•Interactions between oral mucosa, saliva and aroma compounds were studied in vitro.•Mucosal cells can metabolize several aroma compounds thereby generating new compounds.•Release kinetic patterns ...are different depending on aroma hydrophobicity.•Mucosal pellicle impacts early release, particularly for a less hydrophobic aroma.
The mechanism leading to aroma persistence during eating is not fully described. This study aims at better understanding the role of the oral mucosa in this phenomenon. Release of 14 volatile compounds from different chemical classes was studied after exposure to in vitro models of oral mucosa, at equilibrium by Gas-Chromatography-Flame Ionization Detection (GC-FID) and in dynamic conditions by Proton Transfer Reaction- Mass Spectrometry (PTR-MS). Measurements at equilibrium showed that mucosal hydration reduced the release of only two compounds, pentan-2-one and linalool (p < 0.05), and suggested that cells could metabolize aroma compounds from different chemical families (penta-2,3-dione, trans-2-hexen-1-al, ethyl hexanoate, nonan- and decan-2-one). Dynamic analyses for pentan-2-one and octan-2-one evidenced that the constituents of the mucosal pellicle influenced release kinetics differently depending on molecule hydrophobicity. This work suggests that mucosal cells can metabolize aroma compounds and that non-covalent interactions occur between aroma compounds and oral mucosa depending on aroma chemical structure.
This study investigated the relationship between the ionic binding of sodium and salty perception in protein matrices. Protein type (i.e. gelatin, milk protein and soy protein), protein concentration ...and pH were varied to obtain matrices with distinct compositions and rheological properties. 23Na NMR spectroscopy was used to determine the ratio of sodium ions bound to proteins and the mobility of sodium ions. The results showed that protein type, concentration and pH affected the rheological properties of the protein matrices, the ionic binding of sodium ions and taste intensity. As the protein concentration increased, the mobility of sodium ions decreased and the ratio of bound sodium ions increased. Gelatin matrices displayed the greatest mobility of total sodium ions and the smallest amount of bound sodium. Soy protein had a larger amount of bound sodium than milk protein. Lowering the pH of milk protein matrices tended to decrease the ratio of bound sodium and increase sodium mobility. We suggest that sodium ionic binding is related to the presence of negatively charged groups in proteins. Although changes in matrix composition modified sodium ionic interactions, taste perception was mainly affected by the rheological properties of the protein matrices. As the values of fracture stress or viscosity increased, firmness intensity increased and saltiness intensity decreased. The observed effects of texture on taste could be explained by cross-modal texture-taste interactions and by differences in the oral breakdown behavior of protein matrices.
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•Protein matrices have a fraction of bound sodium ions.•Protein type, concentration and pH affect the ionic binding of sodium ions.•Rheological properties have larger effect on taste perception than sodium ionic binding.
As great differences were observed in the amount of α-amylase in human saliva, there is a need to better understand the effect of this protein alone or in mixture with mucin on aroma compound ...partitioning. We report the respective role of mucin and α-amylase on the air/liquid partition coefficients of two series of 5 methyl-ketones and 5 ethyl-esters. We confirm that mucin affects the release of aroma compounds and, for the first time, we demonstrate the ability of α-amylase to decrease the release of aroma compounds. For both proteins, we report the involvement of hydrophobic effects. Interestingly, no cumulative effect was observed when both proteins were mixed together in solution. We hypothesize that protein–protein interactions occur between the two proteins and decrease the total number of available binding sites for aroma compounds. The effect of human saliva is also investigated and compared to that of artificial salivas. In the presence of human saliva the release of ketones is lower than in water and slightly higher than in the presence of artificial saliva composed of α-amylase and/or mucin. Esters are more affected by the presence of human saliva than ketones. This observation is due to the presence of an esterase activity in saliva, which activity increases with the hydrophobicity of esters. The difference observed in aroma release between artificial and human salivas could be explained by the presence of other salivary proteins in human saliva.
•Retention of aroma compounds is different between human and artificial salivas.•Aroma compounds interact with mucin and α-amylase through hydrophobic effects.•The effect of proteins on aroma retention is different when they are in mixture.•Esters are hydrolyzed into their corresponding acids in the presence of human saliva.
•Model cheese composition affects sodium mobility and free sodium amount.•A lower lipid/protein ratio increased firmness, decreased sodium ions mobility.•A lower lipid/protein ratio decreased in vivo ...sodium release and saltiness.
Reducing salt and lipid levels in foodstuffs without any effect on acceptability is a major challenge, particularly because of their interactions with other ingredients. This study used a multimodal approach to understand the effects of changes to the composition of model cheeses (20/28, 24/24, 28/20 lipid/protein ratios, 0% and 1% added NaCl) on sodium ion mobility (23Na NMR), in-mouth sodium release and flavour perception. An increase in the salt content decreased cheese firmness and perceived hardness, and increased sodium ion mobility, in vivo sodium release and both saltiness and aroma perception. With the same amount of salt, a lower lipid/protein ratio increased the firmness of the cheeses, perceived hardness, and decreased sodium ion mobility, in vivo sodium release, saltiness and aroma perception. These findings suggest on one hand that it could be possible to increase saltiness perception by varying cheese composition, thus inducing differences in sodium ion mobility and in free sodium ion concentration, leading to differences in in-mouth sodium release and saltiness perception, and on the other hand that the reformulation of foods in line with health guidelines needs to take account of both salt content and the lipid/protein ratio.
•A dynamic sensorial evaluation of 6 wines is coupled to dynamic aroma release recording.•Addition of ellagitannin extract impacts the dynamic of sensations of oxidized wine.•Addition of ellagitannin ...extract impacts the length of aroma release in mouth.•Addition of ellagitannin extract preserves fruitiness under oxidative conditions.
Addition of oenological tannins claims to have a positive impact on wine stability, protection from oxidation and likely sensory persistence. However, their role on red wine aroma during oxidation is controversial. The present study aims at investigating the effect of addition of oenological tannins on wine flavour (mainly aroma) before and after air exposure. Temporal Dominance of Sensations, a dynamic sensory evaluation, was coupled with a dynamic chemical measurement (nosespace analysis) using a Proton-Transfer-Reaction Mass-Spectrometer connected to the nasal cavity of 17 assessors. Results showed that the oxidation of a non-oaked Pinot Noir red wine decreases the fruity aroma dominance and increases the maderised and prune one. A contextual decrease of the fruity ethyl decanoate and increase of oxidative Strecker aldehydes are observed. Ellagitannins but not proanthocyanidins preserved perception of fruitiness and prevented increase of maderised notes. Moreover, ellagitannins increase the aroma persistence mainly in the non-oxidized wine.
Proton Transfer Reaction-Time-of-Flight- Mass Spectrometry (PTR-ToF-MS) is an analytical chemistry technique that can be used for measuring the concentration of volatile organic compounds directly in ...the subjects’ noses (nosespace, in vivo analysis) during a tasting and over time. It can be combined with temporal sensory methods such as Temporal Dominance of Sensations (TDS) or Temporal Check All That Apply (TCATA) in order to obtain simultaneous sensory and physico-chemical signals. This paper aims to provide a methodology to analyze in vivo PTR-MS and temporal sensory data and illustrate it on a real dataset. First, relevant pretreatments of PTR-MS data were established, including breathing correction, blank periods removal and standardization. Then, a statistical multiblock analysis was presented: the Regularized Generalized Canonical Correlation Analysis (RGCCA). The versality of the approach was demonstrated, as it can be used to answer most of problematics (exploratory or supervised). Finally, this methodology is illustrated on a dataset of PTR-MS and TDS or TCATA data collected simultaneously. In this study, 16 semi-trained subjects evaluated 3 chocolates in TDS and TCATA on six flavor attributes (Spicy, Cocoa, Woody, Fruity, Roasty and Dry Fruits) with 2 replicates for each sensory method. Results showed that TCATA and TDS gave similar results, but TDS was shown to slightly better preserve the PTR-MS observed product configuration than TCATA. All computing tools developed in this work are freely available.
Proton transfer reaction‐time‐of‐flight‐mass spectrometry (PTR‐ToF‐MS or PTR‐MS) is an analytical chemistry technique that can be used for measuring the concentration of volatile organic compounds ...directly in the subjects' noses (nosespace, in vivo analysis) during a tasting and over time. It can be combined with temporal sensory methods such as temporal dominance of sensations (TDS) or temporal check all that apply (TCATA) in order to obtain simultaneous sensory and physico‐chemical signals. This paper aims to provide a methodology to analyze in vivo PTR‐MS and temporal sensory data and illustrate it on a real dataset. First, relevant pretreatments of PTR‐MS data were established, including breathing correction, blank periods removal, and standardization. Then, a statistical multiblock analysis was presented: the regularized generalized canonical correlation analysis (RGCCA). The versality of the approach was demonstrated, as it can be used to answer most of problematics (exploratory or supervised). Finally, this methodology is illustrated on a dataset of PTR‐MS and TDS or TCATA data collected simultaneously. In this study, 16 semitrained subjects evaluated three chocolates in TDS and TCATA on six flavor attributes (Spicy, Cocoa, Woody, Fruity, Roasty, and Dry Fruits) with two replicates for each sensory method. Results showed that TCATA and TDS gave similar results, but TDS was shown to slightly better preserve the PTR‐MS observed product configuration than TCATA. All computing tools developed in this work are freely available.
Flavor is a mental representation that results from the brain’s integration of at least odor and taste, and fMRI can highlight brain-related areas. However, delivering stimuli during fMRI can be ...challenging especially when administrating liquid stimuli in supine position. It remains unclear how and when odorants are released in the nose and how to improve odorant release.
We used a proton transfer reaction mass spectrometer (PTR-MS) to monitor the in vivo release of odorants via the retronasal pathway during retronasal odor-taste stimulation in a supine position. We tested techniques to improve odorant release, including avoiding or delaying swallowing and velum open training (VOT).
Odorant release was observed during retronasal stimulation, before swallowing, and in a supine position. VOT did not improve odorant release. Odorant release during stimulation had a latency more optimal for fitting with BOLD timing than after swallowing.
Previous in vivo measurements of odorant release under fMRI-like conditions showed that odorant release occurred only after swallowing. On the contrary, a second study found that aroma release could occur before swallowing, but participants were sitting.
Our method shows optimal odorant release during the stimulation phase, meeting the criteria for high-quality brain imaging of flavor processing without swallowing-related motion artifacts. These findings provide an important advancement in understanding the mechanisms underlying flavor processing in the brain.
•Swallowing and velum opening were manipulated to optimize odorant release for fMRI.•Odorants were released during the stimulation, before swallowing in supine position.•Velum opening training does not improve odorant release during stimulation.•Latency of odorant release during stimulation is optimal to fit with BOLD timing.
► Na+ mobility in model cheeses can be investigated by NMR spectroscopy. ► Model cheese structure, rheology and composition affect Na+ mobility. ► Higher protein content and lower NaCl content lead ...to lower mobility of sodium ions.
The mobility and release of sodium ions were assessed in model cheeses with three different lipid/protein ratios, with or without added NaCl. The rheological properties of the cheeses were analysed using uniaxial compression tests. Microstructure was characterised by confocal laser scanning microscopy. 23Na nuclear magnetic resonance (NMR) spectroscopy was used to study the molecular mobility of sodium ions in model cheeses through measurements of the relaxation and creation times. Greater mobility was observed in cheeses containing a lower protein content and with added NaCl. The kinetics of sodium release from the cheese to an aqueous phase was correlated with the mobility of sodium ions. The highest rates of sodium release were observed with a lower protein content and with added NaCl. The water/cheese partition coefficients of sodium increased when NaCl was added or the protein content was higher. The study highlighted the effect of model cheese characteristics on molecular and macroscopic behaviours of sodium.
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