Microstructural Characterization of Plasticized Starch-Based Films.

GARCIA, M.A.; MARTINO, M.N.; ZARITZKY, N.E.

STARCH/STARKE

Año: 2000 vol. 52 p. 118 - 124

0038-9056

Edible films were developed using different starch sources (corn starch and amylomaize). Starch suspensions were cold gelatinized with NaOH; either glycerol or sorbitol were used as plasticizer. Films were characterized by Differential Scanning Calorimetry (DSC), X ray diffraction, Scanning Electron Microscopy (SEM) and gas (CO2 and O2) permeabilities. SEM observations showed that plasticizer addition was necessary for film integrity. The evaluation of film formation by DSC indicated that cold gelatinization was the main factor of thermal transitions. Film crystallinity was analyzed by DSC and X ray diffraction during storage. For all tested formulations, film crystallinity increased while gas permeability decreased during storage. Films with glycerol or sorbitol showed a lower crystalline/amorphous ratio by X ray diffraction and DSC compared to unplasticized films. Amylomaize films with higher crystalline/amorphous ratio gave lower gas permeabilities than corn starch; films with sorbitol showed lower permeability values than glycerol ones.