Physicochemical and sensory traits of meat from Santa Inês lambs slaughtered with different subcutaneous fat thicknesses

Physical (pH, color, tenderness, and cooking weight loss), chemical (moisture, crude protein, ash, and lipids) and sensory (odor, flavor, juiciness, and overall acceptance) characteristics of meat from Santa Inês lambs slaughtered with 2.0, 3.0, and 4.0 mm of subcutaneous fat thickness (SFT) were evaluated. Samples of the longissimus dorsi muscles were removed from 24 male uncastrated lambs distributed in a completely randomized design with three treatments and eight replicates. Weightings and ultrasound evaluations were performed every 14 days. No significant differences were observed for pH0h, which averaged 6.24. Lambs slaughtered with 4.0 mm SFT differed from the treatments with 2.0 and 3.0 mm as to the pH24h values. The meat from lambs slaughtered with 3.0 and 4.0 mm SFT showed a greater lightness (L*) value. Meat tenderness (2.21 kgf/cm2), cooking weight loss (13.90%), moisture (74.39%), and crude protein (22.10%) contents were not affected by the SFT. For the total lipid contents of the meat, significant differences were observed between the lambs slaughtered with 2.0 mm and those with 3.0 and 4.0 mm SFT. The sensory traits were not affected by the SFT with which the lambs were slaughtered. Lambs slaughtered with 4.0 mm SFT remained 33 days longer in feedlot and showed similar live weights at slaughter to those with 3.00 mm. It is recommended to slaughter Santa Inês lambs with a subcutaneous fat thickness of 3.00 mm.

本研究对皮下脂肪厚度（subcutaneous fat thickness, SFT）分别为2.0、3.0、4.0 mm的圣塔伊内斯（Santa Inês）羔羊的肉品特性展开评估，评估维度涵盖物理指标、化学指标与感官指标三类：其中物理指标包括pH值、色泽、嫩度及蒸煮损失；化学指标涵盖水分、粗蛋白、灰分与粗脂肪；感官指标则包含气味、风味、多汁性及整体接受度。实验采用完全随机设计，设置3种处理组，每组8个生物学重复，从24只未去势公羔的背最长肌（longissimus dorsi muscles）中采集肉样。每14天进行一次体重测定与超声评估。宰后0小时pH值（pH0h）未呈现显著组间差异，平均值为6.24。宰后24小时pH值（pH24h）方面，皮下脂肪厚度为4.0 mm的处理组与2.0、3.0 mm组存在显著差异。皮下脂肪厚度为3.0 mm与4.0 mm组的肉品亮度（L*值）更高。肉品嫩度（2.21 kgf/cm²）、蒸煮损失（13.90%）、水分含量（74.39%）及粗蛋白含量（22.10%）均不受皮下脂肪厚度的影响。肉品总粗脂肪含量方面，皮下脂肪厚度为2.0 mm组与3.0、4.0 mm组存在显著差异。所有感官性状均不受羔羊屠宰时皮下脂肪厚度的影响。皮下脂肪厚度为4.0 mm组的羔羊在育肥栏的饲养时长较其他组长33天，但其屠宰时的活重与3.0 mm组羔羊无显著差异。研究建议，圣塔伊内斯羔羊的适宜屠宰皮下脂肪厚度为3.00 mm。