Effect of green coffee oil as a natural active emulsifying agent on the properties of corn starch-based films

Green coffee oil can be used as a biologically active emulsifier. In this study, corn starch-based composite films with different concentrations of Arabica coffee oil (ACO) and Robusta coffee oil (RCO) were prepared using the solution-casting method. The film-forming properties and physicochemical characteristics of the composite films were investigated, and their antibacterial activity was evaluated. With the addition of coffee oil, the mechanical properties of the corn starch-based films improved, and the thickness, UV light-shielding performance and transparency of the cornstarch-based film significantly increased. Compared with the oil-free or RCO addition films, the addition of ACO significantly reduced the solubility and water vapor transmission rate of the films, resulting in an improvement of waterproof performance of the films. Furthermore, adding of coffee oil formed micelles in the composite film, in which the active ingredient exhibited S. aureus inhibitory activity. The results showed that ACO, as bioactive vegetable oil, can be used as a natural surfactant to improve the overall performance of starch-based films. At the same time, ACO can meet the needs of consumers to reduce the use of chemical additives, and its application in corn starch-based composite films could become a promising food packaging platform.