A review article titled 'Recent applications of biopolymers derived from fish industrial waste in food packaging' was published in Polymers by Francesca Rionetto from the Department of Innovative Engineering, University of Salento, summarizing the Recent advances in the valorization of fish industry waste and the potential to reuse these by-products in a circular economy approach for the preparation of bioplastics for food packaging.
Fish Maw
Gelatin is a denatured protein derived from the partial hydrolysis and heat treatment of collagen. It consists of a set of proteins and polypeptides of different molecular weights, the composition of which mainly depends on the parent collagen and the extraction procedure. During hydrolysis, the natural molecular bonds between individual collagen chains are broken down, leaving a mixture of single- or multi-chain polypeptides, each with an extended left-handed helical conformation and containing 50-1000 amino acids. Two types of gelatin, type A and type B, are obtained by acid hydrolysis and alkaline hydrolysis, respectively.
The extraction and application of gelatin from fish manure has attracted widespread interest due to religious issues and health concerns about the spread of disease to humans. Gelatin is an important industrial biopolymer with remarkable gelling and film-forming properties that can be used in food, pharmaceutical and other related fields.
Due to good film-forming properties, low cost, biocompatibility and biodegradability, fish gelatin has recently been recommended for the preparation of biodegradable films in active food packaging to replace traditional non-biodegradable polymers and Other mammalian based gelatins. Gelatin is easily processed by applying thermal and mechanical stress in extrusion-based techniques. To increase flexibility, plasticizers are used as internal lubricants, which improve molecular mobility. A gelatin film can be obtained by casting an aqueous gelatin solution. They are odorless, colorless, transparent, water-soluble, and more flexible than other bio-based films for food packaging. Because the melting point of gelatin is close to body temperature, gelatin-based films can be used to prepare edible films. Furthermore, fish gelatin has shown great potential as an excellent matrix for bioactive compounds with enhanced functions, such as antioxidants/antibacterials
Water resistance is improved by laminating the fish gelatin film with a moisture-resistant biodegradable polymer in a multilayer film with moisture and oxygen barriers optimized for specific packaging and conditions. Matucci et al. Taking sodium montmorillonite plasticized gelatin as the inner layer, cross-linked dialdehyde starch and plasticized gelatin film as the outer layer, and hot pressing to obtain three-layer gelatin film. The multilayer films exhibit compact and uniform microstructures due to the highly compatible individual layers that can interact through strong hydrogen bonds. The same authors also prepared a multilayer structure with a PLA film as the outer layer, which has a higher water vapor permeability than other commercial polymers such as high-density polyethylene or polyvinyl chloride.
