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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Extensional and shear viscosity of acidified amaranth starch-sodium caseinate suspensions

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Author(s):
Angela Maria Gozzo [1] ; Rosiane Lopes Cunha [2] ; Florencia Cecília Menegalli [3]
Total Authors: 3
Affiliation:
[1] Universidade Estadual de Campinas. Faculdade de Engenharia de Alimentos. Departamento de Engenharia de Alimentos - Brasil
[2] Universidade Estadual de Campinas. Faculdade de Engenharia de Alimentos. Departamento de Engenharia de Alimentos - Brasil
[3] Universidade Estadual de Campinas. Faculdade de Engenharia de Alimentos. Departamento de Engenharia de Alimentos - Brasil
Total Affiliations: 3
Document type: Journal article
Source: FOOD SCIENCE AND TECHNOLOGY; v. 29, n. 3, p. 587-596, 2009-09-00.
Field of knowledge: Agronomical Sciences - Food Science and Technology
Abstract

Extensional and shear viscosity of acidified amaranth starch-sodium caseinate suspensions were evaluated. Mixed systems of amaranth starch-sodium caseinate acidified with glucone-delta-lactone (GDL) were studied using rheological measurements under biaxial compression and shear. The effects of the acidification rate (slow and fast) and final pH (neutral and isoelectric point of casein) were evaluated considering the interactions between biopolymers and their influence on the rheological parameters. All samples showed shear thinning behavior, but the addition of sodium caseinate in the starch suspensions at neutral pH promoted a negative effect on the apparent viscosity. The acidified samples showed an increase in the complexity of the system due to the formation of a network of starch-casein, but the force required to flow was always higher for samples containing higher concentrations of caseinate. These results show that the protein aggregation and gelation promoted by acidification prevented the microphase separation. The network was stronger in slowly gelled systems due to the formation of a more organized protein network. Although the technique of biaxial compression was not considered adequate to evaluate certain systems, our results showed that it can be a practical and efficient way to measure the rheological behavior. (AU)