Preparation and characterization of the protein edible film extracted from the migratory locust (Locusta migratoria)

In recent years, there has been more research on the use of edible insects in food additives and nutrition due to their high protein content. However, such an abundant natural protein source has not been explored for its potential use as edible film for green packaging. In this study, the locust (Locusta migratoria) was first used as a new source of protein to develop edible film by solvent casting. The parameters of protein (6–8 %), glycerol (35–45 %) content and pH (9−11) were set to evaluate the physicochemical properties of films. The FTIR and XRD results showed that there was good compatibility between protein and glycerol due to the hydrogen bonding interactions. The positive correlation between protein concentration and glass transition temperature was confirmed by DSC. All the samples had hydrophilic surface and the protein and glycerol content could both increase the WVP of films. Response surface methodology (RSM) was used to determine the best mechanical properties of the film. The results showed that barrier and mechanical properties of edible films from the locust were comparable with unmodified cereal protein, indicating the potential application value in food packaging. It also means that edible insect proteins, an untapped resource of proteins, can be harnessed to develop green biomaterials.