The influence of different plasticizers on the mechanical properties of active edible bilayer films

Abstract

In addition to potentially resolving environmental issues that come from plastic and food waste, active biodegradable packaging is being developed to increase the shelf life, quality, and safety of packaged food. In order to overcome the drawbacks of monolayer hydrocolloidbased coating, such as poor mechanical and barrier properties, the design of bilayer hydrocolloidbased coating has been structured using pullulan and gelatin. Sugar alcohols are widely used for the plasticizing of biopolymer-based films. The aim of this work is to investigate the influence of different sugar alcohols – xylitol, mannitol, and glycerol on the mechanical properties of pullulan/gelatin bilayer films. Among investigated plasticizers, glycerol has demonstrated the best plasticizing effect, giving a bilayer film with the value of elongation at break which is 66.5 and 88.4% greater than the same values for the bilayer films prepared using xylitol and mannitol. The formulation with glycerol has been applied for the preparation of active edible coating using the mixture of two hydrolats – lemongrass and curry plant. Obtained coatings have shown great potential for the improvement of packaged cheese shelf-life.