Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-11-29T17:12:51Z No. of bitstreams: 1 2013 - Renata Silva Cabral de Souza.pdf: 1753830 bytes, checksum: 2dff8752eb3f7974e34f8809d059f126 (MD5) / Made available in DSpace on 2018-11-29T17:12:51Z (GMT). No. of bitstreams: 1 2013 - Renata Silva Cabral de Souza.pdf: 1753830 bytes, checksum: 2dff8752eb3f7974e34f8809d059f126 (MD5) Previous issue date: 2013-05-23 / CAPES / The aim of this study was to evaluate the process of protein concentration in bovine whey proteins by ultrafiltration process and subsequently the protein hydrolysate obtained by enzymatic hydrolysis to produce bioactive peptides with potential antimicrobial and antioxidant activities. For concentration process was used a ceramic ultrafiltration membrane with a molecular range cut-off of 10-20 kDa, transmembrane pressure of 5 bar and, temperature of 30 ?C, 40 ?C and 50 ?C . The optimum temperature condition was at 40 ?C. The Volume Concentrate Factor (VCF) parameter was used as a end-point of the ultrafiltration process and fixed at 2, corresponding on concentrating the initial volume twice, in volume. At the temperature of 40 ?C, VCF had a correspondence on final protein concentration on the concentrated fraction by ultrafiltration and confirmed by Bradford method. Two commercial enzymes were tested Alcalase, Flavourzyme and an equivalent mixture of both 50:50 (w/w) in the hydrolysis reaction. The hydrolysis conditions were determined according to manufacturer instructions and confirmed by other studies: 60 ?C and pH 8 for Alcalase; 50 ?C and pH 7 for Flavourzyme; 50 ?C and pH 8 for enzyme mixture with enzyme / substrate ratio (w / w) 5/100 for all enzymes. The reaction was monitored by pH Stat method. The final Degree of Hydrolysis (DH) achieved was 15%, 52% and 63% for Flavourzyme, Alcalase and enzyme mixture, respectively. Five aliquots were collected along the hydrolysis for each enzyme reaction corresponding to differents DH in order to evaluatethe antioxidant activity by ORAC and ABTS assays with final values between 597- 1092 m? TE (ABTS) and from 1615 to 2920 ?M TE (ORAC) for Flavourzyme; 998-6290 ?M TE (ABTS) and 3092-7567 ?M TE ( ORAC) for Alcalase and finally 913-2678 ?M TE (ABTS) and 2547-5903 ?M TE (ORAC) for the enzyme mixture. The samples from all hydrolysates showed no antimicrobial activity against strains of Salmonella choleraesuis subsp. Enteritidis (ATCC 13076) and Listeria monocytogenes (ATCC 9117). / A proposta do presente trabalho foi avaliar a concentra??o das prote?nas do soro de leite bovino por ultrafiltra??o e posterior obten??o de hidrolisados proteicos deste concentrado via hidr?lise enzim?tica visando obter pept?deos bioativos com potencial atividade antimicrobiana e antioxidante. Para concentra??o das prote?nas do soro foi utilizada membrana cer?mica de ultrafiltra??o com massa molar de corte de 10-20 kDa, press?o aplicada ? membrana de 5 bar, temperaturas testadas (30 ?C, 40 ?C e 50 ?C) . A temperatura ?tima selecionada foi de 40 ?C. O Fator de Concentra??o Volum?trica foi o par?metro utilizado para indicar o final do processo de ultrafiltra??o sendo fixado em duas vezes o volume inicial da alimenta??o. Na temperatura de 40 ?C foi obtida correspond?ncia entre a concentra??o volum?trica e a concentra??o proteica final na fra??o retida pela UF, que tamb?m foi o dobro da encontrada na fra??o alimenta??o, avaliada pelo m?todo de Bradford. Foram testadas duas enzimas comerciais: Alcalase, Flavourzyme e uma mistura equivalente de ambas, na propor??o 50:50 (m/m) na rea??o de hidr?lise. As condi??es de rea??o enzim?tica foram determinadas de acordo com instru??es do fabricante e corroboradas por outros estudos em: 60 ?C, pH 8 para Alcalase; 50 ?C, pH 7 para Flavourzyme; 50 ?C, pH 8 para mistura enzim?tica e rela??o enzima/substrato (g/g) foi de 5/100 para todas as enzimas. A rea??o de hidr?lise foi monitorada pelo m?todo pH Stat. Os Graus de Hidr?lise (GH) finais alcan?ados foram de 15 %, 52 % e 63 % para Flavourzyme, mistura enzim?tica e Alcalase, respectivamente. Foram coletadas cinco al?quotas correspondentes a diferentes GH ao longo da rea??o para cada condi??o enzim?tica utilizada e avaliadas quanto a atividade antioxidante pelos m?todos ABTS e ORAC tendo valores entre 597 a 1092 ?M TE (ABTS) e 1615 a 2920 ?M TE (ORAC) para Flavourzyme, 998 a 6290 ?M TE (ABTS) e 3092 a 7567 ?M TE (ORAC) para Alcalase e por fim, 913 a 2678 ?M TE (ABTS) e 2547 a 5903 ?M TE (ORAC) para a mistura enzim?tica. Nenhuma das amostras de hidrolisado com diferentes GH apresentou atividade antimicrobiana contra cepas de Salmonella choleraesuis subsp. Enteritidis (ATCC 13076) e Listeria monocytogenes (ATCC 9117).