Effects of moisture content on structural and dielectric properties of cassava starch films

Autor(es)

Bergo, Paulo ^[1] ; Freitas Moraes, Isabel C. ^[1] ; do Amaral Sobral, Paulo J. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Food Engn, BR-13635900 Pirassununga, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: STARCH-STÄRKE; v. 64, n. 10, p. 835-839, OCT 2012.
• Citações Web of Science: 8

Resumo

In this work, it was evaluated the effect of moisture content on the structural and dielectric properties of cassava starch films by means of Fourier Transform infrared spectroscopy (FTIR), impedancimetric, and gravimetric analysis. The film samples were equilibrated in hermetically sealed desiccators, containing different saturated salts in water in order to promote activity of water between 0.11 and 0.85. The position and amplitude of the peaks in the fingerprint region of the FTIR spectra were changed due to the modifications in the interactions between the polymeric chains and water molecules. These effects may be related to the formation of semi-crystalline regions in the film structure. The dielectric properties of the films were also strongly dependent on the moisture content, showing a non-linear and a linear region, which was attributed to the domain of bound and free water in the film, respectively. The gravimetric analyzes showed the typical sigmoidal behavior, attributed to the way the water interacts with the biopolymer. Finally, the flexibility of the films increased with water content increasing. (AU)

• Processo FAPESP: 05/54688-7 - Estudo das interações entre polióis e biopolímeros em filmes comestíveis por espectroscopia de microondas e de infravermelho
• Beneficiário: Paulo Victor Albuquerque Bergo
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado