## 3 Results and Discussion
### Total Polyphenol Content  
The content of polyphenols in food varies and is influenced by numerous internal and external parameters, including the temperature used, light exposure, oxygen, enzymes, proteins, metal ions or bonding with other food components [27; 28].  
The total polyphenol content (TPC) in the studied variants of confitures significantly depended on the method of production (Table 2). Immediately after production, the jams obtained under lowered pressure contained 16% higher TPC than those obtained under atmospheric pressure in the thermomix. Also in a study on bilberry jams with herbs, the use of vacuum during production was shown to preserve 19-23% more polyphenols compared to cooking in an open pan [15].  
The 180-day cold storage of both types of honeysuckle berry confitures resulted in a significant reduction in TPC. However, the rate of polyphenol degradation varied. A higher rate of degradation changes was noted in confiture from the evaporator where 77% of the initial amount of polyphenols remained. After the same storage time, 75% of the initial amount of polyphenic compounds remained in the confiture from the thermomix. Nevertheless, at the end of storage, both types of confitures showed similar TPC values. The reduction in polyphenol levels during storage depends on the type of product, time and storage conditions. In another study, after 20 weeks of storage of black carrot jams, a 26.4-48.0% and 21.0-42.5% decrease in TPC was observed in samples stored at 25 \({}^{\circ}\)C and 4 \({}^{\circ}\)C, respectively [29]. Other researchers noted 17.6 and 36.8% TPC losses in strawberry jams after 28 days of storage at 4\({}^{\circ}\) and 15 \({}^{\circ}\)C, respectively [26]. During confiture or jam cooking, the cellular structure is disrupted and the raw material becomes susceptible to non-enzymatic oxidation, which can be one of the main causes of loss of phenolic compound content. On the other hand, the heat treatment used during the processing of jams or confitures can cause structural changes that ultimately translate into greater bioavailability of polyphenols [29].  
\begin{table}
\begin{tabular}{l c c c c} \hline \multirow{2}{*}{**Confitures**} & **Days of Storage** & **Ascorbic Acid** & **TPC** & **HMF** \\  & **Storage** & **(mg/100 g)** & **(mg GAE/100 g)** & **(mg/100 g)** \\ \hline \multirow{3}{*}{From Thermomix (Normal Pressure)} & 0 & 23.7 \(\pm\) 0.4 \({}^{\text{aA}}\) & 431 \(\pm\) 6 \({}^{\text{aB}}\) & 0.55 \(\pm\) 0.01 \({}^{\text{cA}}\) \\  & 30 & 18.5 \(\pm\) 0.2 \({}^{\text{bB}}\) & 350 \(\pm\) 3 \({}^{\text{bB}}\) & 0.59 \(\pm\) 0.01 \({}^{\text{aA}}\) \\  & 120 & 11.2 \(\pm\) 0.3 \({}^{\text{cB}}\) & 335 \(\pm\) 8 \({}^{\text{bCA}}\) & 0.63 \(\pm\) 0.04 \({}^{\text{aA}}\) \\  & 180 & 6.1 \(\pm\) 0.2 \({}^{\text{dB}}\) & 322 \(\pm\) 9 \({}^{\text{cA}}\) & 0.67 \(\pm\) 0.05 \({}^{\text{aA}}\) \\ \hline \multirow{3}{*}{From Vacuum (E evaporator (Lowered Pressure))} & 0 & 23.5 \(\pm\) 0.7 \({}^{\text{aA}}\) & 501 \(\pm\) 7 \({}^{\text{aA}}\) & 0.14 \(\pm\) 0.01 \({}^{\text{aB}}\) \\  & 30 & 20.8 \(\pm\) 0.4 \({}^{\text{bA}}\) & 378 \(\pm\) 4 \({}^{\text{bA}}\) & 0.15 \(\pm\) 0.01 \({}^{\text{aB}}\) \\ \cline{1-1}  & 120 & 17.6 \(\pm\) 0.3 \({}^{\text{cA}}\) & 351 \(\pm\) 7 \({}^{\text{cA}}\) & 0.16 \(\pm\) 0.01 \({}^{\text{aB}}\) \\ \cline{1-1}  & 180 & 12.4 \(\pm\) 0.2 \({}^{\text{dA}}\) & 332 \(\pm\) 3 \({}^{\text{dA}}\) & 0.17 \(\pm\) 0.01 \({}^{\text{aB}}\) \\ \hline \end{tabular}  
* TPC—total phenolic content; HMF—hydroxymethyloffurfurral; values in the same column marked with different small letters are significantly different (\(p<0.05\)) and concern changes during storage for specific production method; values in the same column marked with different capital letters are significantly different (\(p<0.05\)) and concern data comparison between processing methods for specific day of storage.  
\end{table}
Table 2: Impact of processing methods and storage time on the bioactive compounds content in blue honeysuckle berry confitures.