# Concentrations of Beetroot (_Beta vulgaris_ L.) Peel and Flesh Extracts by Reverse Osmosis Membrane
## 3 Results
### Thermo-Instability of Betalains (Color Compounds)  
Variations of betalains in the feeds and final concentrates with heating time (0-90 min) at 70 \({}^{\circ}\)C are shown in Table 4. In the reentate of peel extract, the amounts of BC, BX, and TBC were reduced a bit more than in feed after 90 min of heating. In contrast, improvements in the recovery of BC, BX, and TBC were experienced in the reentate of flesh compared to the feed. Table 5 reveals the color diversity of beetroot flesh and peel extracts before and after heat treatment at 70 \({}^{\circ}\)C for 90 min. It is shown in Table 5 that the membrane filtration has some influence on the tonality of the extracts, and the variations depend upon the type of extract, whether it is peel or flesh. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**Moisture (\%)**} & \multirow{2}{*}{**Dy Matter**} & \multirow{2}{*}{**Dy Matter**} & \multirow{2}{*}{**Yield (\%)**} & \multirow{2}{*}{**Density**} \\  & & & & & & & \\ \hline \multirow{2}{*}{Flesh} & Initial & 99.6 & 0.4 & 0.004 & 3.44 & 0.9998 & 0.02 \\  & Final & 97.75 & 2.25 & 0.023 & 19.57 & 1.0073 & 4.1 \\ \hline \multirow{2}{*}{Peel} & Initial & 99.91 & 0.09 & 0.001 & 0.55 & 0.9992 & 0.1 \\  & Final & 98.5 & 1.5 & 0.015 & 9.11 & 1.0039 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Characteristics of the beetroot flesh and peel extracts before and after the concentration by RO membrane (X20). Values of t\({}_{1/2}\) and k of the betalains in feed and concentrates of peel and flesh extracts are listed in Table 6. In general, the peel extract revealed a greater t\({}_{1/2}\) value than the flesh extract both before and after filtration. The improvements in thermal stability after the membrane filtration are proven by the increased t\({}_{1/2}\) values. There are not many such differences for the values of k among the extracts of feed or retentate. CRs of betalains in the beetroot flesh and peel extracts are presented in Figure 7a,b, respectively. In the case of flesh extract, the drastic changes in CR of betalains appeared between the heating times of 30 min and 45 min. The CR of betalains in beetroot peel extract dropped significantly after 30 min of heating time. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**L\({}^{\bullet}\)**} & \multirow{2}{*}{**a\({}^{\bullet}\)**} & \multirow{2}{*}{**b\({}^{\bullet}\)**} & \multirow{2}{*}{**C\({}^{\bullet}_{\text{ab}}\)**} & \multirow{2}{*}{**Hue\({}^{\circ}\)**} & \multirow{2}{*}{**\(\Delta\)E\({}^{\bullet}_{\text{ab}}\)**} & \multirow{2}{*}{**BI**} \\  & & & & & & & & \\ \hline \multirow{2}{*}{Fesh} & before heat & 27.14 \(\pm\) 0.31 & 30.91 \(\pm\) 0.92 & 32.57 \(\pm\) 1.87 & 46.47 \(\pm\) 0.81 & 44.91 \(\pm\) 1.99 & 43.03 \(\pm\) 0.21 & 82.24 \(\pm\) 1.84 \\  & \
\begin{tabular}{c} after heat \\ treatment \({}^{\text{\text{\text{\text@b{}}}}}\) \\ \end{tabular} & 17.04 \(\pm\) 0.87 & 35.11 \(\pm\) 1.31 & 28.56 \(\pm\) 1.44 & 39.11 \(\pm\) 0.45 & 43.8 \(\pm\) 4.44 & 54.04 \(\pm\) 0.34 & 128.97 \(\pm\) 1.74 \\ \hline Peel & before heat & 4.12 \(\pm\) 0.06 & 14.11 \(\pm\) 0.05 & 6.74 \(\pm\) 0.04 & 25.53 \(\pm\) 0.14 & 15.64 \(\pm\) 0.06 & 65.28 \(\pm\) 0.05 & 172.65 \(\pm\) 1.38 \\  &
\begin{tabular}{c} after heat \\ treatment \({}^{\text{\text{\text@b{}}}}\) \\ \end{tabular} & 4.61 \(\pm\) 0.44 & 9.81 \(\pm\) 0.19 & 6.4 \(\pm\) 0.29 & 33.09 \(\pm\) 0.72 & 11.71 \(\pm\) 0.32 & 64.69 \(\pm\) 0.33 & 134.46 \(\pm\) 5.28 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Values of L\({}^{\bullet}\), a\({}^{\bullet}\), b\({}^{\bullet}\), C\({}^{\bullet}_{\text{ab}}\), Hue\({}^{\circ}\), \(\Delta\)E\({}^{\bullet}_{\text{ab}}\), and BI of the beetroot flesh and peel concentrations before and after heat treatment.