Comparative study of antioxidant activity in fresh and pasteurized goat milk

Abstract

The enzymatic activity of milk decreases after different heat treatments, because of two effects: the thermal degradation of the antioxidants, and the formation of new species of oxygen after the heating of the milk. The purpose of this study was to determine how the thermal processing of goat milk influences the profile of enzymatic and non-enzymatic antioxidants, caseins concentration and the concentration of malonildialdehyde (MDA, marker of lipids peroxidation). Measurements were conducted on 12 samples of fresh goat milk collected (during) over the period of two weeks. An aliquot of each sample was subjected to pasteurization. Half of all the samples were subjected to freeze-drying. The parameters analyzed for each sample were vitamins A and E; lactoperoxidase and glutathione peroxidase activity; vitamin C; total caseins; MDA. Goat milk pasteurization causes a decrease in the concentration of antioxidant vitamins and antioxidant enzymes activities, correlated with a significant increase in the concentration of malonildyaldehide. In the pasteurized milk, changes were highlighted in the profile of caseins.