藏绵羊不同部位骨骼肌的品质及脂肪酸组成特点分析

Main characteristics of meat quality and fatty acid composition among different skeletal muscles in Tibetan sheep

为了比较藏绵羊不同部位骨骼肌的品质及脂肪酸组成差异,本研究选取繁育在青海省海晏县的3岁成年藏绵羊母羊,分析其臂三头肌、冈上肌、股四头肌、背最长肌、腰大肌、胸斜方肌和腓肠肌7个部位肉品质及脂肪酸组成。肉品质分析结果表明,宰后45 min藏绵羊冈上肌的红度值(a^(*), redness)最高,背最长肌的亮度值(L^(*), lightness)最接近中间值,胸斜方肌宰后45 min和24 h肌肉的亮度、红度和黄度值均显著低于其他部位肌肉(P <0.05);胸斜方肌的pH显著高于除背最长肌和腰大肌外的其他部位肌肉(P <0.05);背最长肌失水率显著低于臂三头肌、冈上肌、胸斜方肌及腓肠肌(P <0.05);背最长肌剪切力值最小,显著低于臂三头肌、胸斜方肌和腓肠肌(P <0.05)。脂肪酸测定结果表明,藏绵羊7个部位共检测到30种脂肪酸,且所有部位中的饱和脂肪酸(SFA)>单不饱和脂肪酸(MUFA)>多不饱和脂肪酸(PUFA),背最长肌和胸斜方肌SFA含量显著高于除腰大肌之外的其余各部位肌肉(P <0.05),胸斜方肌中的肉豆蔻酸(C14:0)含量最高;背最长肌中的棕榈酸(C16:0)含量高于臂三头肌和腓肠肌(P <0.05);腓肠肌中PUFA含量显著高于胸斜方肌和冈上肌(P <0.05);腓肠肌PUFA/SFA值显著高于冈上肌、背最长肌和胸斜方肌(P <0.05);背最长肌n-6/n-3 PUFA的比值更接近最佳比值(1.0或2.0)。综合分析,藏绵羊背最长肌的品质最优,其与腓肠肌的脂肪酸组成和含量更符合人类健康膳食标准,而胸斜方肌中不利于人体健康的肉豆蔻酸含量最高。

To compare the skeletal muscle quality and fatty acid composition of different parts of Tibetan sheep, this experiment selected 3-year-old adult Tibetan sheep ewes bred in Haiyan County, Qinghai Province, and analyzed their triceps, supraspinatus, quadriceps femoris, longissimus dorsi, psoas major, trapezius thoracalis, and gastrocnemius for meat quality and fatty acid composition. The results of meat quality analysis showed that the redness value(a, redness) of the upper muscle of Tibetan sheep was the highest 45 min after slaughter, and the lightness value(L, lightness) of the longissimus dorsi was closest to the median value. The brightness, redness, and yellowness of the trapezius thoracalis muscles were lower than those of the other muscles at 45 min and 24 h(P < 0.05). The pH of the thoracic trapezius muscle was higher than that of the other muscles, except for the longissimus dorsi and psoas major at 24 h(P < 0.05). The water loss rate of the longissimus dorsi was lower than that of the triceps, supraspinatus, pectoralis trapezius, and gastrocnemius(P <0.05). The longissimus dorsi had the smallest shear force value, which was lower than that of the triceps, pectoralis trapezius,and gastrocnemius(P < 0.05). Fatty acid determination results showed that a total of 30 fatty acids were detected in seven parts of Tibetan sheep, and saturated fatty acid(SFA) > monounsaturated fatty acid(MUFA) > polyunsaturated fatty acid(PUFA) in all parts, and the SFA content of the longissimus dorsi and thoracic trapezius was higher than that of the psoas major. The content of myristic acid(C14 : 0) in the thoracic trapezius muscle was the highest among the rest of the muscles(P <0.05). The palmitic acid(C16 : 0) content in the longissimus dorsi muscle was higher than that in the triceps and gastrocnemius(P < 0.05). PUFA content in the gastrocnemius muscle was higher than that in the quadratus pectoralis and supraspinous muscles(P < 0.05). The PUFA/SFA ratio of the gastrocnemius muscle was higher than that of the supraspinatus, longissimus dorsi, and thoracic trapezius muscles(P < 0.05). The n-6/n-3 PUFA ratio of the longissimus dorsi muscle was closer to the optimal ratio(1.0 or 2.0). Comprehensive analysis showed that the quality of the longissimus dorsi of Tibetan sheep is the best, and its fatty acid composition and content in the gastrocnemius are more in line with human health dietary standards, while the content of myristic acid, which is not conducive to human health, is the highest in the thoracic trapezius muscle.