Addition of water to solvent improves extraction rate, but too
high water content brought an increased concomitant extraction
of other compounds and, then to lower phenols concentrations
32.9 mg/L, in the extracts. In fact, Simple sugars and oligosaccharides
dissolve more easily in ethanol–water than in acetone–water.
This may be attributable to the higher solubility of proteins and
carbohydrates in water than in ethanol and acetone (Zielin´ ski and
Kozłowsk, 2000). The use of water in combination with organic solvents
contributes to the creation of a moderate polar medium that
ensures the extraction of phenolic compounds (Liyana-Pathirana
and Shahidi, 2006).
Another possible reason for the increased efficiency with a
presence of some water might be the increase in swelling of
plant material by water, which increased the contact surface area
between the plant matrix and the solvent (Xiao et al., 2008).