Modification strategies of proteins for food packaging applications

Abstract

Biopolymers found in nature are complex molecules that adopt precise and definite shapes and structures. They comprise a diverse and versatile type of materials that normally exhibit useful properties such as biocompatibility, biodegradability, non-toxicity, adsorption capacity, film-forming ability and hidrophilicity. In addition, they can be tailored to confer important properties to meet specific needs and be modified to be useful in various applications such as food packaging. In general, biopolymers such as polysaccharides and proteins are widely used for this last application in which the main objective is to maintain the quality and safety of the food products contained in the packaging, for a specific time period. However, certain biopolymers do not show optimum properties to suit the use in food packaging due to their hydrophilic nature, poor mechanical properties and low thermal resistance. For these reasons, both modification and preparation strategies of these natural materials are commonly developed in order to obtain films with optimized properties for food packaging. This chapter focuses on a review of the synthetic strategies that can be used to improve specific properties of materials made from proteins, specifically from soy proteins. These improvements seek to satisfy the needs of the applications in which these materials will be used. General strategies as the formation of chemical cross-linked networks using biodegradable and non- cytotoxic agents; graft with synthetic monomers; physical mixture with nano reinforcements and formation of a bilayer film using other components are described among others. The extent and variety of the improvements made in the final properties of the films described using various modifications and preparation methodology open a promising field for the application of these environmentally friendly materials, not only as coating or packaging materials, but also in varied and diverse applications in small and large scale.