Quantitative Proton NMR Spectroscopy for Basic Taste Recombinant Reconstitution Using the Taste Recombinant Database

Abstract

The quantitative determination of putative taste active metabolites, the ranking of these compounds in their sensory impact based on dose-overthreshold (DoT) factors, followed by confirmation of their relevance by reconstitution and omission experiments enables the decoding of the non-volatile sensometabolome of certain foods. The identification and quantitation of target taste compounds by liquid chromatography-tandem mass spectrometry (LC-MS/MS), high-performance liquid chromatographyultraviolet/visible (HPLC-UV/Vis) spectroscopy, or high-performance ion chromatography (HPIC) is often laborious and timeconsuming. In this work, we present a novel quantitative 1 H NMR approach for reconstituting basic taste recombinants of different foods, including apple juice, balsamic vinegar, golden chanterelles, process flavor, and shrimp. Compound identification using the taste recombinant database, followed by absolute quantitation via quantitative 1 H NMR (qHNMR), enables a fast and direct reconstitution of basic taste recombinants. The taste profile analysis of basic taste recombinants was generated via qHNMR in less than 15 min and compared with literature data acquired by LC-MS/MS and/or HPLC-UV/Vis and revealed identical results for all taste qualities. A determination of limit of detection (LoD) values for S/N = 50 of various proton signals with different integrals and multiplicities demonstrated that taste recognition thresholds of all basic tastants are far above those of LoD concentrations under the chosen conditions. Therefore, our experimental setup is able to detect basic taste-active compounds well below their taste recognition thresholds.

Sensoproteomic Discovery of Taste-Modulating Peptides and Taste Re-engineering of Soy Sauce

“…The remaining taste qualities were perceived less intense (sweet: average intensity 1.0, sour: average intensity 1.3, and kokumi: average intensity 1.7), as they were strongly masked by the key taste qualities. To investigate the impact of literature-known basic taste compounds on the overall taste profile of the different soy sauces, amino acids, nucleotides and nucleosides, minerals, carbohydrates, organic acids, and quaternary ammonium compounds were determined in the desalinated soy sauces dissolved in methanol/water (30:70, v/v).…”

“…Thereby, anions and cations were investigated by high-performance ion chromatography (HP–IC) and quantified by external calibration. The analyzed saccharides, organic acids, and quaternary ammonium compounds were determined by means of qNMR using the in-house NMR database . Free L-amino acids, nucleotides, nucleosides, γ-glutamyl peptides, arginyl peptides, and pyroglutamyl peptides were quantified by means of LC–MS/MS using isotopically labeled internal standards (ISs) and stable-isotope dilution analysis (SIDA) or external calibration.…”

Identification and Quantitation of Taste-Active Compounds in Dried Scallops by Combined Application of the Sensomics and a Quantitative NMR Approach

“…Besides the conventional methodology for the quantitation of taste-active compounds using UHPLC–MS/MS, a novel approach by means of the direct analysis of taste-active organic compounds in a food extract using qHNMR was applied. , To enable the identification of taste-active compounds, a 1 H NMR reference database was created by conducting standardized 1 H NMR acquisitions of general taste-active compounds (e.g., amino acids, nucleotides, and organic acids) as well as seafood-specific taste-active compounds (e.g., QACs and opines). The identification was then performed by comparing specific proton signals in the 1 H NMR spectrum of the reference sample with the 1 H NMR spectrum of the DSE.…”

“…21 This approach relies on the creation and application of an in-house 1 H NMR database of the literature-known organic taste and tastemodulating compounds in order to identify and quantify these compounds even in complex food matrices without a chromatographic separation prior to the analysis. Experiments in the literature demonstrated 22 that taste-active compounds can be identified and quantified below their specific taste thresholds enabling the taste recombination of certain foods solely based on qHNMR quantitative data, offering a fast and sensitive alternative to the conventional approach using ultrahigh-performance tandem mass spectrometry (UHPLC−MS/ MS). With the aim of comparing the conventional approach with the qHNMR approach, published UHPLC−MS/MS methods for the quantitation of general taste compounds 8,19,23 and seafood specific QAC 8 were applied, and a new HILIC-UHPLC−MS/MS MRM method for the quantitation of strong acidic opines was developed.…”

The Sensory-Directed Elucidation of the Key Tastants and Odorants in Sourdough Bread Crumb

“…For data processing, TopSpin 3.6 software (Bruker) was used. Quantitative 1 H NMR spectroscopy was performed by calibrating the spectrometer using external calibration standards of caffeine and tyrosine in D 2 O, by applying the ERETIC II tool (Electronic REference To access In vivo Concentrations) using the PULCON (PULse length based CONcentration determination) methodology and by comparison with the in-house database containing 117 reference taste compounds [ 32 , 36 ]. For the NMR analysis of bread crumb and BCE, quantification was performed under the same conditions as above but with the additional use of the Bruker standard water suppression pulse sequence (1D noesygppr1d) [ 37 ].…”