Encapsulation of Rosemary Essential Oil into Biodegradable Polymers for Application in Crop Management

In recent years, there is an increasing demand for replacing hazardous agrochemicals in intensive farming systems with natural pesticides, such as essential oils. Essential oils are sources of antimicrobial compounds and have the potential to combat weeds, pathogens and insects. Their use in greenhouse cultures seems promising, but their action is very rapid due to their high volatility. The aim of the current study was the encapsulation of essential oils into biopolymers for enhancing their efficiency and controlling their release. The essential oil of Rosemarinus officinalis (rosemary) (REO) was encapsulated in zein and polylactic acid (PLA) using electrohydrodynamic processing (EHD) and extrusion. The effect of various process parameters was evaluated through scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Attenuated Total Reflectance FT-IR Spectroscopy (ATR-FTIR). Ultraviolet–visible spectroscopy (UV–VIS) determined the encapsulation efficiency. The stability and release of encapsulated compounds was also tested during their storage in controlled conditions. The examined encapsulation parameters affected in different ways the morphology and properties of the structures. Encapsulation efficiency was in the range of 70–90% with EHD presenting the highest values. ATR-FTIR analysis confirmed the presence of REO in the structures. The produced structures offer great potential to be incorporated in greenhouse films to replace agrochemicals.