Fabrication, characterization, and antibacterial activities of edible zein films enhanced with three food additives for effective preservation of emerald green grapes

A new edible zein film modified with food additives sucrose esters (SE), glyceryl monostearate (GMS), and potassium sorbate (PS) was developed and successfully applied to the preservation of emerald green grapes. The physicochemical properties, antioxidant and antibacterial activities of the edible PS/GMS/SE/Zein films were investigated. The film had a relatively thin thickness of 0.27±0.0001 mm, higher tensile strength 15.34±0.57 MPa, and lower water vapor permeability 3.05±0.01 g·mm/m 2 ·h·KPa. Scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) confirmed that the introduction of SE and GMS improved the smoothness, density, and barrier function of zein films, and the formation of intermolecular hydrogen bonds and the hydrophobic structure of zein were the main reasons for the enhancement of their membrane performance. Furthermore, PS/GMS/SE/Zein films had good antioxidant properties and exhibited obvious antibacterial performance against Staphylococcus aureus, Escherichia coli, and Bacillus cereus. As an edible coating on emerald green grapes, the zein film incorporated with food emulsifier SE, GMS, and preservative PS formulation effectively reduced weight loss, prevented color changes, preserved total phenol and ascorbic acid levels, enhanced antibacterial ability, and extended shelf life. This study provides a new strategy for enhancing the biological activity, mechanical properties and hydrophobicity of zein-based edible films, which can be used as potential alternatives for petrochemical plastics and provide more opportunities for fruit and vegetable food packaging. • A new edible zein film modified with three food additives was developed. • Sucrose esters, glyceryl monostearate, and potassium sorbate improved performance of pure zein film. • The films exhibited excellent structural characterization and physical properties. • They showed good antioxidant properties and antibacterial performance. • The films exhibited better packaging performance to emerald green grapes.