## 3 Results
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample** & \multicolumn{2}{c}{**TPC * of TACs**} & \multicolumn{2}{c}{**TPC of TLCs**} & \multicolumn{2}{c}{**TPC of TLs**} \\ \hline  & min–Max value & Median value & min–Max value & Median value & min–Max value & Median value \\ \hline Apple juice (mg/100 mL juice) & 10.1–19.3 & 16.8 & 2.4–17.8 & 3.4 & 13.6–17.8 & 19.1 \\ \hline Apple by-products (mg/100 g by-products) & 7.4–21.2 & 13.2 & 1.2–14.4 & 2.6 & 8.7–27.6 & 23.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Total phenolic content of TAC, TLC, TL extracts of apple juice and by-products. It is generally known that the primary barriers to the practical use of polyphenols are their low bioavailability and restricted water solubility [17]. More specifically, polyphenols are a diverse group of compounds found mainly in plant-related sources, and their solubility can vary based on their specific structure. Generally, polyphenols are more soluble in alcohol and less soluble in water and lipids. Many low-molecular-weight polyphenols, such as flavonoids, can be somewhat soluble in water, with low solubility, however, while larger polyphenic compounds tend to have much lower solubility in water. Moreover, polyphenols are also generally not well soluble in lipid systems. They are more polar compounds than the classic non-polar organic solvents used for lipid solutions, which means they do not dissolve well in these solvents. However, several lipid soluble polyphenols exist from several sources and with high bioactivity [18]. In addition, during a counter current distribution separation process some polyphenols of high molecular weight may be trapped within lipophilic mixtures and thus a small proportion of polyphenols may be dispersed in the lipophilic phase of extraction processes too. Finally, polyphenols are typically soluble in alcohol, especially in ethanol and methanol, like the 87% ethanol in water solution that was chosen for the applied counter current methodology. This solubility is often utilized in the extraction of polyphenols from plant materials [19]. More specifically, polyphenols are primarily soluble in alcoholic solutions of methanol or ethanol, with variable low solubility in water and much lower solubility in lipids apart from some lipid soluble phenolics. In alcoholic solutions, phenolics are better solubilized in the presence of low amounts of water and higher amounts of alcohol, with optimum solutions being those of 60-70% of alcohol in water (\(v/v\)), which, however, is not the optimum solvent for co-extracting other amphiphilic compounds. However, an 87% ethanol in water solvent that also shows very close to optimum conditions for phenolics recovery [7; 9] also facilitates at the same time the co-extraction of not only phenolics but several other important amphiphilic compounds too like carotenoids and polar lipids within the same extract [7; 9; 10; 11], and that is why it was chosen for the present study. Within the present study, a counter current distribution was applied with the most optimum solvents for the dissolution, extraction and separation of the more polar TACs from the more non-polar TACs, meaning 87% ethanol in water \(v/v\) (mainly for obtaining phenolics and polar lipids), versus the more non-polar solvent, petroleum ether, which was the solvent used for acquiring the most lipophilic compounds from these TL extracts during this counter current distribution separatory procedure.