Autoxidation in milk rich in linoleic acid I. An objective method for measuring autoxidation and evaluating antioxidants

Sidhu, G. S.; Brown, Melissa A.; Johnson, A. R.

doi:10.1017/s0022029900015211

Cited by 24 publications

(7 citation statements)

References 22 publications

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“…The consistent and highly significant increase in concentrations of PUFA in milk from cows fed RCS provides an explanation for the reduced oxidative stability of milk. Many earlier studies have shown that increasing concentrations of unsaturated fatty acids in milk, particularly of PUFA C 18:2 and C 18:3 , will increase the susceptibility of milk to oxidation (e.g., Sidhu et al, 1975;Granelli et al, 1998;Timmons et al, 2001).…”

Section: Oxidative Stability Of Milkmentioning

confidence: 99%

Effects of Silage Species and Supplemental Vitamin E on the Oxidative Stability of Milk

Al-Mabruk

Beck

Dewhurst

2004

Journal of Dairy Science

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Two experiments were conducted to study the effects of feeding legume silages and providing supplemental vitamin E in concentrates on the oxidative stability of milk. In experiment 1, six multiparous Holstein-Friesian cows were offered 1 of 6 silage treatments in a cyclical changeover-design experiment, with four 4wk periods. The silages were grass, red clover, white clover, alfalfa, grass and red clover mixture (50:50 on a DM basis), and grass and white clover mixture (50:50 on a DM basis). In experiment 2, 8 cows were used in a changeover-design experiment with three 4-wk periods. The 4 treatments were a factorial combination of forages (grass silage or red clover silage) and supplemental vitamin E in the form of all-rac-α-tocopheryl acetate (29 or 290 IU/kg of DM in the concentrate). All forages were offered ad libitum and a flat rate of concentrates (8 kg/d) was fed in both experiments. Red clover silage led to significantly higher forage intakes, milk yields, and milk protein percentage in experiment 2, which was in agreement with results from experiment 1. There was no effect of vitamin E on feed intake, milk production, or milk fat and protein percentage. Red clover silage also led to significant changes in milk fatty acid profiles, particularly increased levels of polyunsaturated fatty acids. Milk samples were stored at 4°C and 20°C and analyzed for α-tocopherol and thiobarbituric acid reactive substances at intervals to determine oxidative stability. Diets based on red clover and alfalfa silages were associated with more rapid loss of α-tocopherol and increased production of thiobarbituric acid reactive substances during the storage of milk in comparison with diets based on grass silage. The increased oxidative deterioration of milk produced from cows fed red clover silage was avoided by vitamin E supplementation.

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Section: Oxidative Stability Of Milkmentioning

confidence: 99%

Effects of Silage Species and Supplemental Vitamin E on the Oxidative Stability of Milk

Al-Mabruk

Beck

Dewhurst

2004

Journal of Dairy Science

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“…A potential downside of such a breeding strategy is that unsaturated milk FA are more prone to oxidize (Sidhu et al, 1975;Barrefors et al, 1995;Granelli et al, 1998;Timmons et al, 2001), giving a carbon, metal, talcum, or fishy flavor to the milk (Shipe et al, 1978). This off-flavor results from volatile compounds that accumulate in the milk through the oxidation of the double bonds between the carbon atoms in unsatu-4611 rated FA.…”

Section: Introductionmentioning

confidence: 99%

Association of DGAT1 genotype, fatty acid composition, and concentration of copper in milk with spontaneous oxidized flavor

Juhlin

Fikse

Picková

et al. 2012

Journal of Dairy Science

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In 136 cows with altogether 969 milk samples, we investigated the effect of the acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) K232A polymorphism on milk fatty acid (FA) composition and how, in combination with copper concentration in milk, this influences the occurrence of spontaneous oxidized flavor. All milk samples were analyzed for concentrations of copper and individual FA and subjected to sensory analysis by trained judges. We found an effect of DGAT1 genotype on FA composition where mainly the long-chain FA were affected. The 232A allele was associated with larger proportions of the C18:2 cis-9,trans-11 conjugated linoleic acid and lower proportions of C16:0 FA. Milk concentrations of unsaturated FA and copper showed strong and unfavorable associations with spontaneous oxidized flavor (SOF) development. The interaction between FA and copper indicates that SOF will not develop as easily in milk with high copper content unless the substrate is available (i.e., in addition to the previously shown effect of copper in milk, unsaturated FA are required for the process of oxidation to progress). We observed a marked effect of the DGAT1 genotype on SOF development where the A allele was associated with a higher risk of SOF. Moreover, our results suggest that the effects of the FA C18:3 n-3 and of the polyunsaturated index on SOF development are beyond the effect of the DGAT1 genotype. Breed had an effect on FA composition but not on SOF development. Our results imply that copper, FA composition, and DGAT1 genotype are risk factors for SOF and considerations to these factors might be necessary in future breeding decisions.

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“…Studies have shown that the susceptibility of milk to develop SOF increases with elevated concentration of long chain unsaturated milk fatty acids (Sidhu et al 1975; Granelli et al 1998; Timmons et al 2001). However, because intake of polyunsaturated fatty acids (PUFA) have been associated with improved blood cholesterol profile in humans significant efforts have been made during the last decade to increase PUFA in cow's milk fat.…”

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confidence: 99%

Relative impact of α-tocopherol, copper and fatty acid composition on the occurrence of oxidized milk flavour

Juhlin

Fikse

Lundén

et al. 2010

Journal of Dairy Research

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The oxidative process in milk fat, resulting in spontaneous oxidized off-flavour (SOF), is commonly assumed to depend on contents of pro- and antioxidants in milk and availability of fatty acids acting as their substrate. An important antioxidant in milk is alpha-tocopherol whereas the most potent prooxidant is the metal ion copper. The separate effects of alpha-tocopherol, copper, and milk fatty acid profile, and their combined effect on SOF development were examined in milk from 44 multiparous cows fed different roughage types and different amounts of dietary, unsaturated fat. A clear association between concentrations of copper and poly-unsaturated fatty acids in milk and the risk for developing SOF was found. Heritability estimates suggest that occurrence of SOF is partly under genetic control which indicates that milk quality may be compromised if breeding bulls are selected that carry genotypes predisposing for milk prone to develop SOF.

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Autoxidation in milk rich in linoleic acid I. An objective method for measuring autoxidation and evaluating antioxidants

Cited by 24 publications

References 22 publications

Effects of Silage Species and Supplemental Vitamin E on the Oxidative Stability of Milk

Effects of Silage Species and Supplemental Vitamin E on the Oxidative Stability of Milk

Association of DGAT1 genotype, fatty acid composition, and concentration of copper in milk with spontaneous oxidized flavor

Relative impact of α-tocopherol, copper and fatty acid composition on the occurrence of oxidized milk flavour

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