As shown in Table 4, the highest losses of polyphenolic compounds
were observed in snacks produced without the experimental
flour (43% loss compared to the dough before extrusion). The
total losses of polyphenols in snacks enriched with flour from coloured-
fleshed potatoes, as a result of dough extrusion and frying,
ranged from 25% (Salad Blue and Herbie 26) to 34% (Valfi). The
most polyphenols were found in the products supplemented with
flour from Blue Congo potatoes. These results suggest that the
polyphenols present in tubers of coloured-fleshed varieties are better
stabilised during thermal processes than polyphenolic compounds
in potatoes of traditional coloured flesh. These
differences also depended on potato variety and on the polyphenolic
profile.