PLASTICIZED WHEY-PROTEIN EDIBLE FILMS - WATER-VAPOR PERMEABILITY PROPERTIES

Heat treatment, protein concentration, and pH effects on water vapor p ermeability (WVP) of plasticized whey protein films were examined. The best film formation conditions were neutral pH, aqueous 10% (w/w) pro tein solutions heated for 30 min at 90 degrees C. Isoelectric point ad justment of whey protein with calcium ascorbate buffer increased WVP w ith increasing buffer concentration. The importance of vacuum applicat ion to minimize film pore size was identified using scanning electron microscopy. Polyethylene glycol, glycerol and sorbitol plasticizer con centration affected film WW. Determining the effects of relative humid ity on WVP for plasticized whey protein films enabled prediction of fi lm behavior under any water vapor partial pressure gradient.