Starch-based films and food coatings: An overview

Abstract

Native and modified starches have received considerable attention for biodegradable films formulation due to their completely biodegradable nature, edible characteristics, and low cost. Development and characterization of starch films obtained by: (i) casting, (ii) blown extrusion and (iii) the thermo-compression moulding process are described. The rheological properties of filmogenic suspensions, the barrier properties, and the mechanical resistance of the obtained films are reported. Addition of specific additives to the formulations modifies the film functionality transforming them into active materials. Diffusion of antimicrobial agents such as potassium sorbate from the active starch film, as well as their efficacy in dairy products is discussed. Likewise, reinforcing agents lead to composite materials with improved mechanical resistance. Starch-based materials show higher permeability to carbon dioxide than to oxygen, which is useful to control the respiration rate of fruits and vegetables. The application of active starch-based coatings to strawberries and Brussels sprouts in order to prolong their refrigerated storage life is analyzed. A detailed overview on the formulation and performance of starch-based films employing industrial and lab-scale methods, as well as the application of starch coatings to improve food quality is presented, with the aim of analyzing the possibility of development and application of such materials.