Metabolic profiling of Peperoni di Senise PGI bell peppers with ultra-high resolution absorption mode Fourier transform ion cyclotron resonance mass spectrometry

Bell peppers (genus Capsicum) are an excellent source of health-related compounds, such as ascorbic acid (vitamin C), carotenoids (provitamin A), tocopherols (vitamin E), flavonoids and capsaicinoids. These compounds are known for their biological activities, including antioxidant, anti-inflammatory and anticarcinogenic properties. Over the past decade, there has been an increasing number of studies focused on metabolite profiling of bell peppers. However, none of the direct analysis methods exploited in these studies were capable of simultaneously detecting compounds belonging to more than four metabolite classes (and possible derivatives of model compounds) present in bell peppers, i.e. mainly amino acids, sugars, polyphenols and organic acids. We have attempted to profile a higher number of metabolite classes by performing a direct-injection analysis with a Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), on Peperoni di Senise bell peppers (Capsicum annuum L.). These bell peppers are a typical food product cultivated in Basilicata (Southern Italy), protected with a protected geographical indication (PGI) quality mark and known for their unique taste. To increase the performance of the FT-ICR MS method, we processed the recorded time-domain ion signals (transients) into the absorption mode FT-ICR mass spectra. The latter was achieved by the use of the dedicated software package, AutoVectis Pro. Mass spectral representation in absorption mode produced a more comprehensive description of the metabolic profile of Peperoni di Senise PGI by improving results reliability via artifacts removal and identifying a higher number of compounds.