## 3 Results and Discussion
### Chemical Composition of HS-SPME  
The HS-SPME method of analysis of volatile organic compounds (VOCs) obtained from the herbs of two _Origanum vulgare_ L. varieties treated with organic and mineral fertilizers showed the presence of typical compounds present in essential oils isolated from different varieties of this herb species. The main components of the volatile fraction of the dried product for both varieties of oregano were identified as carvacrol and thymol (Figures 2 and 3) [3,10]. However, the content of these ingredients varied according to the variety as well as the fertilization method used. The highest carvacrol content was found in the volatile fraction of dried Aureum, while thymol was found in the dried mass of Hot & Spicy. The variable ratio between carvalacrol and thymol depending on the variety of oregano was also found by [PERSON] et al. [25]. When analyzing the test results of the composition of the dried  
Figure 1: Water content decrease in _Origanum vulgare_ L. leaves during vacuum-microwave drying after convection pre-drying (CPD) at 40 \({}^{\circ}\)C followed by VMFD. In the figure: MR= moisture ratio, A = variety Aureum, HS = variety Hot & Spicy, (O) = organic fertilization, (M) = mineral fertilization, t = temperature. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Variety**} & \multirow{2}{*}{**Fertilization Method**} & \multirow{2}{*}{**Stage of Drying**} & \multicolumn{4}{c}{**Constants**} & \multicolumn{2}{c}{**Statistics**} & \multicolumn{2}{c}{**Drying Time**} & \multirow{2}{*}{\(\mathbf{M_{\text{ev}}_{\text{ub}}}\)} \\ \cline{5-10}  & & & \(A\) & \(k\) & \(n\) & \(\mathbf{\kappa}\) & \(\mathbf{\kappa}\) & \(\mathbf{\kappa}^{2}\) & (min) & (\%) \\ \hline \multirow{4}{*}{Aureum} & organic & CPD & 1 & 0.006607 & 0.8519 & 0.00817 & 0.9974 & \multirow{2}{*}{276} & \multirow{2}{*}{3} \\  & & VMFD & 0.4751 & 0.04798 & 1.3037 & 0.01073 & 0.9973 & & \\ \cline{1-1} \cline{3-10}  & & CPD & 1 & 0.007941 & 0.8715 & 0.005357 & 0.9993 & & \\ \cline{1-1} \cline{3-10}  & & VMFD & 0.3800 & 0.09666 & 1.5523 & 0.006244 & 0.9990 & & \\ \hline \multirow{4}{*}{Hot \& Spicy} & organic & CPD & 1 & 0.008182 & 0.8095 & 0.006950 & 0.9983 & & \\ \cline{1-1} \cline{3-10}  & & VMFD & 0.4859 & 0.04384 & 1.5468 & 0.006976 & 0.9991 & & \\ \cline{1-1} \cline{3-10}  & & CPD & 1 & 0.01370 & 0.7482 & 0.011269 & 0.9964 & & \\ \cline{1-1} \cline{3-10}  & & VMFD & 0.4163 & 0.03255 & 1.7861 & 0.013759 & 0.9962 & & \\ \hline \hline \end{tabular}  
* In the table: A = coefficient corresponding to the initial value of MR, k = drying constant, n = exponent, R2 = coefficient of determination, RMSE\({}^{2}\) = lowest values of the root-mean-square error, McNb = final water content.  
\end{table} 
Table 3: The Page’s model parameters, drying time and final water content in leaves of _Origanum vulgare_ L. in vacuum-microwave drying (CPD 40 \({}^{\circ}\)C-VMFD 240 W). oregano volatile fraction, a clear trend was also observed in which the carvacrol content increased in the headspace for the organically treated oregano. The increased carvacrol content in the raw material of oregano was also confirmed by [PERSON] et al. [2]. The increase in the percentage of this ingredient recorded in the studies for this herb when fertilized organically as opposed to minerals ranged between 8.4% for the Aureum variety and 19.3% for the Hot & Spicy variety (Table 4). A similar relationship between the fertilizer used and the content of the main compounds of the headspace fraction was noted by [PERSON] et al. [16] in the herb of the common basil _Ocimum basilicum_ L. In their study, the authors concluded that organic fertilization had an impact on the growth of the main components of the volatile fraction of the dried mass of two varieties of common basil. The organic fertilization involved a peat substrate that was fortified with common nettle extract (10% in terms of weight) and horse manure (20% in terms of weight), followed by soil-applied fertilization with Biolisa N 12,5. [PERSON] et al.