Mechanical and Barrier Properties of Composite Hydrocolloid Filmsp

PINOTTI, A; GARCÍA. M.A.; MARTINO, M; ZARITZKY, N

Zurich, Suiza

Simposio; 3RD International Symposium on Food Rheology and Structure ISFRS; 2003

The objectives of the present work were to characterize: i) rheological and surface tension properties of the hydrocolloid suspensions and ii) barrier and mechanical properties of the composite films. Suspensions of 1 and 2 % chitosan (CH) and 1% methylcellulose (MC) were mixed in different ratios. All suspensions showed pseudoplastic behavior; power law model satisfactory fitted experimental data. Water vapor permeability values ranged between 7.5 and 9.0 ´ 10-11 g m-1 s-1 Pa-1 for CH and MC films; intermediate values were obtained for the composite films. With regard to mechanical properties, chitosan films showed rigid and brittle characteristics which were evidenced by high elastic modulus and small elongation at break. Film flexibility increased with increasing MC content, the higher elongation at break and lower elastic modulus of composite films.