Rapid determination of free anthocyanins in foodstuffs using high performance liquid chromatography

Anthocyanins constitute a major group of natural pigments, and they are responsible for the colours of fruits and vegetables. A rapid and feasible assay procedure for the determination of free forms of the six most abundant anthocyanins in foods is described. The 3-glucoside forms of pelargonidin, cyanidin, peonidin, delphinidin, petunidin and malvidin with the aglycone cyanidin (as internal standard) were separated by gradient elution and quantified using HPLC-DAD within 18 min. A fast sample preparation step was employed which allows direct injection of samples to the chromatograph without need of chemical extraction. Testing on 28 different vegetable, fruit and processed commercial product samples demonstrated applicability in the concentration range of about 80–420 ng/mL with an accuracy of 99.2 ± 0.2% and an average precision of 0.8%. The method was suggested as a cheap and robust alternative to the previous ones that employ multi-step sample treatment protocols.