As temperature increased from 100 to 120 °C, the color of the extract became darker(Fig. 3a)
while the color of the residual potato peels became lighter (Fig. 3b).
At high temperatures (140 to 180 °C), higher concentrations of phenolic compounds were recovered and color of the extract was found to be even darker (Fig. 3a)
than at lower extraction temperatures. But, at temperatures of 180 to 240 °C, the color of the extract becomes very dark (low content of phenolic compounds).