# Nanoparticles Based-Plant Protein Containing
## 4 Discussion  
Oil compounds (essential oils) are sensitive and have useful antimicrobial and antioxidant properties, and in order to increase the stability of these compounds and control their release, the encapsulation process can be used. There are different methods for encapsulating plant essential oils, which differ from each other in terms of process conditions and encapsulation efficiency. In this research, zein, which is a natural polymer with wide properties and applications in the food and pharmaceutical industries, was used.  
In summary, the average size of NPZRO was 154.5 nm that measured by DLS analysis. The NPs size were between 70-200 nm based on the SEM results, which was consistent with the results of former studies [21; 37; 45]. Also, the results of FT-IR appearance of the main distinctive peaks of zein and RE in the spectrum of all the NPZRO indicate a higher ability of zein NPs to encapsulate RE molecules. The RE's drug EE within the nanoparticles was ca. 71%. Many studies reported that the polymeric barrier is able to control the RO release in vitro release suggests [21; 46]. Figure 4 shows that the developed NPs enable a more controlled and sustained in vitro release of the loaded EO.  
Recently, the high potential of plants EO is well known as a source of various of chemical compounds with important biological activities. However, many of these plant EO have shown poor solubility in aqueous systems, short shelf life, high chemical instability and chemical complexity that affect the biological activity of their various compounds.  
These challenges limit their effective application. Controlled release systems such as polymer NPs provide a solution to these problems. Choosing the right encapsulation  
Figure 5: The RE-free and NPZRO’s release profiles.  
method is the key to obtaining a formula (NPs) with suitable properties. Choosing the right encapsulation method is key to obtaining a formula (NPs) with suitable properties different applications. Based on the results of our study and previous studies, the use of biopolymer nanoparticles as carrier of plant extract is most suitable and safe methods [45; 47].  
The NPs-based biopolymer as carriers of active agents are protection in the application environment, enhancing of cell of tissues internalization, protection against enzymatic degradation, bioavailability improvement, design of sustained-release systems of bioactive compounds, enhancement of solubility, affected area targeting, reduction of toxicity, and masking of unpleasant odor and taste [45; 48]. Literature illustrated that mostly dermal and oral routes are employed for the delivery of formulation based of encapsulated plant extracts.  
The result suggests that the bioactivity of RE would be influenced by the chemical composition change [45]. The use of biopolymer plant-based can be safe and have minimal change in RE bioactivity. Although studies associated with the useful effects of the lavender oil encapsulated in nanoparticles are still in progress [45], However, due to being inexpensive, safe, and affordable, zein biopolymer can be a promising agent with potential application in essential oil encapsulating systems.