The Chemical Composition and Nitrogen Distribution of Chinese Yak (Maiwa) Milk

Abstract

The paper surveyed the chemical composition and nitrogen distribution of Maiwa yak milk, and compared the results with reference composition of cow milk. Compared to cow milk, yak milk was richer in protein (especially whey protein), essential amino acids, fat, lactose and minerals (except phosphorus). The contents of some nutrients (total protein, lactose, essential amino acids and casein) were higher in the warm season than in the cold season. Higher ratios of total essential amino acids/total amino acids (TEAA/TAA) and total essential amino acids/total non essential amino acids (TEAA/TNEAA) were found in the yak milk from the warm season. However its annual average ratio of EAA/TAA and that of EAA/NEAA were similar to those of cow milk. Yak milk was rich in calcium and iron (p < 0.05), and thus may serve as a nutritional ingredient with a potential application in industrial processing.

Influence of succinylation on the conformation of yak casein micelles

“…The pellet was freeze dried to constant weight using vacuum freeze-drying machine (GLZ-0.4, Su Yuan Zhong Tian scientific Inc., Beijing, China). Total nitrogen and casein nitrogen contents in the dried pellet were tested by the method of Li et al (2011). Non casein nitrogen content was the difference between total nitrogen content and casein nitrogen content.…”

“…Annual yak milk production has increased to 40 million tons (Li et al, 2011). Yak caseins are widely used in the production of high quality food ingredients, soaps, glues, leather polishing reagents, and clothing, among others.…”

Isolation and identification of lactic acid bacteria (Lactobacillus plantarum YS2) from yak yogurt and its probiotic properties

“…Yak provides livestock, meat, fur and other livestock products for Tibetan herdsmen, which is an important economic source of local people [2]. Compared with normal milk, the yak milk is rich in protein, essential amino acids, fat, lactose and minerals [3]. With fresh yak milk as raw material, the traditional fermented yak yogurt is kind of flavored dairy product of a low alcohol content, which is made from various lactic acid bacteria and yeasts and so on, as a complex microbial system with many excellent characteristics of lactic acid bacteria.…”

Effect of microbial transglutaminase crosslinking on the functional properties of yak caseins: a comparison with cow caseins

“…In conclusion, mTGase treatment decreased casein solubility. Yak caseins had lower solubility than cow caseins because of their larger particle diameter and higher mineral content (calcium, magnesium, and phosphorus), resulting in more mineral bonds and higher conformational stability than cow caseins (Wang et al 2013;Li et al 2011). Intra-and intermolecular crosslinks were formed via mTGase modification.…”