Film forming capacity of chemically modified corn starches

OLIVIA V. LÓPEZ; MARÍA A. GARCÍA; NOEMÍ E. ZARITZKY

CARBOHYDRATE POLYMERS

Elsevier

Lugar: Amsterdam; Año: 2008 vol. 73 p. 573 - 581

0144-8617

Native starch can be chemically modified to improve its functionality and to expand its uses. Modified starches were characterized andthe rheological behavior of filmogenic suspensions was analyzed. The film forming capacity of different chemical modified corn starcheswas evaluated. Acetylated starch was selected by the characteristics of the resulted films; its optimum concentration was 5% w/w sincetheir films exhibited the lowest water vapor permeability (WVP, 1.26 1010 g/m s Pa). The effect of glycerol as plasticizer on film propertiesdepend on its concentration, being 1.5% w/w those that allows to obtain the lowest WVP value (1.64 1011 g/m s Pa), low filmsolubility in water and a more compact structure than those of unplasticized films. Mechanical behavior of plasticized acetylated starchfilms depends on glycerol concentration, being rigid and brittle the unplasticized ones, ductile those containing 1.5% w/w of glycerol andvery flexible those with a higher plasticizer content. 2008 Elsevier Ltd. All rights reserved.Keywords: Film forming capacity; Chemically modified corn starch films; Plasticizer; Water vapor permeability; Mechanical properties