Production of edible coatings with twin-nozzle electrospraying equipment and the effects on shelf-life stability of fresh-cut apple slices

In this study, apple slices were coated with electrospraying and dipping method for comparison of the coating efficiency, material uptake, color changes, and microstructure of coated surfaces. In electrospraying of 70% oil emulsion, a lower voltage was required for stable cone-jet geometry compared to the 80% oil emulsion which had the highest electrical conductivity and lowest viscosity. The material uptake of dip-coated samples was similar; however, the material uptake of electrospray coated samples was found between 0.051 and 0.122 mg emulsion/g apple. Electrospray coated apple slices had lower weight loss compared to the control and dip-coated samples, although the applied coating material was significantly lower. The total color change of electrospray coated samples was similar to the control; however the change in dip-coated samples was significant. The coating was uniform on the surface of electrospray coated sample, but a couple of pinholes and irregularities were visible in the microstructural image of dip-coated sample.