Optimization of an extraction method for the simultaneous quantification of sixteen polyphenols in thirty-one pulse samples by using HPLC-MS/MS dynamic-MRM triple quadrupole

Pulses are an important source of proteins, carbohydrates, and dietary fibre, and also contain polyphenols, which are bioactive compounds with antioxidant activity. A new analytical method that uses high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for the quantification of sixteen polyphenols in thirty-one pulse varieties. Different extraction procedures were tested (acidic hydrolysis, alkaline hydrolysis and extraction without hydrolysis), and acidic hydrolysis at pH 2, extraction temperature of 20 °C and extraction time of 2 h was proven to be the best in terms of recovery percentages (99.7-107.6%). The highest polyphenol levels were found in beans, particularly black beans (459 mg kg−1) and ruviotto beans (189 mg kg−1); significant levels of polyphenols were also observed in lentils, particularly black lentils (137 mg kg−1) and quality gold lentils (132 mg kg−1). This study provides new information about legume polyphenols, offering reasons to promote legumes as part of a healthy diet.