Abstract: In this study, proximate nutrients of raw milk of Holstein, yak, Jersey cattle, Murrah buffalo, Nili-Ravi buffalo, hybrid F1 buffalo and multiple-generation hybrid buffalo were analyzed, and the contents of proteins and amino acids as well as the buffer capacity of milk was determined. The results showed that the fat, protein and total solid contents in Murrah, Nili-Ravi, hybrid F1 and multiple-generation hybrid buffalo milk were 6.86%, 7.99%, 8.34%, 8.69%, 5.75%, 5.14%, 5.78%, 5.58%, and 17.07%, 18.79%, 19.73% and 19.88%, respectively, all of which were significant higher than those in another three kinds of raw milk. The lactose contents of yak and Jersey were 5.09% and 5.17%, which were significantly higher than those in another five kinds of raw milk. SDS-PAGE showed that milk protein in buffalo had unknown bands except BSA, α-CN, β-CN, κ-CN, β-Lg and α-La. The buffalo milk revealed the best buffer capacity, which was followed by yak and Jersey milk, and Holstein milk exhibited the lowest buffer capacity.

Key words: milk, nutrient composition, buffer capacity, amino acid