Comparison And Analysis Of Meat Quality Of Different Breeds,Ages And Parts

As a main source of red meat,mutton has important nutritional value in people’s diet,because it contains biological protein,minerals and vitamins necessary for human health.Mutton quality is affected by many factors,including variety,age,location,gender,feeding level,slaughter mode and season.In this study,six Tan sheep,six Tibetan sheep,six Ujimqin sheep and six Hu sheep(6 months old,longissimus dorsi),six Tan sheep(2 months old and 12 months old,longissimus dorsi)and six Tan sheep(6 months old,biceps femoris and triceps brachii)were selected.According to the national standard,the nutritional quality,processing and edible quality and flavor substances were analyzed and compared.In order to clarify the differences of mutton quality in different breeds,different months and different parts of sheep,and provide reference for improving mutton quality.(1)Nutritional quality There were significant differences in ash content and fat content among different breeds of sheep(P<0.01).Ujimqin mutton had the highest fat content and Tan mutton had the highest water content.The contents of fat and crude protein were significantly different in different months(P < 0.05).The order of fat content and protein content were in the order of 12 months old,6months old and 2 months old.The fat content and protein content in different parts were significantly different(P<0.05),the highest in biceps femoris.There was significant difference in the content of essential amino acids between Tibetan mutton and Hu mutton(P<0.01).The content of essential amino acids in 12-month-old lamb was significantly higher than that in other 2-month-old lamb(P < 0.05).There was significant difference in the content of essential amino acids in different parts of Tan sheep at the age of 6 months(P<0.05).EEA/TAA of mutton of different breeds,months and parts were close to 40%,EEA/NEAA was higher than 60%,which indicated that the amino acid score of four kinds of mutton protein reached the ideal model,and the quality was excellent.The contents of monounsaturated fatty acids in Tan mutton and Ujimqin mutton were significantly higher than those in other two breeds(P<0.05),and the contents of polyunsaturated fatty acids in Tibetan mutton were significantly higher than those in Ujimqin mutton and Hu mutton(P<0.05).There was significant difference in the content of polyunsaturated fatty acids in different months of age(P<0.05),and the content of polyunsaturated fatty acids in 6 months of age was the highest.The content of polyunsaturated fatty acids in longissimus dorsi muscle was significantly higher than that in triceps brachii muscle(P<0.05).The n-6/n-3 ratios of Tan mutton,Tibetan mutton and Ujimqin mutton were 2.97,4.58 and 5.64,respectively.The composition,content and proportion of fatty acids were close to human needs,and the n-6/n-3 ratio of Tan mutton was the best.(2)The edible quality The p H values of Tan mutton,Tibetan mutton,Hu mutton and Ujimqin mutton were in the normal range,and the meat color was better.The cooked meat rate of Tibetan mutton was the highest,and the shearing force of Tan mutton was the lowest,which indicated that the edible quality of Tibetan mutton was better.There was no significant difference in the water loss rate of different months and different parts of beach mutton(P>0.05).The cooked meat rate of 2-month-old and 6-monthold beach mutton was significantly different,the highest in 6-month-old beach mutton,and relatively low in 2-month-old beach mutton.There was significant difference in shear stress among different months of age(P<0.01),and 2 months of age was the tenderest.The cooked meat rate of biceps femoris was significantly lower than the other two parts(P<0.01),and the shear force of triceps brachii was significantly higher than that of biceps femoris(P<0.05).In conclusion,the processing quality of longissimus dorsi of Tan sheep aged 6 months was better.(3)Flavor compounds Headspace gas chromatography-ion mass spectrometry(hs-gc-ims)was used to analyze the volatile components in Mutton of different varieties,ages and parts.41,29,35 and 45 volatile compounds were detected in Tan mutton,Tibetan mutton,Hu mutton and Ujimqin mutton,respectively.According to the signal intensity of volatile compounds,GC-IMS and PCA can identify mutton samples of different varieties,different months and different parts,and establish the fingerprint of volatile compounds.This method can be used for rapid and comprehensive analysis of volatile components in mutton.