## 3 Results
### Phenols Profile and Storage Stability
The 14-day storage of microcapsules at 4 \({}^{\circ}\)C in a dark room did not affect the quality profile of the phenolic compounds but decreased their concentration (Table 5). For microcapsules with a CE core, the phenolic compounds were reduced compared to the sample before storage by 8.92 (D) to 18.33% (C), while for microcapsules with a PE core by 11.79 (H) to 23.98% (F). The recorded values were lower compared to the extracts themselves\(-\)for CE, a decrease of 21.92%, and for PE, a decrease of 20.52%. In both cases, the highest stability of phenolic compounds was ensured by the crosslinking mixture Alg + Pect + WPI, while the lowest was seen in the case of Alg + Pect. The same pattern was observed in the group of dominant compounds present in the microcapsules\(-\)anthocyanins. After 14 days of storage, a decrease in the concentration of anthocyanins in the CE microcapsules was observed, ranging from 6.50 (B) to 18.37% (C) and from 11.60 (H) to 24.29% (F) for the PE microcapsules. The effect of the encapsulation process and storage of the finished microcapsules on the change in the phenolic profile of blueberry extracts has not been assessed so far. The cationic flavylium form of anthocyanins, the main phenolic fraction of blueberry fruit, is very sensitive to oxygen, time, light, temperature, and pH, quickly degrading into colorless aldehydes and phenolic acids [38]. Hence, there is a need to improve the stability of these compounds, which can be achieved, among others, via microencapsulation. It was previously found that the main reason for the reduced concentration of anthocyanins in microcapsules is their hardening and diffusion into the CaCl\({}_{2}\) solution [8]. At the same time, it was suggested that the enrichment of Alg in polysaccharides and protein may result in better preservation of anthocyanins, which was achieved in this work after adding Pect and WPI. The diffusion of anthocyanins into the curing solution is mainly related to the porosity of microcapsules. Therefore, additional carboxyl and amino groups in the polymerization mixture led to an increase in the gelation rate of the polymers and a reduction in the diffusion of anthocyanins into the crosslinking solution due to the decreased porosity after the formation of the hydrogel. The same relationship was demonstrated by [PERSON] et al. [39] for the commercial anthocyanin fraction of blueberries encapsulated with WPI and various polysaccharides. After 35 days of storing the microcapsules under refrigerated conditions, the lowest decrease in anthocyanin concentration was noted for the WPI and Pect complex (26%). These results indicate that the enrichment of Alg with protein and additional polysaccharides is an effective method of reducing the losses of phenolic compounds, mainly anthocyanins, both during the encapsulation process and subsequent storage of the finished product. However, in the works in which microcapsules were developed by spray drying, where maltodextrin, inulin and gum Arabic were used as the encapsulating agents of blueberry extract, a decrease in anthocyanin content was demonstrated in the range from 4.45 to 13.77% after 30 days of storage at different temperatures [21]. The cited data indicate a higher efficiency of maintaining anthocyanin stability in microcapsules obtained by spray drying than ionotropic gelation. Hence, there is a need to improve this method in order to reduce the losses of bioactive compounds during the storage of the obtained microcapsules. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**No.