Determination of fourteen polyphenols in pulses by high performance liquid chromatography-diode array detection (HPLC-DAD) and correlation study with antioxidant activity and colour.

Pulses, which include lentils, beans, chickpeas, peas, and soybeans, provide an important source of proteins, dietary fibers, minerals and vitamins, as well as such important bioactive molecules as polyphenols. The presence of polyphenols is often related to the colour of the pulse and to its antioxidant activity. The aim of this work was to set up a new HPLC-DAD method for simultaneously analysing 14 polyphenolic compounds, including two anthocyanins, in different varieties of pulses and to correlate the polyphenol content with the seed coat colour and the antioxidant activity. The total content of the analysed polyphenols ranged from 3mg/kg for dehulled red lentils to 1630.5mg/kg for ruviotto beans. Samples with dark testa (or seed coat), namely black lentils and diavoli beans, had higher antioxidant activity than those with pale testa, and a positive correlation was found between total phenolic content (TPC) and IC50 for dark coloured varieties.