Fig. 1

UHPLC-DAD chromatograms of mixed standards (A) and bilberry extract before (C) and after acid hydrolysis (B). Mobile phase A—95 %:5 % water-formic acid; mobile phase B—95 % methanol:5 % formic acid (v/v); flow rate 1.0 mL/min; column: Phenomenex Kinetex PFP, 4.6 × 150 mm, 2.6 μm; detection at 520 nm; injection: 10 μL. A = standards: 1 delphinidin, 2 luteolinidin, 3 cyanidin, 4 petunidin, 5 pelargonidin, 6 peonidin, 7 malvidin; B = hydrolyzed bilberry extract; C = bilberry extract