Mixture contour plot of total flavonoids content (TFC).
Flavonoids are polyphenols with diphenylpropane (C6C3C6) skeletons.
They are considered to be the largest group of naturally
occurring phenols (Vijayakumar et al., 2008).
In general, flavonoids structures are less polar compared with
phenolic acid. The result of Fig. 2 revealed that the contents of raw
flavonoids extract also increases with the concentration of acetone.
Flavonoids are usually stored in the vacuoles of the cell; therefore,
solvent molecule must be able to penetrate the cell walls to
get to the compounds of interest. Flavonoids glycosides are more
water soluble and thus require the use of relatively polar solvent
(De la rosa et al., 2010).
Acetone interacts with the flavonoids probably through noncovalent
interactions and promotes a rapid diffusion into the
solution (Luque de Castro and Tena, 1996). The optimal extraction
yield may be fulfilled when the polarity of the fluid and its
flavonoids are coincident.
The results indicated that the optimal acetone concentration for
extraction flavonoids was found to be 61%. The highest yields of
flavonoids were obtained with acetone–water (61:38, v/v).
Comparison of all solvent systems evaluated in this study
revealed acetone (50–70%, v/v) to be the optimum extraction
medium both with regard to TPCs and TFCs from capsicum byproduct