EFFECT OF GLYCEROL CONTENT AND pH VALUE OF FILM-FORMING SOLUTION ON THE FUNCTIONAL PROPERTIES OF PROTEIN-BASED EDIBLE FILMS

The work is concerned with the effects of glycerol content and pH value of film for-ming solution on the functional properties of protein-based films. The films were pro-duced of chicken breast proteins, dissolved under either acidic (pH 3) or alkaline (pH 11) conditions, with different concentrations of glycerol (35%, 50 % and 65 % w/w of protein content). Glycerol content affected significantly mechanical properties, water vapor per-meability, color at pH 3 and film solubility (p<0.05). The pH value had significant influ-ence on light transmission, color, transparency and film solubility (p<0.05). Considering the results of mechanical properties and film solubility, the obtained films are in the acceptable range for the use as a packaging material. It was estimated that water vapor permeability, color, light transmission and transparency need to be improved for the application