A comprehensive characterisation of beer polyphenols by high resolution mass spectrometry (LC–ESI-LTQ-Orbitrap-MS)

Abstract

Beer is the second most consumed alcoholic beverage in Europe and shown by the European Prospective Investigation into Cancer and Nutrition cohort study to be the main food contributor to hydroxybenzoic acid intake. About 70-80% of the total polyphenol content in beer comes from malt, and the remaining 30-20% from hops. In this work, liquid chromatography coupled with an electrospray ionization hybrid linear ion trap quadrupole Orbitrap mass spectrometry technique has been used for an accurate identification of beer polyphenols. 47 phenolic compounds were identified using high mass accuracy and confirmed by MS(2) experiments, including simple phenolic acids, hydroxycinnamoylquinics, flavanols, flavonols, flavones, alkylmethoxyphenols, alpha- and iso-alpha-acids, hydroxyphenylacetic acids and prenylflavonoids. As far as we know, 7 of these compounds have been recognised in beer for the first time: feruloylquinic acid, caffeic acid-O-hexoside, coumaric acid-O-hexoside, sinapic acid-O-hexoside, catechin-O-dihexoside, kaempferol-O-hexoside, and apigenin-C-hexoside-pentoside.

Polyphenol analysis using high‐resolution mass spectrometry allows differentiation of drought tolerant peanut genotypes

“…All the ions showed COO [M−H−44] − loss in the tandem mass spectra. Moreover, vanillic acid had an extra fragmentation, losing the methyl group [M−H−15] − , a fact also reported in other studies . Protocatechuic acid‐ O ‐hexoside ( m / z 315.07230) and galloylglucose ( m / z 331.0664) were also identified and confirmed by MS/MS analyses.…”

“…(+)‐Catechin ( m / z 289.07235) and epicatechin ( m / z 289.07210), characterized by the same molecular ion [M−H−289] − and MS/MS fragmentation at m / z 245, m / z 205 and m / z 179, were found . Three isomers of catechin‐ O ‐hexoside ( m / z 451.12477), a flavanol in glycosylated form, were identified by the loss of sugar moiety [M−H−162] − in tandem mass spectra, as already reported . The polymeric form of flavanols was represented by two isomers of procyanidin dimer type A ( m / z 575.12005), three isomers of procyanidin dimer type B ( m / z 577.13592) and a procyanidin trimer type B ( m / z 865.19890; 0.419 ppm), all of them sharing the same characteristic, i.e.…”

Analgesic, Anti-Inflammatory, and Antioxidant Activities of Byrsonima duckeana W. R. Anderson (Malpighiaceae)

“…Further product ions at m/z 111, 93, and 85 reinforced this structure proposal [25]. Peak 2 ( R t 9.53 min) was tentatively identified as the gallic acid based on its deprotonated molecule at m/z 169 and the characteristic carbon dioxide loss (−44 Da), giving the fragment [M–CO 2 –H] − at m/z 125 [26]. The main peak ( 4 ), eluting at 20.37 min, was tentatively assigned as ethyl gallate based on its typical fragmentation ions ( m/z 197 → 169 and m/z 169 → 125), related to those observed for the gallic acid [17].…”

Lipidomics as an important key for the identification of beer-spoilage bacteria

“…The method that we used can be employed not only for identifying anaerobic beer‐spoiling bacteria in beer; it is much more versatile, as it makes it possible to determine any metabolites in beer provided one can find a suitable biomarker. LC–ESI‐LTQ‐Orbitrap‐MS can thus be used as a multipurpose technique, which was employed, for instance, to identify nearly 50 completely new phenolic compounds in beer including hexosides, dihexosides, pentosides and quinic conjugates (Quifer‐Rada ), to distinguish differential metabolites between regular and nonalcohol beers (Andres‐Iglesias et al . ) or to perform beer fingerprinting (Catharino et al .…”