Obtenção e caracterização de amido de mandioca (Manihot esculenta Crantz) modificado com ácido tartárico

Detalhes bibliográficos
Ano de defesa: 2015
Autor(a) principal: Viell, Franciele Leila Giopato
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Tecnológica Federal do Paraná
Campo Mourao
Medianeira
Programa de Pós-Graduação em Tecnologia de Alimentos
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://repositorio.utfpr.edu.br/jspui/handle/1/1225
Resumo: The chemical modification of native starch cause structural changes in the polymer molecule affecting their physic-chemical properties which make them suitable for various industrial uses. Tartaric acid is an organic dicarboxylic acid which can chemically modify the starch structure and its use is allowed in foods. In this study, the tapioca starch was modified with tartaric acid and the effect of acid concentration (4.5 to 8.0 g.100g-1) and the reaction pH (5.0 to 8.0) on the properties starch were evaluated using a 22 face-centered central composite design. The physico-chemical properties, functional, and pasting properties were determined. The infrared spectra Fourier transform (FT-IR) and the morphology of granules by scanning electron microscopy (SEM) was also evaluated. The modification reduced the intrinsic viscosity and the amylose contents with the increase of the acid concentration and decrease of pH. At pH 5.0, there was a higher percentage of mono tartarate ester and higher swelling and solubility of starches were observed. At pH 6.5 and 8.0, the modification caused a reduction in the swelling and solubility, increased resistance to freeze-thaw and improvement in the pasting properties (increased thermal and mechanical resistance). FT-IR confirmed qualitatively the esterification of starch by the appearance of bands attached to ester groups in the tests performed at pH 5.0. The modification did not cause obvious changes in the external morphology of the starch granules as observed by MEV. It was possible to conclude that the effect of acid concentration on the properties of the starch was less than the effect of pH where lower pH values favor the esterification of starch and higher pH values favor the crosslinked.