Unhairing Technology Of Head And Hoof Of Yak In Qinghai Tibet Plateau And Nutritional And Functional Evaluation Of Collagen

Using yak scalp and hoof skin of Qinghai Tibet Plateau as raw materials,the basic composition was analyzed by national standard method.The unhairing technology of compound enzyme and the extraction technology of collagen protein by pepsin were discussed.The structure and amino acid composition of collagen protein were analyzed.The collagen peptide prepared by compound enzyme was digested by computer simulation,The results were as follows: the optimum technological parameters were as follows: enzyme concentration 1482 U/ml,pH 7.0,time 3.02 h and temperature 50?;The moisture content of yak scalp was 54.22%,crude protein 39.02%,fat 3.65%,ash 1.11%.The moisture content of yak hoof skin was 61.44%,crude protein 34.67%,fat2.09%,ash 1.06%.The results showed that yak skin was a source of high quality protein,and the composition of different parts of yak skin was different;The results showed that the optimum parameters of pepsin extraction of yak skin collagen were as follows: enzymolysis time 17.9h,enzyme dosage 2.0%,solid-liquid ratio 1:25,temperature 34 ?,and the extraction rate was 26.37%;Pepsin extraction method can retain the triple helix structure of collagen,and yak skin collagen has typical structural characteristics of type ? collagen Yak skin collagen has many structural characteristics of type ? collagen;There are 18 kinds of amino acids in yak skin collagen,among which glycine(Gly)is the highest,accounting for 31% of the total amino acids,followed by proline(pro)and hydroxyproline(Hyp);The results showed that the optimal technological parameters for the preparation of antioxidant peptides from yak skin were as follows: enzymatic hydrolysis time4.00 h,enzyme dosage 5860.45U/g,substrate concentration 2.98%,temperature 50 ?.