Changes of protein fractions in milk obtained from cows with mastitis caused by Staphylococcus aureus. Preliminary communication
1990
Kostyra, E. (Akademia Rolniczo-Techniczna, Olsztyn (Poland). Katedra Poloznictwa)
The tested milk was derived from two cows of the black-white lowland breed aged 5 years in the second stage of lactation. Proteins soluble and insoluble at pH 4.6 were characterized by means of starch-urea and polyacrylamide gel electrophoresis. The solution of nitrogen compound reacting with ninhydrin and soluble at pH 4.6 was separated by gel filtration, thin-layer chromatography and high-voltage paper electrophoresis. In the milk of the infected cows degradation of alpha sub (s), beta and cappa casein and increased content of gamma immunoglobulin were observed. In whey proteins a rise of serum albumin content and decrease of beta-lactoglobulin and alpha-lactoalbumin were observed. In the solution after precipitation of casein at pH 4.6 in the milk of the infected cow a greater number of fractions reacting with ninhydrin was found. The observed range of degradation changes in milk protein of the infected cow (S. aureus) suggests that it has a negative effect on the technological, nutritional and hygienic value of milk
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