Flavor and Stability of Pasteurized Milk with Elevated Levels of Conjugated Linoleic Acid and Vaccenic Acid

Abstract

The objectives of this study were to determine if flavor differences between 2% fat pasteurized milks with and without naturally enhanced vaccenic acid (VA) and cis-9, trans-11 conjugated linoleic acids (CLA) levels could be detected over the commercial shelf life of the product and to determine if milk with elevated VA and cis-9, trans-11 CLA levels was more susceptible to development of light-induced oxidative flavor defects. Cows were fed a control diet or the same ration supplemented with 2% soybean oil and 1% fish oil (CLA diet). The milk, standardized to 2% fat, was pasteurized, homogenized, and stored in plastic containers at 4 degrees C. Oxidation was induced by exposing half of the containers to light. Testing was conducted at 1, 7, and 14 d postpasteurization. Average cis-9, trans-11 CLA content of the milks from the control and CLA diet groups was 0.52 and 4.74 g/100 g of fatty acids, respectively (8-fold increase). Average VA content of the milk from the control and CLA diet groups was 1.43 and 12.06 g/100 g of fatty acids, respectively (7.5-fold increase). Together, VA plus CLA represented almost 17% of the total milk fatty acids. There was no effect of light exposure on fatty acid composition initially or over the 14-d storage period. Although VA, cis-9, trans-11 CLA, and degree of unsaturation were significantly elevated in the milk from the CLA diet group, untrained panelists were unable to detect flavor differences initially or over time in 15 of 16 triangle test evaluations. Similarly, sensory results indicated no difference in susceptibility to the development of oxidized off-flavors between the milk from the control and CLA diet groups, even when oxidation was induced by light exposure.

Consumer acceptance of dairy products with a saturated fatty acid–reduced, monounsaturated fatty acid–enriched content

“…In line with other research that evaluated acceptability or sensory characteristics of FA-modified milk Ramaswamy et al, 2001;Kitessa et al, 2004;Lynch et al, 2005), we found that our modified milk had no effect on the mean overall liking, liking of specific modalities, or purchase intent ratings across our consumer population (n = 115). Our trained sensory panel observed some differences in sensory attributes between both modified and control samples and the commercial comparators.…”

“…Some studies have highlighted that FA composition may alter the textural profile of cheese (Palmquist et al, 1993;Chilliard and Ferlay, 2004;Jones et al, 2005;Givens and Shingfield, 2006). Conversely, other studies have shown no effect of PUFA supplementation of the ruminant diet, which predominantly incorporated fish oil, on the sensory characteristics of milk Ramaswamy et al, 2001;Kitessa et al, 2004;Lynch et al, 2005), cheese (Jones et al, 2005;VargasBello-Pérez et al, 2015), or butter ). More research is needed to examine the acceptability of milk and dairy products produced from ruminants that have been subjected to a period of oleic acid-rich supplementation.…”

Increasing pasture intakes enhances polyunsaturated fatty acids and lipophilic antioxidants in plasma and milk of dairy cows fed total mix ration

“…Supplementing diets with oils, crushed seeds or rumen-protected lipids is a common nutritional means for manipulating milk fatty acid composition [12] despite forages often being the major source of fatty acids in the diet [23]. On the other hand, ruminant ingestion of plant oils rich in linoleic acid, including soybean oil [34] and sunflower oil [27], has increased milk fat CLA concentrations effectively.…”

Influence of processing on the fatty acid composition and the content of conjugated linoleic acid in organic and conventional dairy products - a review

“…Jones et al [31] confirm these findings. Lynch et al [51] exposed pasteurised milk rich in CLA (4.74 g·100 g -1 fatty acids) to light. There was no effect of light exposure on fatty acid composition initially or over a 14-d storage period.…”