【作者】 莎丽娜；

【导师】 靳烨；

【作者基本信息】 内蒙古农业大学 ， 畜产品安全生产， 2009， 博士

【摘要】 本研究选择不同月龄自然放牧的苏尼特羊,采用常规分析、气相色普-质普联用(GC\MS)、SDS-凝胶电泳、高效液相色谱(HPLC)等方法对其产肉性能、肌肉食用品质、风味前体物质(脂肪酸、氨基酸)、肌纤维的发育特性、肌肉胶原蛋白特性等进行了分析,研究探讨了自然放牧苏尼特羊肉营养特性、组织结构特性,胶原蛋白特性。用试验数据说明了自然放牧苏尼特羊独特的肉质特性。试验结果表明:自然放牧苏尼特羊6月龄时活体重达27.11 kg、胴体重达12.52 kg、屠宰率达46.18%、净肉率38.96%。达到出栏水平。自然放牧苏尼特羊肌肉蛋白含量高、肌肉脂肪含量高、水分含量低;6月龄羔羊肉平均蛋白含量达19.76%、最高(背最长肌)达20.61%;平均水分含量为73.43%、最低(股二头肌)只有72.06%;平均脂肪含量达7.25%。肌肉胆固醇含量为27.97mg/100g,随着月龄的增加胆固醇含量显著降低(P﹤0.05)。6月龄时肌纤维直径为39.61μm,密度为376.09(根/mm2),不同部位肌纤维直径、密度都有显著差异(P﹤0.05);与对照组有显著差异(P﹤0.05)。自然放牧羊肌肉活动量大促进了肌肉发育及不同部位的差异。统计结果表明品种对肌肉蛋白含量、失水率、脂肪含量、肌纤维直径和密度等有显著影响(P﹤0.05)。但肌肉胆固醇的含量受品种的影响不明显。相关性分析结果表明剪切值与纤维直径、蛋白质含量呈显著正相关(P﹤0.05),与肌肉间脂肪含量、失水率呈显著负相关(P﹤0. 05);胆固醇含量与脂肪含量呈显著正相关(P﹤0.05)。自然放牧苏尼特羊肌肉中油酸含量高; 6月龄羔羊肉油酸:亚油酸比例为40:1,硬脂酸含量低、相对含量只有11.78%,鲜味氨基酸含量高,6月龄时已达22.66 mg/100mg,与对照组有极显著差异(P<0.01)。这可能是苏尼特羊肉香味浓厚、膻味低的主要原因。品尝试验结果也显示苏尼特羊肉香味浓郁,膻味低。自然放牧苏尼特羊肉中有一定保健功能的15烷酸和17烷酸、亚油酸含量高。肌肉中影响胆固醇含量的棕榈酸、豆蔻酸含量随月龄增加而减少,与胆固醇含量变化规律一致。苏尼特羊肌肉胶原蛋白含量随月龄的增加有显著增加趋势(P﹤0.05)。交联度指标吡啶诺林的含量随着月龄的增长而增加,月龄间差异极显著(P﹤0.01)。股二头肌中吡啶诺林含量显著高于背最长肌(P﹤0.05)。表明自然放牧羊后肢活动量充分,使肌肉结缔组织发达。肌肉总胶原蛋白中Ⅰ型占65%～85%,Ⅲ型占18%～25%,随着月龄的增加含有还原性胶联的Ⅰ型比例逐渐增加而含非还原型交联较多的Ⅲ型胶原比例反而下降。这与交联度的变化规律一致。相关性分析结果显示肌肉剪切值与总胶原、不溶性胶原、吡啶诺林含量呈极显著正相关(P﹤0.01),与溶解度呈显著负相关(P﹤0.05),其中相关系数最大的是吡啶诺林含量;肌肉中的脂肪含量与总胶原,不溶性胶原,胶原交联呈显著负相关(P﹤0.05)。说明肌肉嫩度最根本的影响因素是胶原的交联度。更多还原

【Abstract】 The natural grazing Sunit Sheep with different ages were selected as research group while Small-Tail Sheep with the same age as a control group. The meat production performance, the edible properties of muscle, the flavor precursor substances (fatty acid and amino acids) during growing, the growth characteristics of muscle fiber, and changes in muscle collagen were studied experimentally. The methods employed in this research were combination of normal analysis, Gas chromatography-mass spectrography (GC/MS), Electrophoresis (SDS), High performance liquid chromatography(HPLC) methods. Based on the tests, the characteristics of nutrition, structure and collagen of meat samples were investigated. The study has proved that natural gazing raised Sunit sheep produce excellent and unique characteristics of muscle meat.That Sunit Sheep reached 6 month age has the live body weight of 27.11kg, carcass weight of 12.52kg, dressing rate of 46.18%, the pure meat percentage of 38.96% was established by this research as a standard of raw material animals ready for meat industrySunit Sheep meat has low water loss, high rate of cooked meat, high lever of protein and low moisture. For lambs with 6 month age the water loss 4.16%, rate of cooked meat 57.86%, the average protein lever up to 19.76%, the yield of longissimus dorsi muscle up to 20.16%, and the moisture of biceps femoris muscle lowered to 72.06%. The average fat content in muscle for the 6 month aged animal was 7.25%, cholesterol lever was 27.97mg/kg and it significantly higher that with 12 month age (P<0.05), with the increase of age the cholesterol lever lowered. The diameter of muscle fiber 39.61μm and the fiber density 376.09 pieces/mm2, the muscle fiber diameter and the density were also different significantly along carcass position (P<0.05); It also showed a significant difference in that of yard raising Sunit Sheep (P<0.05). The movement of muscle caused by natural grazing greatly promoted the growth and the diversity of muscle position.Correlation study showed that the shear force value was highly correlated with muscle fiber diameter, fat content and cooked meat percentage (P<0.05), and highly negatively correlated with intermuscle fat content and water loss (P<0.05). The cholesterol lever was highly positive correlated with TBARS value and fat content (P<0.05).The animal meat has a high content of oleic acid, it was 37.23% for the 6 month age lamb and its ratio to the linoleic acid was 40:1. The content of stearic acid was down to 11.78% while it was 21.79% for Small-Tail Sheep raised in yard, and the difference was extremely significant (P<0.01). These contribute to the scarcity of off flavor of Sunit Sheep meatThe content of pentadecanoic acid and daturic acid were evidently higher that in control group (P<0.05), this contributes a certain health functions. The content of palmitic acid and myristic acid declined with age, and accorded with that of cholesterol levers.The contents of amino acids was high, Those were 22.66mg/100mg at 6 month age, 23.31mg/kg at 12 month age, and among the amino acids the content of glutamic acid was up to 14.32mg/100mg and 14.54mg/kg respectively.contributing to meat with nice flavor.The collagen content in the muscle of Sunit Sheep before 12 month age has a significant increase trend (P<0.05).Lever of pyridinoline, an index of cross-linkage degree, increased with age significantly (P<0.01), The lever of pyridinoline in biceps femoris muscle was significantly higher than that in the longissimus dorsi muscle (P<0.05). This indicates that the movement is sufficient for the rear limbs by natural grazing, in turn, it causes the structure of connective tissue to be more developed. Among the collagen the TypeⅠcollagen accounted for 65%-85% and the typeⅢcollagen accounted for 18-25%, the content of Type I collagen which is revertible increased with age while the content of the type III collagen which is invertible declined with age. This accorded with the extend of cross-linkage forming .Correlation study showed that the shear value was highly correlated with the total insoluble and soluble collagen contents and the lever of pyridinoline (P<0.01), and there was also a highly negative correlation between shear force value and solubility (P<0.05).The largest correlation coefficient was for lever of pyridinoline. The content of fat was significantly negative correlated with total insoluble collagen and cross-linkage. (P<0.05) This indicated that the radical factor affecting the tenderness of muscle is the degree of cross- linkage of collagen .更多还原