Amino acid composition and functional properties of collagen polypeptide from Yak (Bos grunniens) bone

Collagen polypeptide was prepared from Yak bone by applying papain as a catalyst. Its relative molecular weight distribution and amino acid composition were determined. Moreover, its main functional properties including water and oil absorption, water-holding capacity, emulsifying ability and stability, foaming ability and foam stability were investigated. The polypeptide had a molecular weight distribution of 11.7–43 kDa, in which most distributed at 11.7–25.3 kDa. It was high in glycine, alanine, proline, hydroxyproline and glutamic acid but low in methionine, tyrosine and histidine, the total amino acid amount being 88.06 g/100 g. The polypeptide showed good water adsorption, water-holding capacity, oil absorption, emulsifying and foaming properties. It is hoped to be applied in food and cosmetic.