title: Study of the physical properties of whey protein isolate and gelatin composite films.
abstract: The relationships between the microstructural and physical properties of the whey protein isolate and gelatin (WPI/gelatin) composite films were investigated in the present work. Through the electrostatic effects at pH 8, WPI and gelatin molecules could form compact aggregates in solution, where a remarkable shrinkage of the gelatin molecules was observed, when the WPI/gelatin mass ratio was close to 50W:50G. FT-IR analysis indicated that hydrogen bonding also involved the aggregation and film-forming process. The melting temperature of the 50W:50G composite film increased by 9 degrees C compared with the single component films. However, this aggregation process also made the film network microstructure discontinuous, and led to a decline of the puncture strength of the film near 50W:50G; in contrast, the deformation and water vapor permeability of the composite films increased with the gelatin content, while the moisture content and solubility did not show significant variations.
authors.affiliation: CAU & ACC Joint-Laboratory of Space Food, Key Laboratory of Functional Dairy Science of Beijing and Ministry of Education, College of Food Science & Nutritional Engineering, China Agricultural University, Haidian, Beijing 100083, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Jiang
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Li
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chai
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Leng
mesh_terms: D005780:Gelatin / Q000737:chemistry*; D006860:Hydrogen Bonding; D008894:Milk Proteins / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D000067816:Whey Proteins; D005780:Gelatin