Phytochemical characterisation of green beans (Phaseolus vulgaris L.) by using high-performance liquid chromatography coupled with time-of-flight mass spectrometry.

Introduction: Although green beans (Phaseolus vulgaris L.) constitute a major agro-industrial crop worldwide and involve many bean varieties, the phytochemical composition and how this fluctuates among varieties is not well known.

Objective: The purpose of this work was to conduct a comprehensive characterisation of the phytochemical compounds found in three varieties of green bean.

Methodology: Hydromethanol extracts from green beans were analysed by high-performance liquid chromatography (HPLC) coupled with electrospray time-of-flight mass spectrometry (ESI-TOF-MS) in order to characterise phytochemical compounds from different varieties of P. vulgaris L. The compounds were characterised based on interpreting their mass spectrum provided by the TOF-MS as well as by comparison with information from the literature (some compounds have been described previously in Fabaceae).

Results: In this work, 72 phytochemical compounds were tentatively characterised by HPLC-ESI-TOF-MS. These compounds were classified as, 10 phenolic acids, 59 flavonoids, two lignans and an iridoid. Notably, out of the 72 compounds, 54 are new and their isomers have been characterised for the first time in green beans.

Conclusion: The phytochemical composition of three different varieties of P. vulgaris L have been characterised using HPLC-ESI-TOF-MS. A total of 72 phytochemical compounds were characterised, 54 being reported in green beans for the first time. Among these were the main flavonoids detected. These results highlight the influence that variety can exert on the quality of phytochemicals. Given that new phytochemical compounds have been characterised, this study offers a useful approach for improving and updating the food-composition tables.