The results of the Folin-Ciocalteu assay are shown in Table 2. Purple potato cultivars were a richer source of polyphenols than red potato varieties. Among purple tuber varieties Vitelotte variety had the highest gallic acid equivalents (135.2 mg 100 g−1 FW, respectively), followed by Balue St. Galler, Blue Congo and Blaue Elise varieties (101.2, 95.8 and 84.1 mg 100 g−1 FW, respectively).