The physical, biomechanical and chemical properties of the composite biodegradable films are examined by their chemical composition, structure, processing conditions and economics. Therefore, the purpose of the study was to develop standard composite biodegradable films by optimizing the process (drying time and temperature) and composition (whey protein concentrate; WPC and sodium alginate; SA).
Composite WPC–SA films were developed using the Box–Behnken design of response surface methodology (RSM), with individual and interactive effects of process variables on the response variables (quality characteristics). Three independent factors at three different levels (WPC: 5–7 g, SA: 0.1–0.5 g and drying temperature: 35°C–45°C) were evaluated for their effects on physical and biomechanical properties, namely, thickness, penetrability, moisture content, water vapor transmission rate (WVTR), density, solubility, transmittance and color variables. The results were analyzed using ANOVA. For each response, second-order polynomial regression models and resulting equations were developed.
The response surface plots were constructed for representing a relationship between process parameters and responses. All responses were optimized as the best and desired, namely, thickness (180 µm), penetrability (7.63 N), moisture (28.05%), WVTR (1.87 mg/m2t), solubility (36.12%), density (1.33 g/ml), transmittance (40.55%), L* value (52.50), a* value (0.35) and b* value (13.70). The regression models exhibited “good fit” of experimental data with a high coefficient of determination. A close agreement was found between experimental and predicted values.
These biodegradable films can be promisingly used in the food packaging system without the problem of disposability.
The composite films with proteins and polysaccharides can be developed, which have improved physical and biomechanical properties.
