Abstract
Biofilms are defined as flexible films prepared from biological materials such as proteins and polysaccharides that act as barriers to outside elements. These materials have potential application in medical, pharmaceutical and food area. Their use depends on various parameters such as mechanical properties (strength and flexibility), barrier properties (permeability to water vapor), water solubility, among others. This work aims to characterize biofilms made from pectin and alginate. The films were prepared by casting. This technique consists in preparing a film solution (2 % w/v) followed by the application of it in a holder for solvent evaporation. The manufacturing process of the films consisted of two stages. First the alginate and pectin (1:1) were dissolved in water containing 0.04 g of CaCl2.2H2O/g macromolecule and 0.6 g glycerol/g macromolecule. The second stage (crosslinking complementary) consisted of immersing the films in 50 mL of a solution CaCl2.2H2O and glycerol, both with different concentrations, for 30 minutes. Was evaluated the effects of the plasticizer (glycerol 5, 7 and 10 % v/v) and crosslinking agent (Ca++ 3, 5 and 7 % w/v) on mechanical properties, water solubility, degree of swelling and permeability to water vapor in the biofilms. The films, with an average thickness of 0.07mm, were attractive appearance, acceptable mechanical properties, moisture content around 20 % and water solubility in the range of 32 to 55 %. These films have a degree of swelling around 1 to 3.5 %. The water vapor permeability is moderate and the values are typical of biofilms hydrophilic.
