Fatty Acid Composition of Yak (Bos grunniens) Cheese Including Conjugated Linoleic Acid and trans-18:1 Fatty Acids

Abstract

The esterified fatty acid composition of cheese (YC) from yak (Bos grunniens), reared in the highlands of the Nepalese Himalayas, was studied using capillary gas-liquid chromatography and compared with that of dairy cow Cheddar cheese (DC) purchased in a local market. The YC was collected from Dolakha, Nepal. The YC had a lower (P < 0.001) myristic acid (C14:0; 6.7 vs 10.3%, YC vs DC, respectively) and palmitic acid content (C16:0; 23.3 vs 29.2%, YC vs DC, respectively) compared to DC. The YC had a lower (P < 0.01) total medium-chain saturated fatty acids (C10:0-C16:0) content compared to DC (36.7 vs 47.3%, YC vs DC, respectively). On the other hand, the YC had a 24.8% higher (P < 0.01) level of total long-chain saturated fatty acids (C17:0-C26:0) and a 3.2 times higher (P < 0.001) content of total n-3 PUFA than DC. The ratio of n-3 PUFA to n-6 PUFA in YC was 0.87 compared to 0.20 in DC. YC had a 2.8 times higher (P < 0.001) total trans-18:1 (9.18 vs 3.31%, YC vs DC, respectively) content. The percentage of vaccenic acid (trans-11-C18:1) in YC was 4.6 times higher (6.23 vs 1.35% of total fatty acids, YC vs DC, respectively) than in DC. Vaccenic acid constituted 67.9% of total trans-C18:1 in YC. The ∆9-desaturase index for YC was lower than that of DC. The total conjugated linoleic acid (CLA) content in YC was 2.3% of total fatty acids compared to 0.57% in DC. The cis-9, trans-11 CLA isomer in YC constituted 88.5% of the total CLA. The results suggest that cheese from yak, grazed on Himalayan alpine pastures, may have a more healthful fatty acid composition compared to cheese manufactured from dairy cattle fed grain-based diets.

Science of Camel and Yak Milks: Human Nutrition and Health Perspectives

“…These peptides are multifunctional bioactives with potential use for producing value-added functional foods and proteins [34]. Compared to cow milk fat, n-3 PUFA in yak milk fat is extremely higher (e.g., 3.2 times) [35]. The n-3 PUFA to n-6 PUFA ratio in yak cheese was 0.87, but only 0.20 in cow cheese.…”

Grass-based ruminant production methods and human bioconversion of vaccenic acid with estimations of maximal dietary intake of conjugated linoleic acids

“…According to a recent study, a VA:RA ratio of approximately 3:1 was observed in milk, butter, and cheese of cows on a modified diet to increase CLA in their milk . Somewhat lower VA:RA ratios were found in cheese from yak and cow (2.4:1 and 2.7:1, respectively), with expectedly higher amounts of both VA (2.27% versus 0.57% of FAME) and RA (6.23% versus 1.35%) in yak-derived cheese due to altitude and grass diversity (Or-Rashid et al, 2008). These results correspond to 4.0 and 4.6 times higher contents of VA and RA, respectively, in yak compared with cow cheese.…”

“…Animals in modern production systems are fed on silage and crop concentrate rather than pasture and this leads to a great reduction in CLA content in foods derived from these animals and consequently to lower CLA availability in human diets. It has been repeatedly shown that an animal-adapted feeding pattern, i.e., grazing for cows, not only increased CLA in meat and dairy products, but also mono-(MUFA), polyunsaturated (PUFA), n À 3 fatty acids, and VA content, while at the same time reduced saturated fatty acids (SFA) and increased the n À 6/n À 3 ratio substantially (Bisig et al, 2008;Couvreur, Hurtaud, Lopez, Delaby, & Peyraud, 2006;Dannenberger et al, 2004;Dewhurst, Shingfield, Lee, & Scollan, 2006;French et al, 2000;Garcia, Pensel, et al (2008); Hollo et al, 2005;Kraft, Kramer, Schoene, Chambers, & Jahreis, 2008;Or-Rashid, Odongo, Subedi, Karki, & McBride, 2008).…”

Macro and micro elements profile of yak (Bos grunniens) milk from Qilian of Qinghai plateau

“…Furthermore, the composition of yak milk is higher than that of Jersey and Holstein dairy cows. The total dry matter is around 17-18% during the main lactating period, fat content is around 6.5%, protein and lactose are each around 5.5%, and ash 0.8% (Or-Rashid et al, 2008). Concentrations of unsaturated fatty acid, such as conjugated linoleic acid (CLA), were greater than those of cow milk (OrRashid et al, 2008).…”