Development and optimization of whey protein- Lepidium perfoliatum gum packaging films: An approach towards antimicrobial and biodegradable films

Abstract

The use of plastic materials as the main packaging components in the food industry has caused widespread environmental and economic problems, so the use of edible films and coatings with diverse capabilities can be considered as a good choice. This study aimed to optimize a composite edible film based on whey protein concentrate (WPC) and Lepidium perfoliatum L. gum (LPG) using transglutaminase enzyme through Response Surface Methodology and loaded with oregano (Origanum vulgare L.) essential oil. The optimum value of independent factors with regard to minimum thickness, moisture, and solubility of films was LPG concentration 0.5 % w/v, WPC/LPG ratio 2.9, enzyme content 10 % and glycerol concentration 15 % v/v. The optimum responses for thickness, moisture, and solubility of films were 130 µm, 8.13 %, and 53.61 %, respectively. The physicochemical properties, X-ray diffraction analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, mechanical and thermal properties of optimized films were also studied. Microscopic images showed that the prepared films had a rough and irregular surface, while the cross-section micrograph indicated a smooth and crack-free surface. The physicochemical properties revealed a denser packing of polymer chains and semi-crystalline structure of films. The water vapor permeability of the film was 1.21 × 10−10 ± 0.03 g/m s Pa. The obtained results confirmed that preparation of composite films based on WPC and LPG was successful and the loaded film with oregano essential oil can be used for biodegradable food packaging.