COMPOSITION FACTORS AFFECTING THE WATER-VAPOR PERMEABILITY AND TENSILE PROPERTIES OF HYDROPHILIC FILMS

The water vapor permeability of hydrophilic films was decreased withou t significantly compromising the film's tensile properties through the incorporation of whole milk, sodium caseinate, nonfat dry milk, or wh ey into the film and the proper choice of plasticizer. Sodium alginate films exhibited lower water vapor permeability values than films prep ared using either low or high methoxylated pectin. Sodium lactate was found to be an effective plasticizer, and alginate films containing 50 wt % or more sodium lactate had elongations in excess of 13%. Films p repared with sorbitol as the plasticizer had the best water vapor perm eability values but tended to be stiff and in some cases too brittle f or tensile measurements. Addition of whole milk to film blends effecti vely reduced water vapor permeability values by up to 35%.