Caracterização proteica e atividade antibacteriana das proteínas do soro do leite caprino

Abstract

Goat's milk is a by-product of great importance for the food and pharmaceutical industry. Proteins have an amino acid sequence in their composition, as well as peptides obtained by the enzymatic hydrolysis process, biological activities such as inhibition of gro wth and bacterial proliferation. Thus, the objective of this work was to characterize as proteins present in the whey of goat milk, to obtain bioactive peptides through hydrolysis with pepsin with pH and time variation and to verify an ant ibacterial activity. The whey of the milk was obtained by means of acid precipitation, centrifuged and lyophilized to perform the analyzes. Protein profile identification was performed by SDS-PAGE, peptide identification was performed by SDSPAGE Tricine, the degree of hydrolysis was evaluated by the OPA method, the MIC of the antibacterial activity was evaluated against the strains of Listeria monocytogenes, Salmonella spp., Staphylococcus aureus and Escherichia coli. The OPA method showed that hydrolysates have bioactivity potential because when applied statistically their degree of hydrolysis is higher than 10%. The minimum inhibitory concentration (MIC) of milk proteins on bacteria when analyzed statistically showed that the best MIC was observed for Gram-positive bacteria, and against Gram-negative strains. The results show that the time of enzymatic reaction was the criterion that most acted on the hydrolysis and the serum of the milk has an inhibitory action against the bacteria tested.