Comparative Study On Meat Quality Of Different Positions Of Jiulong Yak

In this study,36-month-old healthy and normal development Jiulong yaks were selected as test objects. To detect their nutritional components, processing and edible quality, fatty acid composition and volatile flavor compounds, different parts of Jiulong yaks, including the neck, highrib, striploin and knuckle, were analyzed by advanced equipment such as the flame atomic absorption spectrometer, automatic amino acid analyzer, electronic nose and GC-MS. Results are shown as follows:1.Nutritional componentsResearches showed that there was no significant difference in moisture content among different parts, while the chuck’s relative water content is the highest, accounting for 75.89%. The highest protein content is the knuckle, accounting for 23.13g/100g, followed by the striplion which had a small gap between the protein content. While for the chuck and highrib, a big gap existed there. The knuckle contained much higher than that in the chuck or highrib, and the difference was significant (p<0.05). The highrib had the highest level of fat content accounting for 2.11g/100g, which is significantly higher than that in the knuckle (p<0.05). The mineral elements, such as iron, zinc, copper, calcium and so on, were significantly higher in knuckle than in neck (p<0.05). The content of phosphorus in the highrib was much high than in others (p<0.05). The total amino acid content of highrib, striplion and knuckle was significantly higher than that in neck. Knuckle’s essential amino acid content is relatively higher. And the neck’s non-essential amino acid content were the lowest. The results showed that the meat of Jiulong yak is high protein and low fat, and it is high quality meat. However, the nutrient varies from different parts of the meat. From the aspect of conventional nutrition, striploin and knuckle contained relatively remarkable nutrition.2.Processing and edible qualityHighrib and striplion had the maximum degree of brightness. The value of L* values were 38.41 and 37.98, respectively, which is significantly higher than that in chuck or the knuckle (p<0.05). The knuckle had the biggest value of A* and the reddest color. The highrib and striplion had the smallest muscle fiber, which is significantly lower than the knuckle (p<0.05). And the highrib had the smallest shearing force about 62Kg/cm~2 (p<0.05). Analyses indicated that the highrib and striplion were better than the neck and the knuckle in color, tenderness and texture. The pH24 value of the four parts of were in reasonable range. The drip loss rate and water loss rate of the chuck were the highest for about 2.15% and 32.05%, respectively. The knuckle had the highest cooked rate, followed by the highrib and striplion.In other words, highrib, striplion and knuckle are better than the neck to be used for processing and edible quality.3. Fatty acidDifferent types and contents of fatty acids vary from different parts of Jiulong yak meat, but the saturated fatty acids (SFA) are important in the total amount of fatty acids. Both of them are dominated by palmitic acid and stearic acid. The results demonstrated that the highrib contained the highest level of saturated fatty acid (50.56%), while the knuckle had the lowest (7.02%). For the unsaturated fatty acid, much difference were between the chuck and the knuckle (p<0.05). While little difference existed between highrib and striplion. The content of the monounsaturated fatty acid (MUFA) had little significant difference between the four parts. And the knuckle contained higher polyunsaturated fatty acid (PUFA) (p<0.05). From the analysis, there were differences of fatty acid quality between the four parts. The highrib, knuckle and sirloin were more suitable for Chinese people’s diet structure through the comprehensive evaluation of the fatty acid content, species, the P/S value and the n-6/n-3 value.4.Volatile flavor compoundsVarious volatile flavor compounds existed in different parts of Jiulong yak meat. The highrib had the most volatile flavor compounds up to 74 kinds, followed by the striplion which had 73 kinds. The chuck had 70 different kinds of volatile flavor compounds. However, even the fewest is up to 63 kinds in knuckle. According to the detected volatile flavor which can be mainly divided into seven categories. Respectively, they are alcohols, aldehydes, acids, hydrocarbons, ketones, heterocyclic and esters. The volatile flavor content of highrib meat was relatively the highest, about 85.03%, which is followed by striplion about 73.4%. Then it was followed by the chuck about 55.86%. And the lowest is knuckle for about 49.55%. According to the the types and contents of volatile flavor compounds, the highrib and striploin had more intense flavor compared to the knuckle.According to the evaluation of the conventional nutritional ingredients, processing and eating quality, the types as well as proportion of fatty acid content and the volatile flavor compounds contents and types, the highrib and striploin had better qualities, both of which were high-grade meat. They are high-grade meat, and suitable for rinse, fried, fried and other cooking methods. While followed by the neck and knuckle, they were suitable for braising, stewing, boiling, stew, stewed and other cooking methods.