## 3 Results
### Characterization of Permeates and Retentates
#### 3.2.1 Physicochemical Properties
\begin{table}
\begin{tabular}{c c c c c c} \hline  & **ACJ** & **PUF** & **RUF** & **PDF** & **RDF** \\ \hline TSS (°Brix) & 12.4 \(\pm\) 0.0 1  & 9.6 \(\pm\) 0.0 1  & 10.4 \(\pm\) 0.0 2  & 6.8 \(\pm\) 0.0 3  & 8.1 \(\pm\) 0.0 4  \\ Glu (g\(\cdot\)100 g\({}^{-1}\)) & 2.1 \(\pm\) 0.1  & 1.6 \(\pm\) 0.1 5  & 1.7 \(\pm\) 0.1 6  & 1.5 \(\pm\) 0.1 7  & 1.2 \(\pm\) 0.1 8  \\ Fru (g\(\cdot\)100 g\({}^{-1}\)) & 7.0 \(\pm\) 0.1  & 5.1 \(\pm\) 0.1 8  & 5.8 \(\pm\) 0.1 9  & 3.9 \(\pm\) 0.1 1  \\ TS (g\(\cdot\)100 g\({}^{-1}\)) & 9.8 \(\pm\) 0.2  & 7.3 \(\pm\) 0.1 8  & 7.5 \(\pm\) 0.2 9  & 6.7 \(\pm\) 0.2 1  & 5.7 \(\pm\) 0.2 1  & 5.7 \(\pm\) 0.2 1  \\ NSS (\%) & 2.6 \(\pm\) 0.0 1  & 2.3 \(\pm\) 0.0 1  & 2.9 \(\pm\) 0.0 2  & 0.1 \(\pm\) 0.0 1  & 2.4 \(\pm\) 0.0 1  \\ D (g\(\cdot\)mL\({}^{-1}\)) & 1.049 \(\pm\) 0.000  & 1.038 \(\pm\) 0.00 1  & 1.041 \(\pm\) 0.00 2  & 1.031 \(\pm\) 0.00 2  \\ pH & 3.4 \(\pm\) 0.0 2  & 3.5 \(\pm\) 0.0 1 8  & 3.5 \(\pm\) 0.0 1 8  & 3.4 \(\pm\) 0.0 1 8  & 3.4 \(\pm\) 0.0 1 8  \\ TA (g\(\cdot\)100 2) & 0.7 \(\pm\) 0.01  & 0.53 \(\pm\) 0.01 8  & 0.57 \(\pm\) 0.01 8  & 0.47 \(\pm\) 0.01 8  & 0.39 \(\pm\) 0.01 8  \\ TPC (mg GA\(\cdot\)100 g\({}^{-1}\)) & 11.66 \(\pm\) 3.2 5  & 90.1 \(\pm\) 5.4 8  & 112.5 \(\pm\) 4.5 8  & 85.3 \(\pm\) 3.5 9  & 93.6 \(\pm\) 2.3 8  \\ DPPH (\%) & 50.6 \(\pm\) 2.5  & 34.8 \(\pm\) 0.9 8  & 43.8 \(\pm\) 1.9  & 31.1 \(\pm\) 1.6 8  & 36.6 \(\pm\) 1.0 1 8  \\ Color parameters L* & 59.9 \(\pm\) 3.6 1  & 93.6 \(\pm\) 0.1 5  & 58.0 \(\pm\) 1.1 1  & 94.5 \(\pm\) 0.1 8  & 63.3 \(\pm\) 0.1 8  \\ a* & 18.4 \(\pm\) 0.8 1  & 6.4 \(\pm\) 0.1 1 8  & 17.0 \(\pm\) 0.3 1 8  & 6.1 \(\pm\) 0.0 1 8  & 13.4 \(\pm\) 0.1 8  \\ b* & 37.1 \(\pm\) 0. Above described results suggest that RUF sample was the most attractive from the point of view of reduced sugars content, but not reduced TPC, not changed color parameters, and radical-scavenging capacity reduced only by 13%. The presence of polyphenols in apple juice is considered one of the factors affecting products instability (changes in aroma and color). It has been shown that among the main negative changes, which take place in raw fruit materials during processing, there are oxidative polyphenol conversions and polymerization of products of oxidative reaction [32]. Polyphenols are susceptible to dehydrogenation by polyphenol oxidases in the presence of oxygen to form unstable quinones. These compounds are responsible in further reactions (e.g., interactions with proteins and polymerization) for development of dark-colored pigments [33]. During conventional apple juice processing, including UF clarification, polyphenols are removed to obtain clear juice with an adequate level of stability [34]. However, polyphenols are also described as key components of apples having a cardioprotective effect, antioxidant ability, ability to prevent oxidation of high-density lipids, remove low-density lipids and fight against ulcer and cancer [5; 24]. In addition, there is also emerging evidence that coingestion of polyphenols with other whole food components, such as fibre, can improve their bioavailability and bioefficacy [5]. In recent years, the interest of consumers and producers for bioactive compounds, especially phenolic compounds from natural sources, has increased remarkably [35]. Therefore, in the current approach of production of value-added cloudy apple-cranberry juice, the presence of polyphenols in the final product has to be considered as favorable. As was presented above, the difference in TPC between ACJ and RUF was statistically not significant, while in RDF the concentration of TPC was significantly lower than in ACJ. According to [PERSON] et al. [36] UF of apple juice with the use of 10 kDa membrane retained 28% of TPC, which explained the improvement of color after UF (final product in this traditional approach is permeate).