Ion-Mobility-Based Liquid Chromatography–Mass Spectrometry Quantitation of Taste-Enhancing Octadecadien-12-ynoic Acids in Mushrooms

Abstract

For the accurate quantitation of kokumi-enhancing and bitter-tasting octadecadien-12-ynoic and octadecadienoic acids in chanterelles (Cantharellus cibarius Fr.), a sensitive ultra-high-performance liquid chromatography−differential ion mobility spectrometry−tandem mass spectrometry method was developed. On the basis of these quantitative data and the taste thresholds, dose-over-threshold factors were calculated to determine the contribution of these sensometabolites to the kokumi and bitter taste of chanterelles; e.g., 14,15-dehydrocrepenynic acid (3) and (9Z,15E)-14-oxooctadeca-9,15-dien-12-ynoic acid (7) were identified as key kokumi substances in raw chanterelles. Quantitative profiling of these compounds in various mushroom species demonstrated a unique accumulation of octadecadien-12-ynoic acids in Cantharellus. Furthermore, storage experiments highlighted dynamic processes, including the biosynthesis of these substances as a result of lipid peroxidation mechanisms.

Quantification and Bitter Taste Contribution of Lipids and Their Oxidation Products in Pea-Protein Isolates (Pisum sativum L.)

“…Additionally, the DMS technique was implemented to overcome the mass transitions’ spectral overlap 295.1 → 171.0 for 9-HODE isomers 5 and 6 and 295.1 → 195.0 for 13-HODE isomers 7 and 8 , respectively. In the past, DMS had already been used to enhance the selectivity for analyzing isobaric and isomeric substances. ,,, …”

“…In the DMS cell, the SV shifts the ion trajectories in the DMS cell and prevents the ions from entering the MS/MS system. This voltage is negated by the CoVa compound-specific parameter that compensates for the SV-dependent shift of an ion trajectory for specific ions to enter the MS. Several parameters, for example, the temperature or the use and type of a chemical modifier, affect the DMS cell’s gas equilibrium. ,,− Based on Mittermeier et al (2020), each parameter’s optimization was performed on the column individually . Accordingly, each HODE isomer ( 5–8 ) was injected separately into the UHPLC–DMS–MS/MS system, and the CoV was ramped from −30 to 15 V for a fixed set of SVs (500, 1000, 1500, 2000, 2500, 3000, and 3500 V).…”

“…Although the key bitter molecules of pea-protein isolates have been identified, exact quantitative data to evaluate each substance’s overall taste contribution are still missing. The challenge with this was to determine the accurate MS/MS-based quantification of target compound isomers, such as E,Z - and E,E -hydroxyoctadecadienoic acids (HODEs), which mainly relied on their chromatographic separation previously. , In the past, the spectral overlap of isobaric and isomeric analytes could be overcome by introducing differential ion mobility (DMS) into the field of lipidomics. − Within the DMS cell, the separation voltage (SV) is applied perpendicular to the transport gas flow and prevents the ions, which are transmitted through the DMS cell by the transport gas, from entering the MS. The compensation voltage (CoV)a compound-specific parametercounteracts the ion shifts caused by the SV and causes the specific ions to pass the DMS cell into the MS.…”

“…The compensation voltage (CoV)a compound-specific parametercounteracts the ion shifts caused by the SV and causes the specific ions to pass the DMS cell into the MS. This CoV can be optimized as an additional, third separation parameter (besides the retention time and MRM transition) for isomeric and isobaric compounds. ,,− …”

Mass Spectrometry for Analysis of Changes during Food Storage and Processing

“…31 The use of ion mobility devices provides an additional separation dimension for resolving complex chemical mixtures with structural similarity. Mittermeier et al developed a LC−ESI−IMS method for quantitation of sensometabolites in chanterelles and other mushrooms, 32 in which nitrogen was used as the carrier gas and 2-propanol was used as the gas modifier during the IMS analysis. The study found that octadecadien-12-ynoic acids, especially (10E,14Z)-9-hydroperoxy-10,14-octadecadien-12-ynoic acid, are the major taste-modulating compounds in chanterelles, which were strongly affected by storage and thermal treatment.…”