Estimation of the global composition of Malvar grape seeds was
done on the basis of peak area, assuming that the area of the whole
chromatogram was equivalent to 100% of the constituents
absorbing at 280 nm. For simplicity, all peaks were divided into
5 groups: flavan-3-ols, hydroxybenzoic compounds, hydrolysable
tannins (gallo- and ellagitannins), others (tryptophan, methylgallate
and dihydroflavonols) and unidentified compounds. The area
of di- and multicomponent peaks was divided by the number of
components and referred to each of them at equal amounts. This
allowed us to obtain an approximation to the global composition of
the grape seeds