality standpoint for all palatability traits, and was neutral (P ≥ 0.21) for tenderness, juiciness, flavor, and overall liking of the LL and GM. Postmortem aging did not affect (P ≥ 0.07) eating quality of the GM and PM, but improved (P < 0.01) tenderness of LT and SM, as well as the tenderness, juiciness, flavor liking, and overall liking of the LL.