Sensory quality and histochemical characteristics of longissimus thoracis muscle between Hanwoo and Holstein steers of different quality grades

This study compared the carcass traits, meat quality characteristics, palatability, and histochemical characteristics of low-marbled Hanwoo and Holstein steers of different beef quality grades (1, 2, and 3). No differences were observed in carcass weight, muscle pH_{24 h}, and cooking loss between the groups (p>0.05); however, quality grade 1 of Hanwoo steers (HA1) showed a darker muscle surface compared to grade 1 of Holstein steers (HO1) (30.9 vs. 33.9, p<0.05). The HA2 group exhibited a lower value of Warner-Bratzler shear force compared to the HO1 and HO3 groups (60.8 vs. 69.2 and 87.8 N, p<0.001). For sensory quality attributes, steaks from the HA1 group showed higher scores of softness, initial tenderness, and amount of perceptible residue than steaks from the HO1 group (p<0.001). Within the quality grade 2, Hanwoo steers had a higher score of softness compared to Holstein steers (p<0.001). There were no differences in juiciness and flavor intensity between Hanwoo and Holstein steers at the same quality grade (p>0.05). This difference in tenderness attributes between the breeds within the quality grade was associated with morphological traits of muscle bundle, and Hanwoo steers had smaller bundle area (0.37 vs. 0.50 mm², p<0.05) and higher fiber number per bundle (88.2 vs. 121, p<0.05) compared to Holstein steers. Therefore, bundle characteristics of longissimus thoracis muscle can be crucial for explaining factor for the explanation of tenderness variations between different breeds at the same beef quality grade or marbling.