ABSTRACT:
Maternal colostrum provides the neonate with immunoglobulins, essential for passive immunity. However, storage and handling of colostrum can alter its physical and nutritional characteristics. The aim of this study was to evaluate the effects of three conservation methods on colostrum density, pH, total antioxidant capacity (TAC), protein (PP) and lipid peroxidation (LP). Colostrum samples were collected from 15 Bos indicus cows, and divided into three aliquots for storage using three methods: refrigeration at 4°C, freezing at -20°C, and lyophilization. For each method, four evaluation times were performed: day (d) 5, 10, 15, and 20 for refrigeration and d 15, 30, 45, and 60 for freezing and lyophilization. pH and density analyses were performed at each evaluation time for each method. On d 0 and 15 of storage, TAC, LP, and PP analyses were performed. A generalized linear model, Tukey’s test for means comparisons, and a Pearson correlation analysis were conducted. A decrease in refrigerated colostrum pH was observed on d 15. Density of the lyophilized colostrum decreased, as compared with that of frozen colostrum. Lyophilization exhibited the lower PP values of samples, whereas refrigeration presented the highest values of LP and PP. No differences in colostrum TAC were observed between storage methods. A positive correlation between PP and colostrum density and a negative correlation between colostrum density and TAC were found. It was concluded that both freezing and lyophilization are suitable storage methods for bovine colostrum, as they limit proteins and lipids oxidation, and maintain the TAC of fresh colostrum.
Key words:
antioxidant capacity; bovine; milk; oxidation; storage
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