Identificação do perfil protéico e bioprospecção do soro do leite de cabra concentrado e hidrolisado

• Autor(a) principal: Campos, Maria Isabel Ferreira
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/20073
• topic: Atividade biológica; Caprino; Subproduto; Proteômica; Peptídeos; Biological activity; By-product; Proteomics; Residue; Peptides; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS

Whey is a milk by-product usually discarded by the industry causing pollution to the environment, and therefore alternatives are needed to provide reuse. Thus, the objective of this study was to concentrate goats' milk proteins, quantify them, identify them, evaluate their antibacterial, antiproliferative and antioxidant capacity and finally carry out the hydrolysis of the proteins with the enzymes pepsin and trypsin from a experimental planning of type 2² and to analyze the antioxidant capacity of the best treatments. The whey was obtained by isoelectric precipitation, filtered, dialysed and lyophilized, thus obtaining the concentrated protein. Protein quantification was performed for total proteins and soluble by the method of Kjeldahl and Bradford, respectively. The identification of the proteins was performed by SDS-PAGE electrophoresis and the evaluation of the antibacterial activity was performed by microdilution method against the microorganisms Listeria monocytogenes, Salmonella spp, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli by the method of micro dilution. Antiproliferative activity was performed against the A375 line corresponding to human malignant melanoma cells. Hydrolysates were obtained from the enzymatic hydrolysis of serum proteins using the enzymes pepsin and trypsin at different pH and time values, while the degree of hydrolysis was measured by the Ortofitaldehyde method. Those that presented the best values of degree of hydrolysis were evaluated for the protein profile through Tricine SDS-PAGE electrophoresis and were tested for antioxidant activity by the DPPH and ABTS method and compared to the antioxidant activity of the native protein. The experiments of antibacterial, antiproliferative and antioxidant activity were performed in triplicate and analyzed statistically using the analysis of variance ANOVA and the Dunnet post-test. The results showed the identification in whey from milk of a heterogeneous mixture of proteins, being possible to visualize alpha-lactalbumin, beta-lactoglobulin, lactoferrin, among others. Regarding the antibacterial activity, the minimum inhibitory concentration of the serum of the milk for each microorganism was different, obtaining values that varied in the range of 120 to 30 μg / mL of protein. In relation to the inhibition of the proliferation of cancerous cells the results point the maximum value of 66%, for 24h of exposure. With respect to the hydrolysis of these proteins, from the statistical analysis it was observed that the time and the combination between time and pH were the parameters that had the greatest effect under the degree of hydrolysis of the experiments. The maximum values obtained for hydrolysis of the whey protein are approximately 35%. For these treatments it can be observed that the peptide profile and the antioxidant activity have differences when compared to the native protein, showing that the hydrolysis can generate bioactive peptides capable of performing antioxidant activity. Finally, the results suggest that goat's milk serum is an important functional matrix that has a protein composition of great interest and applicability exerting potential biological activities and thus being able to be reused in order to obtain bioactive peptides.