title: Gelatin-hydroxypropyl methylcellulose water-in-water emulsions as a new bio-based packaging material.
abstract: Gelatin and hydroxypropyl methylcellulose (HPMC) are two incompatible and immiscible biopolymers which cannot form homogeneous composite films using usual methods. In this study, to prevent phase separation, gelatin-HPMC water-in-water (W/W) emulsion was utilized to from transparent composite films by entrapment the HPMC dispersed droplets in gelatin continuous network. The physicochemical and mechanical properties of emulsion-based films containing different amounts (5-30%) of dispersed phase were determined and compared with those of individual polymer-based films. Incorporating HPMC into W/W emulsion-based films had no significant effect on the tensile strength. The flexibility of composite films decreased at HPMC concentrations below 20%. The depletion layer at the droplets interface reduced the diffusion of water vapor molecules because of its hydrophobic nature, so the water vapor permeability remained constant. Increasing the HPMC content in the emulsion films increased the swelling and decreased the transparency. The entrapment of HPMC in continuous gelatin phase decreased its solubility. Therefore, W/W emulsions are capable of holding two incompatible polymers alongside each other within a homogeneous film network without weakening the physical properties.
authors.affiliation: Department of Food Science and Technology, School of Agriculture, Shiraz University, 71441-65186 Shiraz, Iran.
authors.forename: Sara
authors.initials: S
authors.lastname: Esteghlal
authors.affiliation: Department of Food Science and Technology, School of Agriculture, Shiraz University, 71441-65186 Shiraz, Iran.
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Niakosari
authors.affiliation: Department of Food Science and Technology, School of Agriculture, Shiraz University, 71441-65186 Shiraz, Iran. Electronic address: hhosseini@shirazu.ac.ir.
authors.forename: Seyed Mohammad Hashem
authors.initials: SM
authors.lastname: Hosseini
authors.affiliation: Department of Food Science and Technology, School of Agriculture, Shiraz University, 71441-65186 Shiraz, Iran.
authors.forename: Gholam Reza
authors.initials: GR
authors.lastname: Mesbahi
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Shiraz University of Medical Sciences, 7146864685 Shiraz, Iran; Center for Nanotechnology in Drug Delivery, Shiraz University of Medical Sciences, 7146864685 Shiraz, Iran.
authors.forename: Gholam Hossein
authors.initials: GH
authors.lastname: Yousefi
mesh_terms: D004655:Emulsions; D005780:Gelatin / Q000737:chemistry*; D065347:Hypromellose Derivatives / Q000737:chemistry*; D055595:Mechanical Phenomena; D010539:Permeability; D019064:Product Packaging / Q000379:methods*; D012995:Solubility; D013816:Thermodynamics; D014835:Volatilization; D014867:Water / Q000737:chemistry*
chemical_list: D004655:Emulsions; D014867:Water; D065347:Hypromellose Derivatives; D005780:Gelatin
keywords: Emulsion-based film; Incompatibility; Water-in-water emulsion