# Nanoparticles Based-Plant Protein Containing
## 3 Results  
Dynamic light scattering analysis (DLS) is a technique to determine the particle size distribution of NPs. Figure 1 indicates the average hydrodynamic size of NPZRO, which is about 154.5 nm. This value corresponds to the values reported in the literature [22; 28; 42; 43; 44]. Moreover, scanning electron microscopy (SEM) was used to study the surface topography, and particle size of NPZRO. The SEM pictures of NPZRO are shown in Figure 2. According to these images, the shape of NPZRO particles is spherical and uniform. The results show the formation of capsules with both nano and micro dimensions. In addition, the images show the narrow distribution of nanoparticles, which is in the range of 70 to 200 nm. The results of this study are completely consistent with the results of other researchers [22; 28; 42; 43; 44]. The stability of the prepared nanoparticles was investigated by TGA and DSC analyses, which are based on the changes in sample weight by heating at a constant rate. The obtained results of TGA and DSC analysis are shown in Figure 3. As can be seen, thermograms curves of pure zein nanoparticles and NPZRO are very similar and indicate two-weight losses at the temperature range of 30 to 600 \({}^{\circ}\)C. The physically adsorbed water and somewhat bound water are removed at 40 to 300 \({}^{\circ}\)C, approximately 20% of the sample weight. The severe weight loss of the second stage at 300 to 550 \({}^{\circ}\)C, which is about 50% of the total weight of the sample, is related to the destruction of the protein structure of the zein and rosmary. In addition, it is noteworthy that NPZRO shows slightly higher thermal stability than pure zein. It is noteworthy that nanoparticles show slightly higher thermal stability than pure zein. Therefore, the thermal degradation of the second stage starts at about 150 \({}^{\circ}\)C.  
The interaction between zein nanoparticles and rosmary as well as functional groups was investigated by FT-IR spectroscopy. The observed broad frequencies of all three spectra in the range of 3100-3500 cm\({}^{-1}\) are attributed to the stretching vibrations of the O-H of alcohols, carboxylic acids, and water (Figure 4). The symmetric, and asymmetric stretching absorption bands of -CH\({}_{3}\) groups of net rosmary can be seen in 2850 and 2925 cm\({}^{-1}\), respectively. As can be seen, after interaction between zein nanoparticles and rosmary, these peaks are removed. Due to the presence of C=O groups in all three net rosmary, net zein and NPZRO, the sharp stretching vibrations are observed in 1621-1660 cm\({}^{-1}\). However, this frequency in NPZRO has shifted to lower energies. The frequencies observed  
Figure 1: Average hydrodynamic size of NPZRO. Figure 2: SEM images for NPZLA (**A**,**B**). in 1457 and 1376 cm\({}^{-1}\) in rosemary spectrum are attributed to N-H bending vibration and the stretching vibration of C-O (amide), respectively. Moreover, the FT-IR spectra of net zein and NPZRO have similar patterns, indicating no notable changes in the critical bands or functional group's status. The FT-IR spectra can also be used to study particle configuration; with increasing particle size, the peak width decreases, but the intensity increases. As can be seen, the peak intensities of the NPZRO have increased compared with their corresponding absorption bands in net zein. Figure 4: FT-IR spectrum of pure zein, pure RO, and NPZRO. Figure 3: The curves of TGA (**A**) and (**B**) DSC of pure zein and NPZRO at a heating rate of \(10\ ^{\circ}\)C min\({}^{-1}\) under an N2 atmosphere. Ultraviolet-visible spectroscopy (UV-Vis) was applied to determine the amount RE-loaded in zein nanoparticles. To evaluate the amount of essential oil release over time, as a sample, capsules prepared with plant polymer were subjected to release. The release of loaded samples was examined by the dialysis method, in which the samples were placed in dialysis bags and immersed in a PBS solution with a pH of 7 and ambient temperature.