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

Abstract

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.

Keywords: (−)-Epicatechin (PubChem: CID 72276); 3,5-di-O-Caffeoylquinic acid (PubChem: CID 6474310); Caffeic acid (PubChem: CID 689043); Catechin (PubChem: CID 73160); Chlorogenic acid (PubChem: CID 1794427); Cyanidin 3-glucoside chloride (PubChem: CID 197081); Delphinidin 3,5-diglucoside chloride (PubChem: CID 10100906); Extraction methods; Ferulic acid (PubChem: CID 445858); Gallic acid (PubChem: CID 370); HPLC-MS/MS; Kaempferol 3-glucoside (PubChem: CID 25203515); Polyphenols; Pulses; Quercetin (PubChem: CID 5280343); Rutin (PubChem: CID 5280805); Shikimic acid (PubChem: CID 8742); Syringic acid (PubChem: CID 10742); Triple quadrupole; Vanillic acid (PubChem: CID 8468); p-Coumaric acid (PubChem: CID 637542).