Foaming properties of milk proteins crosslinked by transglutaminase at different pH values

• Ano de defesa: 2020
• Autor(a) principal: Paes, Laise Trindade
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Micelas; Caseína; Proteína do soro de leite; Espumas; Tecnologia de Produtos de Origem Animal
• Link de acesso: https://locus.ufv.br//handle/123456789/27906

This study investigated the foaming properties of the suspension of milk proteins with a concentration of 40 g/L after treatment with the enzyme transglutaminase (TGase) and acidification at pH 5.1, 5.2, 5.4 and 5.6. Samples without (MP) and with the enzyme (MP-TG) were analyzed to find their viscosity, hydrodynamic diameter, interfacial tension, forming capacity (FC), stability (FS) and foam rheology. The results of hydrodynamic diameter were 256.18 and 245.18 nm for samples MP 5.1 and MP-TG 5.1, respectively, but there was no significant difference between treatments. The viscosity showed higher value in the MP 5.1 samples with 4.093 mPa.s and MP-TG 5.1 with 7.945 mPa.s, showing a significant difference from the other samples. Among all samples, the surface tension showed a maximum and minimum of 44.1 to 45.76 mN / m for samples MP 5.6 and MP 5.2, respectively, but with no significant difference. As for the foaming properties, the foaming capacity (FC) did not show variations in all samples and treatments. The foam stability (FS) was higher at pH 5.1 over the 180 minutes evaluated. When comparing the application of Tgase and pH variation, greater foam stability was observed with a decrease in the pH value. In the rheological analyzes of the foam, the MP-TG 5.4 samples showed a lower elastic limit with 6.27% of the shear stress. On the other hand, samples MP 5.1 and MP-TG 5.1 showed greater resistance to shear deformation, with shear stress above 50% of the measured interval. In conclusion, the decrease in pH allowed greater FS and elasticity of the foam, whereas the treatment with Tgase did not affect these parameters. The response obtained from higher FS to lower pH values allows investigating the foaming properties of new dairy products with pH values that are more acidic than milk. Keywords: Micelles. Caseins. Whey proteins. Foams.