Factors affecting the conjugated linoleic acid content of Cheddar cheese

The effects of package type (cans and nylon vacuum pouches), milling pH (5.5, 5.7, and 5.9), additives [butylated hydroxyanisole (BHA), tyrosine, and lysine], and aging (0, 1, 3, and 6 months) on the conjugated linoleic acid (CLA) content of Cheddar cheese was determined. Fatty acid distributions and CLA, moisture, protein, lipid, and titratable acidity contents in raw milk and aged cheeses were determined. The CLA content in canned cheese (3.03 mg/g lipid) was significantly higher than in a vacuum pouch packed cheese (2.70 mg/g lipid) after 6 months of aging. Milling pHs of 5.5 and 5.9 and the addition of BHA, tyrosine,and lysine resulted in significantly lower CLA contents in cheeses aged for 6 months than the control. Multiple linear regression showed that lipid and protein contents contributed to CLA content positively. The content of oleic acid contributed significantly to the relationship between CLA and fatty acids.