## 3 Results and Discussion  
### Impact of Ingredients and Processing Conditions on Extrusion-Cooking Process  
The analysis showed that the efficiency of the extrusion-cooking process was significantly influenced by three main technological factors: screw speed, moisture content of the mixture and the level of fresh blueberry addition (Table 4). The interactions between these factors affected both the processing capacity of the system and the material flow efficiency through the extruder-cooker barrel. One of the most noticeable trends was the increase in efficiency with higher screw speed. For each tested combination of moisture level and blueberry content, extrusion-cooking at 100 rpm resulted in clearly higher efficiency compared to 60 rpm. This effect can be attributed to more efficient material transport through the barrel and more dynamic die filling. The increase in screw speed plays a crucial role in enhancing the overall efficiency of the extruder, as it promotes better flow and reduces the resistance of the material, thereby improving it. For example, in the case of a mixture without blueberries and 36% moisture, increasing the screw speed from 60 to 100 rpm raised the throughput from 21.84 to 36.16 kg/h, representing an increase of \begin{table}
\begin{tabular}{c c c c} \hline
**No.** & **Compound** & **Calibration Curve** & **R2** \\ \hline
1 & protocatechic acid & y = \(-\)0.0254426x\({}^{2}\) + 1.46612x + 0.0137605 & 0.997 \\
2 & p–OH–benzoic acid & y = \(-\)0.0116753x\({}^{2}\) + 1.43904x + 0.164956 & 0.997 \\
3 & vanillic acid & y = 0.000116384x\({}^{2}\) + 0.194029x \(-\) 0.00311 & 0.998 \\
4 & caffe acid & y = \(-\)0.0182712x\({}^{2}\) + 2.42109x + 0.436786 & 0.995 \\
5 & syryngic acid & y = \(-\)0.000546324x\({}^{2}\) + 0.259824x \(-\) 0.00264286 & 0.986 \\
6 & p–coumaric acid & y = \(-\)0.0165714x\({}^{2}\) + 2.05818x + 2.05818 & 0.993 \\
7 & ferulic acid & y = \(-\)0.000407832x\({}^{2}\) + 0.380126x + 3.30005 & 0.994 \\
8 & synapic acid & y = \(-\)0.00315979x\({}^{2}\) + 0.55236x \(-\) 0.0620381 & 0.998 \\
9 & salicylic acid & y = \(-\)0.0338427x\({}^{2}\) + 3.26378x + 0.82676 & 0.998 \\ \hline \end{tabular}
\end{table} 
Table 3: Parameters of the calibration curve for nine different phenolic acids. over 60%. Another important factor was the addition of fresh blueberries, which tended to reduce process efficiency, especially at higher addition levels. This was likely due to the presence of bioactive components--such as fiber, pectin, and additional moisture from the fruit--which increased the viscosity and flow resistance of the mixture. As a result, at 30% blueberry content, with 36% moisture and 60 rpm, the throughput dropped to 14.40 kg/h, the lowest value recorded among all tested combinations. In comparison, under the same conditions without blueberries, the throughput was 21.68 kg/h, confirming the negative impact of a raw material high in moisture and fiber. The effect of moisture content on extrusion-cooking efficiency was less consistent and depended on other factors. At lower blueberry levels (0-10%), a higher moisture content (36%) improved throughput, likely due to reduced internal friction and better dough formation. However, at 30% blueberry addition, this effect disappeared or reversed--excess moisture combined with high fruit content led to overloading of the feed system and material flow difficulties, significantly reducing the mass efficiency. The results obtained in the present study showed that increasing the screw speed from 60 to 100 rpm led to a significant improvement in productivity (e.g., from 21.6 to 36.0 kg/h for a blend without blueberries). This confirms the general relationship between increased material transport and increased extruder productivity. Similar trends regarding the influence of processing parameters on extrusion-cooking efficiency were reported by [PERSON] et al. [34], who analyzed the production of gluten-free extrudates based on rice and legumes.