Study on the oxidative changes in milk lipids, induced by subclinical mastitis and different milking regimes in cows

Abstract

SummaryChipilev, N., G. Kalinova, H. Daskalov & A. Slavova, 2017. Study on the oxidative changes in milk lipids, induced by subclinical mastitis and different milking regimes in cows. Bulg. J. Vet. Med., 20, No 2,[161][162][163][164][165][166][167][168] The fatty acid composition, the amount of free fatty acids and primary and secondary products of oxidation were investigated in relation to quality of raw cows milk produced and stored at a farm with a central milk duct. Raw milk samples were collected from the evening milking, from bulk milk (evening and morning milkings) and from animals with signs of subclinical mastitis. It was established that bulk milk and the milk from cows with subclinical mastitis contained more short-and mediumchain saturated fatty acids (С4:0 to С16:0) and less long-chain unsaturated fatty acids (С18:1 and С18:2), mainly because of the altered amount of oleic and linoleic acids. In mastitic milk, apart the increased somatic cell counts, increased values of free fatty acids (FFA), peroxide value and malondialdehyde (MDA) concentrations were found out, while total phospholipids were decreased. Similar tendencies in FFA, peroxide value and MDA were established in bulk milk samples. The main reason for these changes were oxidative changes in bulk milk in the milk collection tank.

Electrochemical Basis for Re-evaluating Antioxidant Effect of Redox Substances in Foodstuffs

“…Redox systems in milk are presented by the leukoriboflavin/riboflavin couple, cysteine/cystine couple, and ascorbic acid/dehydroascorbic acid couple . Chipilev et al demonstrated that redox substances of milk are vital inhibitors of undesirable oxidative changes. The formation of the “oxidized” flavor of milk was shown to be a result of the action of “antioxidative” and “prooxidative” factors …”

“…The formation of the “oxidized” flavor of milk was shown to be a result of the action of “antioxidative” and “prooxidative” factors Adding pro-oxidants (redox mechanism) resulted in the reduction of the total antioxidant capacity of milk and an increase in products of oxidation . Therefore, reduction processes in unpasteurized milk should be considered as quality improving factors.…”

“…However, the information with respect to antioxidants with the redox mechanism is very controversial and limited, despite the importance of redox reactions in cells of living organisms , as well as in food systems. Antioxidants with a redox mechanism prevent color and ascorbic acid, degradation in foodstuffs of plant origin. − Redox substances were shown to be important in providing a positive effect on milk quality . The effect of redox reactions on color, flavor, texture, and shelf life of fermented food products was demonstrated by Hansen .…”

“…31−34 Redox substances were shown to be important in providing a positive effect on milk quality. 35 The effect of redox reactions on color, flavor, texture, and shelf life of fermented food products was demonstrated by Hansen. 28 The positive and negative effects of different polyphenols on the quality of different products were previously reported and are still relevant.…”

Influence of reactive oxygen and nitrogen species on udder health and milk quality

“…Verma;Ambatipudi (2016) showed that modified gas chromatography and mass spectrometry might be effective for determining free fatty acid, polyunsaturated fatty acid, and prostaglandin levels in the mastitis-affected cow milk. Chipilev et al (2017) reported chromatographic and spectrophotometric methods for the detection of fatty acid peroxidation in bovine milk.…”