Effects of Microfiltration and Storage Time on Cholesterol, Cis-9, Trans-11 and Trans-10, Cis-12 Conjugated Linoleic Acid Levels, and Fatty Acid Compositions in Pasteurized Milk

The effects of microfiltration and storage time on the contents of cholesterols, conjugated linoleic acids, particle size distributions, and fatty acid profiles in pasteurized milk were investigated over 7 days. After microfiltration, the cholesterol (except for day 7) and trans-10, cis-12 conjugated linoleic acids did not change in microfiltered and pasteurized milk and in pasteurized milk. Compared with pasteurized milk, the cis-9, trans-11 conjugated linoleic acids, and -6/-3 ratio decreased by 43 and 12%, while d(32), d(43), C18:3n-3, and C20:5n-3 increased by 52-57, 70, 3.2-5.8, and 4.8-2.6% in microfiltered and pasteurized milk, respectively. The contents of cis-9, trans-11 conjugated linoleic acids, and cholesterols were higher on day 7 than on day 0, while the -6/-3 ratio and C22:6n-3 showed the opposite tendencies. Storage time did not affect d(32) (except for microfiltered and pasteurized milk) and d(43). These highlighted that microfiltration has the potential to retain -3 fatty acids, decreased the -6/-3 ratio and maintain the stability of microfiltered and pasteurized milk shelf life.