## 3 Results and Discussion
### Pressing Efficiency, Capacity, and Cold-Pressed Oil Yield  
The preparation of the material for pressing, granulation composition, and hydrothermal treatment conditions, in addition to the press design and pressing conditions, significantly affect the oil yield during pressing [53; 54; 55]. The moisture and oil content in the seeds, which result from the seed's characteristics and preparation, dictate the pressing conditions and further influence the yield of cold-pressed oil. The moisture content in the initial material ranged from 4.98 \(\pm\) 0.09% in Sample 10 to 6.49 \(\pm\) 0.15% in Sample 11 (Table 3). \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Parameters** & **Results** \\ \hline \multirow{8}{*}{
\begin{tabular}{c} **Polar** \\  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Sunflower Seed (Raw Material)**} & \multicolumn{4}{c}{**Cold-Pressed Case**} & \multicolumn{4}{c}{**Ind indicators of Cald-Pressed Oil Yield**} & \multicolumn{4}{c}{**Cold-Pressed Oil Yield**} \\ \hline \begin{tabular}{c} **Density** \\ **(C)** \\ **(C)** \\ \end{tabular}  \\
2 & 5 & 2.5 & 5.34 \(\pm\) 0.10 & 50.96 \(\pm\) 0.02 & 6.01 \  
The oil content in the initial seed samples varied from 41.38 \(\pm\) 0.58% tel quel to 50.96 \(\pm\) 0.07% tel quel in samples containing hull and impurities to 55.08 \(\pm\) 0.90 g in clean kernels. Since the highest moisture content and the lowest oil content were observed in the sample with the highest hull (20%) and impurity (10%) content, while the lowest moisture content and highest oil content were found in the sample without hulls and impurities, these results confirm the significant influence of hull and impurity content on both the pressing process and oil yield [8; 56; 57]. The pressing efficiency (yield of pressed oil) ranged from 39.24 \(\pm\) 2.27% (\(w\)/\(w\)) in the sample without hulls and impurities (sample 10) to 65.12 \(\pm\) 0.06-76.52 \(\pm\) 0.67% (\(w\)/\(w\)) in samples with the following compositions: 5% hulls and 2.5% impurities (sample 2), 10% hulls without impurities (0%) (sample 9), 15% hulls and 2.5% impurities (sample 7), and 20% hulls and 5% impurities (sample 5). Pressing of the raw material with hull contents of 5%, 10%, 15%, and 20%, and impurity contents of 0%, 2.5%, and 5%, resulted in yields exceeding the average of 64.75 \(\pm\) 15.00% (\(w\)/\(w\)). The highest oil yield, 76.52 \(\pm\) 0.67% (\(w\)/\(w\)), was achieved by pressing material with 20% hull and 5% impurity content, as well as material with 15% hull and 2.5% impurity content, yielding 74.66 \(\pm\) 0.36% (\(w\)/\(w\)). These results indicate that, in this case, the presence of hulls in the material contributes to improved oil yield, although the oil yield also depends on the oil content in the raw material. [PERSON] et al. [8] investigated the yield of cold-pressed oil from the seeds of 20 newly developed sunflower hybrids and reported yields ranging from 20.10 \(\pm\) 2.82% in seeds with 46.74 \(\pm\) 0.99% hull content to 75.61 \(\pm\) 1.99% in seeds with 30.10 \(\pm\) 0.27% hull content. In their study, the oil yield was lower in samples with high hull content because they involved a confectionary hybrid with significantly lower oil content (23.84 \(\pm\) 0.38%) compared to an oilseed hybrid where yields exceeded 75% (41.66 \(\pm\) 3.16% oil). Pressing oil yield and optimization are also studied in other plant species. [PERSON] et al. [58] determined an oil yield of 73.38 \(\pm\) 0.31% (\(w\)/\(w\)) for tobacco seeds at a pressing temperature of 70 \({}^{\circ}\)C and a screw speed of 32 rpm. On the other hand, [PERSON] et al. [59] investigated the oil yield of sesame, pumpkin, flax, milk thistle, and hemp during cold-pressing and obtained values ranging from 13.37 \(\pm\) 0.35% to 30.60 \(\pm\) 1.69%, which is significantly lower compared to the lowest value obtained in the tested sample without hulls and impurities (sample 10).