Optimization of gelatin-microcrystalline cellulose-based composite biodegradable films using response surface methodology

In recent years, there has been growing interest in biodegradable materials derived from renewable resources due to their environmental benefits. This study aimed to optimize the formulation and processing conditions for composite biodegradable films based on gelatin and microcrystalline cellulose (MCC), with glycerol as a plasticizer, using Response Surface Methodology (RSM). A Box-Behnken design was employed to evaluate the effects of gelatin (2.5-3.5% w/v), MCC (0.5-1.5% w/v), and glycerol (0.8-1.2% w/v) on film thickness, moisture content, colour parameters (L*, a*, b*), tensile strength, elongation at break, penetrability, and extensibility. The results showed that gelatin and MCC significantly enhanced film thickness, tensile strength, Water vapour transmission rate and puncture resistance. Moisture content was governed by the hydrophilic nature of the formulation components, and colour attributes were moderately affected by polymer composition. Multi-response optimization identified 3% gelatin, 1% MCC, and 1% glycerol as the optimal formulation. Under these conditions, the films exhibited a thickness of 0.171 mm, moisture content of 9.33%, lightness (L*) of 76.03 and improved instrumental texture properties. Overall, the optimized gelatin-MCC composite biodegradable films demonstrated a balanced combination of strength, flexibility, and acceptable visual properties, highlighting their potential application as sustainable food packaging materials.