Physical assessment of composite biodegradable films manufactured using whey protein isolate, gelatin and sodium alginate

• Published in: Journal of food engineering 2010, Vol.96 (2), p.199-207
• Main Authors: Wang, Lizhe, Auty, Mark A.E., Kerry, Joe P.
• Format: Article
• Language: English
• Subjects: alginate gels; alginates; biodegradability; Biodegradable films; biodegradable products; Biological and medical sciences; biopolymers; deformation; films (materials); Food engineering; Food industries; food packaging; Fundamental and applied biological sciences. Psychology; Gelatin; General aspects; mechanical properties; Milk and cheese industries. Ice creams; oxygen; packaging materials; permeability; protein isolates; scanning electron microscopy; Sodium alginate; tensile strength; water vapor; whey protein; Whey protein isolate
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2009.07.025

Composite films were manufactured using whey protein isolate (WPI), gelatin (G) and sodium alginate (SA) using a simplex centroid design. Tensile strength (TS), puncture strength (PT), percentage elongation at break point (E), tear strength (TT), water vapour permeability (WVP) and oxygen permeability (OP) of films were evaluated. The interactions between biopolymers showed quadratic effects ( P < 0.01) on TS, E, PT, TT and WVP values. Scanning electron microscopy (SEM) was performed to investigate the microstructures of composite films. The proportion of ingredients required to produce the optimum composite films was determined to be: WPI (g):G (g):SA (g) = 8.0:12.0:5.0. Overall, films (WPIGSA-9) produced using the combination of WPI (g):G (g):SA (g) = 10.0:16.0:14.0 demonstrated the best barrier to oxygen (8.00 cm 3 μm/m 2 d kPa); while films (WPIGSA-1) showed the best barrier to water vapour (48.04 g mm/kPa d m 2); films (WPIGSA-6) using the combination of WPI (g):G (g):SA (g) = 10.0:17.5:22.5 had the best mechanical properties of all of the experimental composite films tested.