Studies And Evaluation On Amino Acids Fingerprint Profile Of Six Livestock Milk

Along with the rapid development of cow dairy industry in China,special livestock milk also started to be exploited and consumed gradually.However,its nutritional characteristics,especially the amino acids(AAs)properties,have not been systematically studied.Which animal milk's AAs profile more similar to human milk? Whether milk AAs profile is as species-specific as protein,and whether AAs profile modeling can realize identifying the authenticity of livestock milk,are all worth a new round of research with the help of new strategies,principles and methods.A total of 55 representative milk samples of Holstein cow(cow),Mongolian horse(horse),Bactrian camel(camel),goat,buffalo and yak were collected from Inner Mongolia,Guangxi and Sichuan provinces.Eighteen AAs of whole milk,casein and whey protein of the six animals were determined in two rounds,after data quality test,312 sets of data were obtained for descriptive statistics,principal component analysis(PCA)and essential amino acid(EAA)nutritional evaluation.As a results,the amino acid absolute content(mg/g)of whole milk,casein and whey protein of six livestock were significantly different(P<0.01).PCA on percentage of AAs(AA/TAA,%)showed that,clustering of six livestock milk samples in 3D space conformed to taxonomy class of the animals species,four Bovidae animal milk samples clustered in the same region,while cluster horse and camel milk samples were far in another two regions.AAs profile of casein and whey protein of six livestock milk shows the species specificity.The clustering effect of casein was best,AAs profile of livestock milk has obvious species specificity,which is sufficient to establish a robust and accurate species authenticity discrimination model.AAs profile of mixed human milk AAs data that published by FAO/WHO were extremely different from that of the six animal milk,in PCA on whole milk AAs,the 3D spatial projection point of human milk was far from the cluster of six animal,while the later six clustering more closer,respectively horse milk cluster was closest to human milk and camel milk was the next closer for they were locating in the same below side of factor1 axis,opposite the Bovidae cluster;in PCA on casein AAs profile,human milk was close to Bovidae animals;while when it comes to whey protein AAs,human milk was closer to the goat whey;in general human milk AAs profile was closer to whey protein.Essential amino acids Pattern(EAAP)of whole milk,casein and whey protein of the six animal were significantly different from human milk(P<0.05);PCA on whole milk EAAP data indicated that goad and horse were close to human milk successively;Casein EAAP PCA showed buffalo and yak were relatively closer to human milk;when it comes to whey protein EAAP,human milk successively close to camel,yak,horse and goat.Generally livestock whole milk,casein and whey protein could not completely replace human milk.AAs profile of organic and non-organic cow milk was obviously different,it implies that the AAs fingerprints of milk is not only species specific,but also related to feed and feeding pattern,worth further and in-depth research.SIMCA animal milk authenticity discrimination models were established on AAs fingerprint of whole milk,casein and whey protein,the accuracy of internal validation all were 100%,while in external validation,casein model was most accurate with 98.19%,and the lowest was whey model with87.78% accuracy.human milk didn't match any one of the six livestock milk,however,whey protein AAs showed the closest to human milk than whole milk and casein.In conclusion,Chemometrics cluster analysis is more visual and holographic than traditional descriptive statistics and protein AAs nutriological evaluation.Which provided a new innovative and creative strategy,principal,and methods to nutritional property evaluation and authentication on dairy product.