Carcass characteristics and sensorial evaluation of meat from Nellore steers and crossbred Angus vs. Nellore bulls

ABSTRACT. This study evaluated animal performance, carcass characteristics and meat quality of 36-month old Nellore steers finished in pastures (n = 10) and 20-month old Angus vs. Nellore bulls finished in feedlot (n = 10). Final body weight, carcass weight, characteristics, conformation and fat thickness, were higher (p < 0.001) for the Nellore steers than for Angus vs. Nellore bulls. Water losses during chilling (24 hours, 4oC) were lower (p < 0.05) for Nellore steers than for the Angus vs. Nellore bulls. Muscle percentage on the 6th rib was higher (p < 0.05) for the Nellore steers than for Angus vs. Nellore bulls; while bone percentage was lower (p < 0.05) for Nellore steers. After 7 and 14 days of ageing, the L* meat value was higher for the Nellore steers than for the Angus vs. Nellore bulls; the L* meat value was similar (p > 0.05) throughout the ageing period for the Angus vs. Nellore bulls, but higher in meat from the Nellore steers (p < 0.05). Genetic group had no effect (p > 0.05) on meat a* value (redness). Likewise, ageing time had no effect on a* in both genetic groups, and genetic group had no effect (p > 0.05) on meat b* value (yellowness). On the other hand, b* was increased after day 7 of ageing for the bulls from the two genetic groups. Thawing and cooking losses were lower for Nellore steers after day 7 of aging (p < 0.05). The meat of the Angus vs. Nellore bulls was more tender (p < 0.05) at all ageing times studied (1, 4, 7 and 14 days) than the meat of the Nellore steers. Genetic group had no effect (p > 0.05) on lipid oxidation; however, lipid oxidation increased after day7. Meat from Nellore steers contained a higher percentage of saturated fatty acids (SFA), a lower percentage of unsaturated (UFA) and monounsaturated fatty acids (MUFA) and a similar percentage of polyunsaturated fatty acids (PUFA) than the meat from Angus vs. Nellore bulls. Intramuscular fat from Nellore steers had a more favourable n-6:n-3 fatty acid ratio than that from Angus vs. Nellore bulls (4.37 vs. 11.45, respectively). Tenderness, flavour and overall acceptability were higher (p < 0.001) for meats of the Nellore steers, regardless of ageing time (1, 4, 7 and 14 days).

摘要。本研究评估了10头36月龄内洛尔（Nellore）阉牛放牧育肥，与10头20月龄安格斯（Angus）公牛及内洛尔公牛舍饲育肥的动物生产性能、胴体性状及肉品质。内洛尔阉牛的终末体重、胴体重、胴体性状、体型结构与背膘厚度均极显著高于安格斯公牛与内洛尔公牛组（p<0.001）。内洛尔阉牛的24小时4℃冷却失水率显著低于安格斯公牛与内洛尔公牛组（p<0.05）。内洛尔阉牛的第6肋肌肉率显著高于安格斯公牛与内洛尔公牛组（p<0.05），而其骨骼率则显著低于该组（p<0.05）。排酸熟化7天和14天后，内洛尔阉牛肉的L*亮度值均显著高于安格斯公牛与内洛尔公牛组；安格斯公牛与内洛尔公牛组的L*值在整个排酸熟化周期内差异不显著（p>0.05），但内洛尔阉牛肉的L*值随熟化时间显著升高（p<0.05）。遗传分组对肉品a*红度值无显著影响（p>0.05）。同样，排酸熟化时间对两个遗传分组的a*值均无显著影响，且遗传分组对肉品b*黄度值也无显著影响（p>0.05）。但两个遗传分组的肉品b*值均在熟化7天后显著升高。排酸熟化7天后，内洛尔阉牛的解冻失水率与烹饪失水率均显著更低（p<0.05）。在所有研究的排酸熟化时间（1、4、7和14天）下，安格斯公牛与内洛尔公牛组的肉品嫩度均显著高于内洛尔阉牛组（p<0.05）。遗传分组对脂质氧化水平无显著影响（p>0.05），但脂质氧化水平在熟化7天后显著升高。与安格斯公牛与内洛尔公牛组相比，内洛尔阉牛肉的饱和脂肪酸（SFA）占比更高，不饱和脂肪酸（UFA）与单不饱和脂肪酸（MUFA）占比更低，而多不饱和脂肪酸（PUFA）占比无显著差异。内洛尔阉牛的肌内脂肪n-6:n-3脂肪酸比值更优，两组分别为4.37与11.45。无论排酸熟化时间为1、4、7还是14天，内洛尔阉牛肉的嫩度、风味与总体可接受性均极显著更高（p<0.001）。