Consumer Acceptability of Conjugated Linoleic Acid-Enriched Milk and Cheddar Cheese from Cows Grazing on Pasture

Abstract

Two experiments were conducted to study the consumer acceptability attributes of conjugated linoleic acid (CLA)-enriched milk and cheese from cows grazing on pasture. In experiment 1, 15 cows were fed either a diet containing 51% alfalfa hay plus corn silage and 49% concentrate [total mixed ration (TMR)], were grazed on pasture, or were grazed on pasture and received 3.2 kg/d of a grain mix. The grain mix contained 75% full-fat extruded soybeans (FFES), 10% corn, 10% beet pulp, and 5% molasses. During the final 3 wk of the 6-wk experiment, milk was evaluated for sensory attributes. In experiment 2, 18 cows were fed similar diets as in experiment 1, except replacing the group of cows grazed on pasture and receiving the grain mix was a group of cows grazed on pasture and receiving 2.5 kg/d per cow of the FFES; Cheddar cheese was manufactured from milk. Average CLA contents (g/100 g of fatty acid methyl esters) were 0.52, 1.63, and 1.69 in milk and 0.47, 1.47, and 1.46 in cheese from cows fed a TMR, grazed on pasture, and grazed on pasture and fed the grain mix, respectively. An open and trained panel evaluated CLA-enriched milk for mouth-feel, color, flavor, and quality and evaluated cheese for color, flavor, texture, and quality. Open and trained panel evaluations of milk and cheese showed no differences among treatments for any of the attributes, except that the trained panel detected a more barny flavor in milk from cows grazing pasture compared with milk from cows fed the TMR only. Results suggest that consumer acceptability attributes of CLA-enriched milk and cheese from cows grazing pasture is similar to those of milk and cheese with low levels of CLA.

Effect of extruded whole soybean dietary concentrate on conjugated linoleic acid concentration in milk in Jersey cows under pasture conditions

“…As in our study, Khanal et al (2005) did not found effects of a mixed supplement containing 2.4 kg d -1 of extruded soybean on CLA concentration in the milk of Holstein cows on pasture (1.63 and 1.69% of total FA for groups fed on pasture alone and pasture + supplement mixed with extruded soybean, respectively; these values include the cis-9, trans-11 isomer). The values obtained by these authors are somewhat higher than those found herein for the three CLA isomers together.…”

“…However, contradictory results has been found on the effects of soybean supplementation and CLA content in milk on feeding systems based on fresh forage. Some studies (Bartolozzo et al, 2003;Khanal et al, 2005) did not found effects on milk CLA concentration in dairy cows, while others (Lawless et al, 1998;Paradis et al, 2008) observed an increase in the CLA using dairy and beef cattle.…”

“…Several nutritional studies have been addressed to increase CLA content in animal products and to improve their nutritional properties. For instance, it has been reported that fresh forage and oil-rich feeds increase CLA concentration (Khanal et al, 2005;Dewhurst et al, 2006). Soybean is widely used in total mixed ration (TMR) in different proportions, and it has been observed that seed treatment (roasting or extrusion) results in a higher increase on CLA content than that observed with intact seed (Chouinard et al, 2001).…”

Concentration of trans-vaccenic and rumenic acids in the milk from grazing cows supplemented with palm oil, rice bran or whole cottonseed

“…Differences between diets CS and RB are not easy to explain since intakes of precursors of these two FA in milk were similar. Some authors suggest that whole seeds may produce a lower concentration of TVA and RU in milk lipid than processed seed, due to a lower ruminal availability of unsaturated FA in whole seeds, where FA are protected from ruminal biohydrogenation, resulting in a higher concentration of milk unsaturated FA (Dhiman et al, 2000;Khanal et al, 2005;Paradis et al, 2008). However, CS had lower concentrations of LI and LN acids and higher concentrations of stearic acid in milk lipids than RB, suggesting a more extensive biohydrogenation in the CS diet.…”

Conjugated linoleic acid content in milk of Chilean Black Friesian cows under pasture conditions and supplemented with canola seed (Brassica napus) concentrate

“…The content of CLA in fat from ruminant-derived foods is dependent on the ruminal production of both CLA, trans-vaccenic acid (TVA), and on the tissue activity of Δ 9 -desaturase. For instance, it has been reported that fresh forage (Khanal et al, 2005;Dewhurst et al, 2006;Butler et al, 2008; Conjugated linoleic acid content in milk of Chilean Black Friesian cows under pasture conditions and supplemented with canola seed (Brassica napus) concentrate Rego et al, 2008) and diets supplemented with plant oils, high in linoleic acid Stanton et al, 2003) increase CLA concentration in milk fat. Within the seeds of oilseeds, rapeseed (Brassica napus) has been used in TMR (total mixed ration) diets in dairy cows (Bayourthe et al, 2000, Chouinard et al, 2001Ward et al, 2002;Chichlowski et al, 2005;Chen et al, 2008;Neves et al, 2009;Lerch et al, 2012b).…”