Wool keratin film for active food packaging

Innovative packaging materials that can extend the shelf-life, contributing to consumer safety, being environmental friendly, are subject of great interest by food and packaging industry. Particularly, biopolymers such as lipids, proteins, polysaccharides and mixtures thereof have been investigated to enhance the properties of films as packaging materials. In food technology, active packaging with antibacterial property is a concept based on incorporating an antimicrobial compound inside the packaging material or using one with inherent antimicrobial properties. Keratin is a natural biodegradable protein extracted from wool and other natural resources for its properties has been used to produce nanofibers because of its special absorption characteristics and as scaffolds for human body. Keratin films don't have good mechanical properties so it was blended with citric acid as compatibilizer and plasticizer, which is used in polymers as polyvinyl alcohol, starch and polycaprolactone; moreover citric acid has antibacterial properties and is used in many food products as natural preservative. The aim of this work is to obtain a film for active food packaging, produced using keratin and citric acid in aqueous solution. The film was characterized by means of TGA, DSC and FT-IR. Moreover, mechanical properties, antibacterial efficiency, transparency and stability in water were evaluated. Finally, a carrot shelf-life preserved with the keratin-citric acid film was qualitatively assessed and compared with a commercial PET film for food packaging.