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Oxidative stability of milk influenced by fatty acids, antioxidants, and copper derived from feed.

Abstract

Differences in the oxidative stability of milk from cows fed grass-clover silage or hay were examined in relation to fatty acid composition and contents of antioxidants and copper in the milk. The oxidation processes were induced by exposing the milk to fluorescent light. Protein oxidation was measured as an accumulation of dityrosine, whereas lipid oxidation was measured as an accumulation of lipid hydroperoxides as the primary oxidation product, and as the secondary oxidation products, pentanal, hexanal, and heptanal. No differences were found in the protein oxidation of the 2 types of milk measured as accumulation of dityrosine, but there was an increased accumulation of lipid hydroperoxides and hexanal in milk from cows fed grass-clover silage, compared with milk from cows fed hay. The higher degree of lipid oxidation in milk from cows fed grass-clover silage could not be explained from the concentration of alpha-tocopherol, carotenoids, uric acid, and copper in the milk. However, it was thought to be highly influenced by the significantly higher concentration of linolenic acid present in milk from cows fed grass-clover silage. A larger part of alpha-tocopherol and beta-carotene was transferred from the feed to the milk when cows were fed grass-clover silage than when cows were fed hay as roughage. The significantly higher concentration of polyunsaturated fatty acids in milk from cows fed grass-clover silage may be important for the better transfer of alpha-tocopherol from the feed to the milk. Other circumstances, as the different conditions in the rumen may also play a role, due to the different types of roughages and their digestibility, or be related to the mechanisms during milk production for the higher yielding cows fed grass-clover silage.

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  • Publisher Full Text
  • Authors+Show Affiliations

    ,

    Danish Institute of Agricultural Sciences, Department of Food Science, Research Centre Foulum, P.O. Box 50, 8830 Tjele, Denmark.

    , , ,

    Source

    Journal of dairy science 89:6 2006 Jun pg 1970-80

    MeSH

    Aldehydes
    Animal Feed
    Animals
    Antioxidants
    Cattle
    Copper
    Fatty Acids
    Female
    Food Preservation
    Gas Chromatography-Mass Spectrometry
    Light
    Lipid Peroxidation
    Lipid Peroxides
    Milk
    Oxidation-Reduction
    Riboflavin
    Time Factors
    Tyrosine
    Volatilization
    alpha-Tocopherol
    beta Carotene

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    16702260

    Citation

    TY - JOUR T1 - Oxidative stability of milk influenced by fatty acids, antioxidants, and copper derived from feed. AU - Havemose,M S, AU - Weisbjerg,M R, AU - Bredie,W L P, AU - Poulsen,H D, AU - Nielsen,J H, PY - 2006/5/17/pubmed PY - 2006/8/25/medline PY - 2006/5/17/entrez SP - 1970 EP - 80 JF - Journal of dairy science JO - J. Dairy Sci. VL - 89 IS - 6 N2 - Differences in the oxidative stability of milk from cows fed grass-clover silage or hay were examined in relation to fatty acid composition and contents of antioxidants and copper in the milk. The oxidation processes were induced by exposing the milk to fluorescent light. Protein oxidation was measured as an accumulation of dityrosine, whereas lipid oxidation was measured as an accumulation of lipid hydroperoxides as the primary oxidation product, and as the secondary oxidation products, pentanal, hexanal, and heptanal. No differences were found in the protein oxidation of the 2 types of milk measured as accumulation of dityrosine, but there was an increased accumulation of lipid hydroperoxides and hexanal in milk from cows fed grass-clover silage, compared with milk from cows fed hay. The higher degree of lipid oxidation in milk from cows fed grass-clover silage could not be explained from the concentration of alpha-tocopherol, carotenoids, uric acid, and copper in the milk. However, it was thought to be highly influenced by the significantly higher concentration of linolenic acid present in milk from cows fed grass-clover silage. A larger part of alpha-tocopherol and beta-carotene was transferred from the feed to the milk when cows were fed grass-clover silage than when cows were fed hay as roughage. The significantly higher concentration of polyunsaturated fatty acids in milk from cows fed grass-clover silage may be important for the better transfer of alpha-tocopherol from the feed to the milk. Other circumstances, as the different conditions in the rumen may also play a role, due to the different types of roughages and their digestibility, or be related to the mechanisms during milk production for the higher yielding cows fed grass-clover silage. SN - 1525-3198 UR - https://www.unboundmedicine.com/medline/citation/16702260/Oxidative_stability_of_milk_influenced_by_fatty_acids_antioxidants_and_copper_derived_from_feed_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-0302(06)72264-0 ER -