Of the coloured-flesh tuber varieties studied, the samples contained
from 2.47 to 4.27 mg GA/gDM of total polyphenols (Table 1).
The highest content of those compounds was found in tubers of the
Blue Congo variety and the lowest content in Herbie 26 potatoes.
Experimental flour manufactured from purple and red-fleshed
potatoes of the four varieties studied contained from 36% (Herbie
26) to 68% (Blue Congo) less total polyphenols compared to the
raw material, and the highest loses were found in the flour from
the purple-fleshed Blue Congo and Valfi varieties.