Fatty Acids Profile And Discriminant Model Of Pasturing And Barn Feeding Sheep Meat

Inner Mongolia is rich in natural pasturing cattle and sheep meat,and large-scale barn feeding is also rapidly developing.Fats and fatty acids(FAs)not only affect the nutritional characteristics,but also affect or determine the quality and taste of meat.FAs profile of sheep meat in pasturing and barn feeding lack systematic evaluation.A total of 234 pasturing sheep meats and 44 barn feeding sheep meats were collected from 9 counties in 4 cities in the east,central and west of Inner Mongolia.FAs were determined by gas chromatography(GC)methods,and conducted descriptive statistics and chemometric cluster analysis,and establish and optimize the discriminant model of pasturing and barn feeding sheep meat.Principal component analysis(PCA)of FAs in pasturing and barn feeding sheep meat of total sample,biceps femoris,longissimus dorsi and sheep tail.The clustering of these two feeding systems had significant separation.It is suggested that FAs profile can be used to establish chemometrics model to discriminates pasturing sheep meat from barn feeding.The n-3 series of polyunsaturated fatty acids,a-linolenic acid(a-C 18:3n3),C 14:1 and C14:0 in the pasturing meat were significantly higher than that of barn feeding meat,especially the ratio of n-3PUFA and ?-C18:3n3 were 6.2 times and 4.9 times that of barn feeding meat.n-6PUFA,linoleic acid(C18:2n6c),trans fatty acid(TFA),trans oleic acid(C18:ln9t),C17:0,C17:1 and C15:0 were significantly higher than that of pasturing meat.The ratio of S:M:P in the whole pasturing and barn feeding sheep meat is 9:8:1 and 6:7:1;the values of polyunsaturated fatty acids n-6/n-3 were 3 and 30,respectively.Clustering with each areas of sheep meat was consistent with the feeding systems.Samples of sheep meats from seven banners/counties in pasturing areas were clustered,which could not distinguish the region.Two banners in Bayannur farming area gathered together.The FAs composition of the three parts of biceps femoris,longissimus dorsi and sheep tail is different.But in the distinction between pasturing and barn feeding,the FAs changes in the three parts were the same.The n-3PUFA of pasturing mutton was significantly higher,and the content of TFA and n-6PUFA in barn feeding was higher.The three parts were analyzed separately by PCA,which had better clustering discrimination effect on pasturing and barn feeding than the total sample.However,the FAs of sheep tail has the longest clustering distance and the best differentiation between pasturing and barn feeding.SIMCA model was established by FAs of sheep tail,and the accuracy of internal and external verification 100%and 95%,respectively.The pairing and compatibility tests could not distinguish the two feeding systems and the regional differences.The cluster analysis and model based on chemometrics provide innovative ideas and methods for identifying the feeding systems of sheep meat.