Conjugated linoleic acid contents in cheeses of different compositions during six months of ripenin

Abstract

Lobos-Ortega I., Revilla I., González-Martín M.I., Hernández-Hierro J.M., Vivar-Quintana A., González-Pérez G. (2012): Conjugated linoleic acid contents in cheeses of different compositions during six months of ripening. Czech J. Food Sci., 30: 221-227.The study deals with the effects of the origin of milk (cow, ewe, goat, at different proportions), seasonality, and ripening time on the contents of conjugated linoleic acid (CLA) in 224 samples of cheese. The sum of the cis9, trans11 and trans10, cis12 isomers was determined by GC-FID, after the extraction and methylation of the fatty acids of the samples, observing that the mean amount of CLA was 2.22, 2.72, and 3.54 mg/g of cheese, depending on the proportions of cow's, goat's, or ewe's milks, respectively. The contents in cow's, ewe's, and goat's milk, together with the ripening time and seasonality, were seen to have significant effects (P < 0.05) on the concentration of CLA. The Pearson correlation revealed an inverse correlation between the content of CLA and the % of cow's milk (r = -0.269, P < 0.01) and seasonality (r = -0.290, P < 0.01), and a direct correlation between CLA content and the % of ewe's milk (r = 0.312, P < 0.01) and the month of ripening (r = 0.188, P < 0.01).

Source of Variation of Conjugated-Linoleic-Acid Contents in Dairy Products

“…These values agree with those reported by Pestana et al [15] and Regula et al [21] who reported that pasteurization, depending on its type, causes different changes in the free fatty acid profiles of ewes' milk, which in general has a higher content of CLA as compared to cows' milk [22]. However, Shantha et al [17] and Garcia-Lopez et al [23] reported that the application of heat enhanced the formation of linoleic acid radicals and increased CLA content during the production of natural and processed cheeses.…”

Variation of Fatty Acid Content in Zamorano-Type Ovine Cheese According to the Milk Conjugated Linoleic Acid Content

“…These results were also in agreement with those obtained by [31] for the transfer of C18:1 and C18:2 FA isomers from ewe's milk to Peccorino Toscano cheese. In addition, several authors [12,31,32] found that C18:2 cis-9, trans-11 isomer increased between 10% and 26% on total content of CLA during ripening of different cheeses, which is also compatible with our results. This CLA increase has been associated to hydrogen donors in processed cheese [33].…”

“…The ratio omega-6/omega-3 increased (p<0.05) throughout the ripening in cheeses manufactured from milk with a low CLA content, and remained unchanged for medium CLA contents. These interactions have not been studied up to now and would explain some discrepancies about the CLA evolution over ripening found by several authors [12,31,32,34].…”

Changes in fatty acid profile of feta cheese including conjugated linoleic acid

“…Finally, the kind of milk used in the manufacture of feta cheese may also play a significant role. Early studies have shown that it is difficult to observe the effect of ripening period factor on CLA content of cheeses, because CLA evolves differently depending on the milk type used …”