title: Solubility and moisture sorption isotherms of whey-protein-based edible films as influenced by lipid and plasticizer incorporation.
abstract: Plasticized whey-protein and whey-protein emulsion films were produced using sorbitol and glycerol as plasticizers and butterfat and candelilla wax as lipids. Protein, plasticizer, and lipid ratios were optimized to obtain acceptable free-standing flexible films. Water solubility (20 degrees C, 24 h) and moisture sorption isotherms (0.18-0.90 a(w), 25 degrees C) of the films were determined. The experimental moisture sorption isotherm values were fitted using the Guggenheim-Anderson-DeBoer (GAB) model. Solubility and equilibrium moisture contents (EMC) of the films were influenced by plasticizer and lipid incorporation. EMCs of all films increased rapidly at a(w) > or = 0.65. Incorporation of lipids reduced solubilities and EMCs of sorbitol- and glycerol-plasticized films. The effects of plasticizer and lipid type on GAB constants were also determined.
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824-1224, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Kim
authors.forename: Z
authors.initials: Z
authors.lastname: Ustunol
mesh_terms: D000327:Adsorption; D018441:Biofilms / Q000187:drug effects*; D018857:Food Packaging / Q000379:methods*; D006813:Humidity; D008055:Lipids / Q000494:pharmacology*; D008894:Milk Proteins; D008956:Models, Chemical; D010968:Plasticizers / Q000494:pharmacology*; D012995:Solubility; D013816:Thermodynamics; D014867:Water; D000067816:Whey Proteins
chemical_list: D008055:Lipids; D008894:Milk Proteins; D010968:Plasticizers; D000067816:Whey Proteins; D014867:Water