INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
artículos
Título:
Characterization of chitosan/caseinate films
Autor/es:
M. PEREDA; M. I. ARANGUREN; N. E. MARCOVICH
Revista:
JOURNAL OF APPLIED POLYMER SCIENCE
Editorial:
Wiley
Referencias:
Año: 2008 vol. 107 p. 1080 - 1090
ISSN:
0021-8995
Resumen:
ABSTRACT: Films made from sodium caseinate and/or
chitosan, using glycerol as plasticizer, were prepared by
casting from aqueous solutions. Films cryo-fractured surfaces
were examined by SEM. FTIR spectra of the chitosan/
caseinate films showed an increase in the intensity of the
amide band, corresponding to the strong interactions
developed by the polyelectrolytic complexation of both
components. Addition of 28 wt% of glycerol to caseinate
films, conditioned at 50% relative humidity (RH), reduced
the modulus from 2908 to 250.9 MPa, while the ultimate
elongation increased from 4 to 63.2%. Increment to 80%
RH further reduced the modulus down to 52.8 MPa.
Similar results were found for the glycerol plasticization of
chitosan films. The complex films showed a moderate
improvement of the tensile strength (19.6 MPa) and an
increase of the impact strength (35.6 GPa) with respect to
those corresponding of chitosan films (17 MPa and 26.6
GPa, respectively). These properties were markedly
improved with respect to those of caseinate (6.2 MPa and
13.4 GPa, respectively). The interactions developed
between the cationic polymer chitosan, and the Na-caseinate
carboxyl groups, lead to polyelectrolyte complexation
in forming the film, which is proposed as the reason for
improvement with respect to caseinate or chitosan
films.
Key words: caseinate; chitosan; glycerol; edible films