Influence of pH on formation and properties of gellan gels

Autor(es)

Franco Picone, Carolina Siqueira ^[1] ; Cunha, Rosiane Lopes ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Dept Food Engn, Fac Food Engn, BR-13083862 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Carbohydrate Polymers; v. 84, n. 1, p. 662-668, FEB 11 2011.
• Citações Web of Science: 46

Resumo

The effect of pH (3.5, 5.3 and 7.0) on the formation of deacylated gellan gels was studied using oscillatory shear measurements and microcalorimetric trials in heating-cooling cycles at 1 degrees C min(-1). In addition, the mechanical properties and structure of the gels formed at the different pH values were evaluated by uniaxial compression and scanning electron microscopy, respectively. An increase in pH led to an increase in temperature and decrease in enthalpy of the coil-helix transition. These results were attributed to a decreased formation of junction zones at higher pH values due to greater electrostatic repulsion between the gellan molecules. As a consequence, gels formed at neutral pH were more fragile and deformable than acid gels. All the samples showed thermo-reversible rheological behavior, presenting the same rheological properties at 20 degrees C, before and after heating to 90 degrees C. (C) 2010 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 06/02390-7 - Influência da conformação da gelana sobre a gelificação das proteínas do leite
• Beneficiário: Carolina Siqueira Franco Picone
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 04/08517-3 - Propriedades reologicas, termodinamicas e de microestrutura de sistemas formados por polissacarideos e proteinas globulares.
• Beneficiário: Rosiane Lopes da Cunha
• Modalidade de apoio: Auxílio à Pesquisa - Regular