Caracterização reológica e estrutural de géis ácidos das proteínas α-lactalbumina, β-lactoglobulina e glicomacropeptídeo

• Ano de defesa: 2011
• Autor(a) principal: Faria, Janaína Teles de
• Orientador(a): Minim, Luis Antonio
• Banca de defesa: Oliveira, Eduardo Basílio de , Ramos, Afonso Mota , Saraiva, Sérgio Henriques
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Ciência e Tecnologia de Alimentos
• Departamento: Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos
• País: BR
• Palavras-chave em Português: Proteínas; Soro de leite; Géis; Reologia
• Palavras-chave em Inglês: Proteins; Whey; Gels; Rheology
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::TECNOLOGIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/2889

The rheological and morphological characteristics of whey protein gels acidified with glucono-δ-lactone were studied. The effect of protein composition (β-Lactoglobulin, α-Lactalbumin and glycomacropeptide concentration) on gelation and rheological properties, using a mixture experimental design, was evaluated. These analyses were complemented by surface morphology analysis of the gels by atomic force microscopy. All mixtures evaluated gelled and, except the highest GMP concentration gel, self supported gels were obtained. Gels made with low proportion of β-Lg presented lower elastic modulus. A higher proportion of α-La increased the gelling time of the mixture and consequently reduced the pH of gelation, while a higher proportion of GMP presented the opposite effect. In the creeprecovery test, there was a decrease of the modified Burgers model parameters with the increased of proportion of α-La and/or GMP in the mixture. The main strain was caused by the retarded elastic deformation. The reversible deformation was higher than irreversible deformation. It was also found that the process of stress relaxation was more pronounced in mixtures with lower proportion of β-Lg. Mixtures with higher proportion of GMP formed gels with rougher surfaces and larger pores, while a higher proportion of α-La resulted in opposite characteristics. With the exception of gels formed by β-Lg and β-Lg/α-La binary mixture with a higher proportion of α-La, micrographs of gels showed particulate networks. Mixed gels were structurally more fragile, and the β-Lg was the main component responsible for the structure and strength of the network.