jf9b04581_si_001.pdf (2.9 MB)
Mapping Taste-Relevant Food Peptidomes by Means of Sequential Window Acquisition of All Theoretical Fragment Ion–Mass Spectrometry
journal contribution
posted on 2019-09-30, 12:03 authored by Karin Sebald, Andreas Dunkel, Thomas HofmannDuring
the last few years, key taste-active compounds have been
isolated and identified by means of a combination of a time- and lab-consuming
successive fractionation and sensory characterization. Because the
peptidome of fermented, protein-rich food is very complex, new strategies
are necessary to accelerate the identification of taste-active peptides.
In this study, two advanced mass spectrometric approaches were developed
to comprehensively map the bitter tasting peptidome of fermented foods
by data-independent acquisition (DIA) using sequential window acquisition
of all theoretical fragment ion–mass spectrometry (SWATH–MS)
and an in silico-assisted triple quadrupole (QQQ)-based
targeted proteomics approach, separately. Application of both techniques
on two fresh cheese samples as well as on crude medium-pressure liquid
chromatography fractions exhibiting intense bitter taste, followed
by filtering the hydrophobic target peptides (Q value
of ≥1200 cal/mol) showing a signal-to-noise ratio of ≥10
and a fold change of ≥3 when comparing the less bitter to the
more bitter cheese sample, revealed the candidate bitter peptides,
which were then validated by means of synthetic reference peptides
and human sensory evaluation. The bitter peptides were then quantitated
in the fresh cheese samples as well as in a series of dairy products
by means of QQQ–MS and SWATH–MS, separately. Although
the QQQ–MS method showed 2–80-fold lower limits of quantitation
(LOQ), the SWATH–MS method could be shown for the first time
to enable the comprehensive quantitation of all sensorially relevant
key bitter peptides with LOQs far below the bitter taste recognition
concentration of each peptide.