title: 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 Delta9-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.
authors.affiliation: Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
authors.forename: Mamun M
authors.initials: MM
authors.lastname: Or-Rashid
authors.forename: Nicholas E
authors.initials: NE
authors.lastname: Odongo
authors.forename: Bhishma
authors.initials: B
authors.lastname: Subedi
authors.forename: Pralhad
authors.initials: P
authors.lastname: Karki
authors.forename: Brian W
authors.initials: BW
authors.lastname: McBride
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D002611:Cheese / Q000032:analysis*; D002849:Chromatography, Gas; D004951:Esterification; D044243:Linoleic Acids, Conjugated / Q000032:analysis*; D008892:Milk / Q000737:chemistry; D009390:Nepal; D006109:Poaceae; D044242:Trans Fatty Acids / Q000032:analysis*
chemical_list: D044243:Linoleic Acids, Conjugated; D044242:Trans Fatty Acids