The physiochemical and preservation properties of fish sarcoplasmic protein/chitosan composite films containing ginger essential oil emulsions

Abstract Active films with essential oils have attracted more attention in recent years. In order to improve the solubility and stability of ginger essential oil (GEO) in film forming solutions, GEO coarse emulsion and nanoemulsions were prepared named CGEO (z‐average = 799.53 nm), NGEO‐1 (z‐average = 114.71 nm) and NGEO‐2 (z‐average = 59.30 nm), respectively. And the effect of concentration (0.5% and 1.0% v/v) and particle sizes of GEO emulsions on the physiochemical and preservation properties of fish sarcoplasmic protein and chitosan blend based edible films were studied in this study. The elongation at break significantly ( p < .05) increased after adding GEO emulsions, and the light transmittance, water vapor permeability and water solubility were the lowest when NGEO‐2 was incorporated into films. The antioxidant and antimicrobial activities of films were concentration‐dependent. Furthermore, all the films were applied into packaging red sea breams fillets, and the results of total viable counts, pH and thiobarbituric acid demonstrated that SP‐CH films with GEO emulsions, especially nanoemulsions obviously prolonged the shelf‐life of fillets during 4°C. Practical Applications In recent years, the research about incorporating essential oils into edible films to prepare active edible films due to their antimicrobial and antioxidant properties have been more documented. In this study, fish sarcoplasmic protein and chitosan were chosen as film‐forming materials to prepare active films with ginger essential oil emulsions. The physicochemical, mechanical, optical properties of films showed that the films have the basic characteristics as food packaging materials. The releasing and antioxidant property of films indicated that the active films have a potential application in packaging food which was easy oxidized. The basic properties of films combined with oxidation indicators (total viable count, pH and thiobarbituric acid reactive substances) would provide the scientific basis for developing active films and their application for food packaging, such as seafood, meat, fruits and vegetables.