Fatty acid profile of Canadian dairy products with special attention to the trans-octadecenoic acid and conjugated linoleic acid isomers.
Current scientific evidence indicates that consumption of industrial trans fatty acids (TFA) produced via partial hydrogenation of vegetable oils increases the risk of coronary heart disease. However, some studies have suggested that ruminant TFA, especially vaccenic acid (VA or 11t-18:1) and rumenic acid (RA or 9c,11t-18:2), which is a conjugated linoleic acid (CLA) isomer, may have potential beneficial health effects for humans. To date, no concerted effort has been made to provide detailed isomer composition of ruminant TFA and CLA of Canadian dairy products, information that is required to properly assess their nutritional impacts. To this end, we analyzed the fatty acid profile of popular brands of commercial cheese (n = 17), butter (n = 12), milk (n = 8), and cream (n = 4) sold in retail stores in Ottawa, Canada, in 2006-2007 by silver nitrate thin-layer chromatography and gas liquid chromatography. The average total TFA content of cheese, butter, milk, and cream samples were 5.6, 5.8, 5.8, and 5.5% of total fatty acids, respectively. VA was the major trans-octadecenoic acid (18:1) isomer in all the Canadian dairy samples with average levels of (as % total trans-18:1) 33.9% in cheese, 35.6% in butter, 31.0% milk, and 30.1% in cream. The different dairy products contained very similar levels of CLA, which ranged from 0.5 to 0.9% of total fat. RA was the major CLA isomer of all the dairy products, accounting for 82.4-83.2% of total CLA. There were no significant differences (P > 0.05) in the fatty acid profile between the 4 different dairy groups, which suggests lack of processing effects on the fatty acid profile of dairy fat.
Mendis
Sanjaya
S
Health Canada, Nutrition Research Division, Food Directorate, Health Products and Food Branch, 251 Sir Frederick Banting Driveway, Ottawa, ON, Canada.
Cruz-Hernandez
Cristina
C
Ratnayake
Walisundera M N
WM
D000818:Animals; D002079:Butter / Q000032:analysis; D002170:Canada; D002417:Cattle; D002611:Cheese / Q000032:analysis; D002849:Chromatography, Gas; D003611:Dairy Products / Q000032:analysis*; D004952:Esters / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D007202:Indicators and Reagents; D007536:Isomerism; D019787:Linoleic Acid / Q000032:analysis*; D008892:Milk / Q000737:chemistry; D012835:Silver Nitrate; D013229:Stearic Acids / Q000032:analysis*
C114874:5-octadecenoic acid; D004952:Esters; D005227:Fatty Acids; D007202:Indicators and Reagents; D013229:Stearic Acids; D002079:Butter; D012835:Silver Nitrate; D019787:Linoleic Acid