3.3. Water extract
There was no significant difference in the total phenolic contents
of water extract between green and red lentils from the whole seed,
hull and residue (Table 3). Furthermore, only the hull and residue
extracts showed significant differences in phenolic components when
comparing green and red lentils. Lentil hulls contained over three
times the total phenolic content and over twelve-fold the antioxidant
activity of the whole seed. The total phenolic content of hot water and
water extracts of the lentil hull were comparable to those extracted
from the lentil seed coat with methanol–water (1:1 v/v) (Ronzio et al.,
1998) (38–52 mg catechin equivalent/g sample dry weight). The
water extract of yellow pea hull, similar to its hot water extract, had
the lowest total phenolic, flavonol and anthocyanin contents.
Moreover, the yellow pea hull had only half the total phenolic
content, but exhibited antioxidant activity not different from those of
the whole seed or residue. The total phenolic content of pulse residue
was significantly (Pb0.0001) higher than those of the whole seed,
although that difference was not reflected in the antioxidant activity.
The high phenolic content of the residue corresponds to the higher
tannin content in the powder fraction compared to the raw seed
observed in dehulling the red lentil (Wang, 2008). Therefore, water
can be considered a viable solvent for extracting antioxidant
components only from the lentil hull.