We thank Dr. Carlos Arbizu, International Potato Center (Lima, Peru) for providing the mashua genotypes. This research was supported by the CUI project of the Cooperation Universi- taire au Developpement (CUD, Belgium), and by the Consejo Nacional de Ciencia y Tecnolog´ıa (CONCYTEC, Peru).

Qualitative high performance liquid chromatography with diode array detection (HPLC-DAD) was performed to characterize nonanthocyanin phenolic compounds in three different coloured mashua genotypes. The ORAC antioxidant activity contribution in the tubers related to the type of phenolic compounds present was also evaluated. Phenolic compounds were analysed by separating them into four main fractions: fraction I obtained by means of a liquid–liquid partition with ethyl acetate and fractions II, III and IV obtained by elution on a Sephadex LH-20 column. Fraction I revealed the presence of gallic acid, gallocatechin, procyanidin B2 and epigallocatechin. Other phenolic compounds such as hydroxycinnamic and hydroxybenzoic acid derivatives, rutin and/or myricetin derivatives were also present in fraction I. Fraction II was mainly composed of epicatechin, hydroxycinnamic and hydroxybenzoic ac...

We thank Dr. Carlos Arbizu, International Potato Center (Lima, Peru) for providing the mashua genotypes and Alexandrine During and Yves-Jacques Schneider for their suggestions in the discussion of this paper. This research was supported by the CUI project of the Belgian Coopération Universitaire au Développement (CUD, Belgium) and by the Consejo Nacional de Ciencia y Tecnología (CONCYTEC, Peru).