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Sip volume affects oral release of wine volatiles
... In simulating in-mouth conditions, the release of some volatiles was observed to increase significantly. This phenomenon might be related to the air/water partition coefficient of wine aroma compounds and the presence of saliva (Genovese, Moio, Sacchi, & Piombino, 2015). ...
... To eliminate other excessive interference, several in vitro models are employed with the aim of simulating and predicting the aroma compounds from foods during their consumption (Prinz, Janssen, & De Wijk, 2007;Rabe, Krings, Banavara, & Berger, 2002;Roberts & Acree, 1995). For wine, the retronasal aroma simulator (RAS) is the most widely used model mouth system due to its close simulation of human mouth conditions (Genovese, Moio, Sacchi, & Piombino, 2015;Genovese et al., 2009;Piombino et al., 2019). The RAS was designed to simulate the effects of the oral temperature, saliva or gas flow rate on aroma release (Roberts et al., 1995). ...
... When accounting for differences in the saliva compositions among different populations, the influence of saliva from obese individuals on the release of aroma from wines was investigated using the same methods (Piombino et al., 2014). In addition to the effect of the saliva, the sip volume was identified as a significant parameter that affected the aroma release by simulating wine intake in the RAS device (Genovese et al., 2015). To determine the factors involved in dynamic aroma release, other human mouth models, such as an artificial mouth device, were combined with PTR-MS through nitrogen . ...
During wine consumption, aroma compounds are released from the wine matrix and are transported to the olfactory receptor in vivo, leading to retronasal perception which can affect consumer acceptance. During this process, in addition to the influence of the wine matrix compositions, some physiological factors can significantly influence aroma release leading to altered concentrations of the aroma compounds that reach the receptors. Therefore, this review is focused on the impact of multiple factors, including the physiology and wine matrix, on the aroma released during wine tasting. Moreover, to reflect the pattern of volatiles that reach the olfactory receptors during wine consumption, some analytical approaches have been described for in vitro and in vivo conditions.
... Therefore, the study of the interactions between volatiles and saliva have been approached, but specific papers are still very few. The experiments were carried out on pre-treated (lyophilized, de-aromatized, reconstituted) wines or model hydro-alcoholic solutions added with known volatiles and/or non-volatile wine components (Muñoz-González et al., 2014;Mitropoulou, Hatzidimitriou, & Paraskevopoulou, 2011: Parker et al., 2017 or on whole real wines from Vitis vinifera grapes (Genovese, Moio, Sacchi, & Piombino, 2015;Genovese, Piombino, Gambuti, & Moio, 2009;Piombino et al., 2014). Results agree on some main points: saliva can significantly affect the release of volatiles from wine; this impact depends on the salivary composition (mostly proteins) and physicochemical/biochemical parameters (e.g. total antioxidant capacity) (Muñoz-González, Feron, Brulé, & Canon, 2018;Piombino et al., 2014); even protein at low concentration can significantly affect the release of aroma compounds, for instance salivary enzymes are able to hydrolyze wine aroma precursors; the non-volatile composition of the wine can influence the impact of saliva on the release of odorants; the volatilization of these molecules in the presence of saliva depends on their chemical and physical-chemical characteristics. ...
... Several approaches have been applied for the determination of the aromas present in the headspaces released from a given product, all getting advantages and drawbacks (Wen, Lopez, & Ferreira, 2018, and references therein). In this study, the in mouth processing was mimed as previously described (Genovese et al., 2009;Genovese et al., 2015;Piombino et al., 2014) by a RAS (Retronasal Aroma Simulator) device coupled with SPME (Solid Phase Microextraction) to isolate the volatiles which were identified by GC/MS (Gas-chromatography/Mass Spectrometry) and quantified by GC/FID (Gas-chromatography/Flame Ionization Detector). ...
... The simulated conditions were achieved by using an experimental RAS device equipped with an SPME fiber (Solid Phase Microextraction; Supelco Co., Bellefonte, USA); the design and the method are those previously employed (Genovese et al., 2009, and references therein;Piombino et al., 2014, Genovese et al., 2015. The device consists of a 100 mL mix/reaction glass vessel working at natural pressure and maintained at constant temperature trough an external thermal bath with digital control of the temperature; it is equipped with different valves for gas flowing, SPME device allocation and filling/empting. ...
In this study a Retronasal Aroma Simulator was employed to compare the release of volatiles from two different white wine matrices (TW: table, SW: sweet) with and without the addition of human or artificial saliva to simulate retronasal and orthonasal conditions, respectively. The headspace volatiles were isolated by Solid Phase Microextraction under dynamic conditions and identified and quantified by Gas-Chromatographic analyses. Compared to the orthonasal, the retronasal conditions modified the release of odorants from both wines and the observed trends cannot be ascribed only to dilution consequent to saliva addition. The relative amounts of volatiles belonging to different chemical classes were modified in the presence of saliva with possible sensory implications concerning some fruity (esters), oxidative (furans) and varietal (linalool, vitispirane) odorants. Regression analyses show that the impact of saliva depends on the volatile (concentration and hydrophobicity) and the non-volatile (residual sugars) composition of the wine. The highly significant linear models (TW: R² = 0.988; SW: R² = 0.993) indicate that the release of volatiles is logP octanol/water dependent in both the wines but the slopes change with matrix composition. This suggest that in the presence of human saliva the release of odorants with similar hydrophobicity vary as a linear function of their initial headspace concentration above the wine and is modulated by the composition of the wine matrix. Differences between artificial and human saliva confirmed that the retronasal release of wine odorants is affected by the whole salivary composition and suggest that salivary components different from mucin and α-amylase are involved in the retention of the most hydrophobic volatiles as well as in the metabolization of some aromas.
... Effect of bite size can affect aroma release, likely through different dilution rates, but Genovese et al (2015) also noticed during in vitro experiments that for a same ratio wine/saliva, sip volume could affect aroma release as a function of chemical classes (Genovese, Moio et al. 2015). ...
... Effect of bite size can affect aroma release, likely through different dilution rates, but Genovese et al (2015) also noticed during in vitro experiments that for a same ratio wine/saliva, sip volume could affect aroma release as a function of chemical classes (Genovese, Moio et al. 2015). ...
Le rôle de la salive dans la perception sensorielle est de plus en plus reconnu, notamment par le biais des interactions physico-chimiques pouvant s’établir entre protéines salivaires et constituants alimentaires. Ce travail s’intéresse à la pellicule salivaire, la couche de protéines salivaires ancrées aux cellules épithéliales, et vise à caractériser les interactions pouvant s’établir d’une part entre ces protéines et épithélium oral, et d‘autre part entre ces protéines et les molécules de la flaveur. Pour cela, un modèle in vitro de muqueuse orale a été développé. Une lignée cellulaire stable (TR146/MUC1) a été obtenue par transfection de la lignée cellulaire TR146 de manière à exprimer la mucine membranaire MUC1. Afin de former une pellicule salivaire, les cellules confluentes ont été incubées avec de la salive humaine. La rétention des mucines salivaires MUC5B par les cellules TR146/MUC1 est augmentée par rapport aux TR146, apportant ainsi un argument en faveur de l’implication de MUC1 dans l’ancrage des MUC5B aux cellules épithéliales. Le modèle développé a été appliqué à l’étude des interactions entre la muqueuse orale et les molécules d’arôme et les tanins. L’analyse des coefficients de partage par GC-FID a mis en évidence 1- l’importance de l’hydratation de la muqueuse sur la libération des composés les plus hydrophiles, 2- la capacité des cellules à métaboliser certaines molécules d’arôme, 3- l’absence d’effet de la pellicule sur la libération des molécules d’arôme à l’équilibre. En revanche, l’analyse par PTR-MS a révélé un effet de la muqueuse et de la pellicule sur la cinétique de libération des molécules d’arôme. Les interactions entre les protéines de la pellicule salivaire et les tanins modifient les caractéristiques structurales de la pellicule, en particulier le tapissage des cellules par les MUC5B. Les possibles implications sensorielles, respectivement dans les phénomènes de persistance aromatique et d’astringence, sont discutées.
... Effect of bite size can affect aroma release, likely through different dilution rates, but Genovese, Moio, Sacchi, and Piombino (2015) also noticed during in vitro experiments that for the same ratio wine/saliva, sip volume could affect aroma release as a function of chemical classes (Genovese et al., 2015). ...
... Effect of bite size can affect aroma release, likely through different dilution rates, but Genovese, Moio, Sacchi, and Piombino (2015) also noticed during in vitro experiments that for the same ratio wine/saliva, sip volume could affect aroma release as a function of chemical classes (Genovese et al., 2015). ...
Aroma perception is an important factor driving food acceptance. Volatile organic compounds (VOCs) are released from the food matrix and then reach the receptors located in the nasal cavity, leading to their perception. These steps are closely dependent on the physicochemical properties of the volatile compounds and the food matrix, but also on human physiology. Among the different physiological parameters involved, the literature reports that saliva has various effects on VOCs and therefore appears as a major actor impacting the perception of aroma.
... Sip volume (or bite size) has been reported to have an important impact on oral aroma release of wine (Genovese, Moio, Sacchi, & Piombino, 2015), coffee (Genovese, Caporaso, Civitella, & Sacchi, 2014), and dark chocolate-flavored custard (Ruijschop et al., 2011). Therefore, it is necessary to identify the suitable sip volume of Baijiu for Baijiu oral aroma profiles. ...
The ‘‘after-odor” is essential to the quality and consumer preference of Baijiu. An intra-oral solid-phase microextraction (SPME) combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC-TOFMS) was developed for oral aroma compounds monitoring of Baijiu. The extraction time, sip volume and rinse time were 120 s, 5 mL, and 10 s, respectively. The procedure showed good performances at concentrations of 1.56 μg/L–1500 mg/L for different aroma compounds of Baijiu (most R² > 0.9). Furthermore, the optimized procedure detected 85 aroma compounds with different chemical structures and provided good representations of the light, strong, soy sauce and mix aroma type Baijiu’s oral aroma profiles. Principal component analysis’s (PCA) cumulative interpretation rate was 72.42%. The acceptable performance of this procedure can be combined with dynamic sensory evaluation to improve the quality of the Baijiu aroma.
... It has been observed that wine oxidative notes could be more perceivable during tasting (retronasal) than during sniffing (orthonasal) from the glass (Piombino et al., 2019) and that some VOCs involved in oxidative notes perception were better released under condition simulating wine tasting in small sips (Genovese et al., 2015). This suggests that the perception of oxidative molecular markers can be impacted by factors affecting their portioning and release, such as the non-volatile matrix composition and saliva. ...
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.
... From a physicochemical perspective, special attention has been paid, as of late, to understanding what happens in retronasal simulated and real conditions, reproducing-by model mouths or by real in vivo settings-the aroma release during wine tasting. These approaches are based on the evidence that, together with other in-mouth variables such as wine sip volume [47], salivary components can interact not only with wine polyphenols but also with VOCs, significantly affecting their release [48,49]. ...
Wine polyphenols (PPhs) and volatile organic compounds (VOCs) are responsible for two of the main sensory characteristics in defining the complexity and quality of red wines: astringency and aroma. Wine VOCs’ volatility and solubility are strongly influenced by the matrix composition, including the interactions with PPhs. To date, these interactions have not been deeply studied, although the topic is of great interest in oenology. This article reviews the available knowledge on the main physicochemical and sensory effects of polyphenols on the release and perception of wine aromas in orthonasal and retronasal conditions. It describes the molecular insights and the phenomena that can modify VOCs behavior, according to the different chemical classes. It introduces the possible impact of saliva on aroma release and perception through the modulation of polyphenols–aroma compounds interactions. Limitations and possible gaps to overcome are presented together with updated approaches used to investigate those interactions and their effects, as well as future perspectives on the subject.
... However, the effects of human saliva on these compounds were almost negligible and when observed, a salting-out effect was in general the behaviour detected. The limited effect of saliva on alcohols is also in agreement with the results found in different publications (Buettner 2002a;Friel & Taylor, 2001;Genovese, Moio, Sacchi, & Piombino, 2015;Munoz-Gonzalez, Feron et al., 2014;van Ruth et al., 2001) carried out with diverse techniques, matrix (model solutions vs food) and saliva types (human or artificial salivas). ...
This study investigated the behavior of key aroma compounds in the presence of human saliva (200 μL) from different individuals (n = 3) submitted or not to centrifugation (whole vs clarified saliva). HS-GC results showed that human saliva strongly decreased the release of carbonyl compounds (aldehydes and ketones). This effect was dependent on i) the structure of the aroma compounds and ii) the saliva composition. Whole saliva exerted a higher effect than clarified saliva on aroma compounds. Moreover, this effect was individual-dependent and related to the total protein content and the total antioxidant capacity of saliva. HS-SPME and LLE-GC/MS analyses revealed that metabolism of the compounds by salivary enzymes was involved. This observation indicates that some aroma compounds could be metabolized in the oral cavity in an individual manner, which could have implications for aroma perception (e.g., formation of new metabolites with different odor thresholds and qualities) and/or organisms’ health status (e.g., compound detoxification).
Abstract The preferences of consumers for different flavours and aromas in wine are varied and may be explained by inherent factors such as cultural background, wine education and personal taste of the wine consumer. Wine flavour, as perceived in the mouth, includes aroma compounds released through the retronasal pathway, which are shaped by interactions with saliva. Saliva and wine interactions could provide an explanation as to why wine tasters express different preferences for wine. To test this hypothesis, 13 Western and 13 Chinese experienced wine tasters were recruited. Sensory evaluation was performed in formal surroundings to acquire free description-based and perceived sensory intensity data using the Pivot® Profile and continuous scale assessment, respectively. Participants’ saliva samples were collected before the sensory evaluation and spiked into a wine sample to investigate the impact on the wine’s volatile release using comprehensive two-dimensional gas chromatography–mass spectrometry (GC × GC–MS). Saliva samples were subjected to enzyme activity assays and protein composition profiling by Tandem Mass Tag (TMT) quantitative proteomics. The wine tasters showed differences in wine flavour perception, which was supported by the difference in wine volatile release resulting from the addition of saliva. The two groups of participants did not have significant differences in total salivary protein concentrations or the amounts of esterase and α-amylase. However, statistically significant variations in the concentrations of specific proteins (proline-rich proteins (PRPs) and lipocalin-1 (LCN-1); p
The preferences of consumers for different flavours and aromas in wine are varied and may be explained by inherent factors such as cultural background, wine education and personal taste of the wine consumer. Wine flavour as perceived in the mouth includes aroma compounds released through the retronasal pathway which are shaped by interactions with saliva. Saliva and wine interactions could provide an explanation as to why wine tasters express different preferences for wine. To test this hypothesis, 13 Western and 13 Chinese experienced wine tasters were recruited. Sensory evaluation was performed in formal surroundings to acquire free description-based and perceived sensory intensity data using the Pivot ® Profile and continuous scale assessment, respectively. Participants’ saliva samples were collected before the sensory evaluation and spiked into a wine sample to investigate the impact on the wine volatile release using GC×GC−MS. Saliva samples were subjected to enzyme activity assays and protein composition profiling by Tandem Mass Tag (TMT) quantitative proteomics. The wine tasters showed differences in wine flavour perception, which was supported by the difference in wine volatile release resulting from the addition of saliva. The two groups of participants did not have significant differences in total salivary protein concentrations or the amounts of esterase and α-amylase. However, statistically significant variations in the concentrations of specific proteins (proline-rich proteins (PRPs) and lipocalin-1 (LCN-1); p < 0.01) were found between the two groups. Significant correlations between perceived intensities of wine attributes and concentrations of PRPs and LCN-1 were observed. These results indicate that the composition of proteins in saliva are a factor that influences wine perception and preference. Our results provide a biochemical basis to understanding preference for food based on interactions between aroma compounds and salivary proteins and could be used to suggest foods or beverages to particular cultural groups.
Wine sensory analysis is primarily aimed as determining if one or more wines are statistically distinguishable, to what degree, and for what reasons. Ideally these data can assist grape growers and winemakers in producing better wines, more suited to the tastes of their consumers. To do so, tasters are used as substitute analytical instruments. Thus, much effort is spent training and selection taste panels, since any one individual is likely to be consistently adequate in all situations. Equally, it is critical that tasting be conducted under conditions that exclude as much as possible contextual and psychological influences from biasing perception. Although the tasting conditions appropriate for experimental analysis are divorced from those under which consumers taste wines, the purpose of sensory analysis is not directly related to wine appreciation or commercial ranking. Sensory analysis is aimed at understanding the origins of wine quality—features useful to wine producers.
The release mechanism of odorants in the oral cavity during consumption directly affects sensory attributes, consumers’ preferences, and ultimately purchase intent. Targets was set to monitor in real-time the key odorants released from grilled eel during mastication via an atmospheric pressure chemical ionization mass spectrometry (APCI-MS) connected with a nose interface. The release and perception of odorants during mastication were divided into three distinct phases. Dimethyl sulfide was the main odorant in the first stage. The release and perception of fishy aromas were predominant in the middle and last stages of mastication contributed by trimethylamine, 1-penten-3-ol, and 2-methyl-1-butanol. Chewing behavior experiments suggested that extending the chewing period to >20 s and having a chewing frequency of 2 cycles/s could enhance the aroma delivery of grilled eel and optimize the consumer experience. Consequently, the results explained the relationship between aroma release and the optimal chewing behavior for grilled eel consumption.
Recent evidence suggests that a lower extent of the retronasal aroma release correspond to a higher amount of ad libitum food intake. This has been regarded as one of the bases of behavioral choices towards food consumption in obese people. In this pilot study we investigated the hypothesis that saliva from obese individuals could be responsible for an alteration of the retro-nasal aroma release. We tested this hypothesis in vitro, by comparing the release of volatiles from a liquid food matrix (wine) after its interaction with saliva from 28 obese (O) and 28 normal-weight (N) individuals.
Amplicon sequencing of the 16S rRNA V4 region indicated that Firmicutes and Actinobacteria were more abundant in O, while Proteobacteria and Fusobacteria dominated in N. Streptococcaceae were significantly more abundant in the O subjects and constituted 34% and 19% on average of the saliva microbiota of O and N subjects, respectively. The Total Antioxidant Capacity was higher in O vs N saliva samples. A model mouth system was used to test whether the in-mouth wine aroma release differs after the interaction with O or N saliva. In O samples, a 18% to 60% significant decrease in the mean concentration of wine volatiles was detected as a result of interaction with saliva, compared with N. This suppression was linked to biochemical differences in O and N saliva composition, which include protein content.
Microbiological and biochemical differences were found in O vs N saliva samples. An impaired retronasal aroma release from white wine was detected in vitro and linked to compositional differences between saliva from obese and normal-weight subjects. Additional in vivo investigations on diverse food matrices could contribute to understanding whether a lower olfactory stimulation due to saliva composition can be a co-factor in the development/maintenance of obesity.
Changes in odorant compounds of musts from cv. Pedro Ximenez grapes sun-dried for 0, 2, 4, 6, 8days, as well as dried in chamber after 5days at controlled conditions were studied.
The compounds were analyzed by GC–MS and classified into two groups according to a named production factor (PF), it calculated
as ratio between the average concentration of each compound at the end of the sun-drying and its starting concentration. Acetoin
was the odorant showing the highest content at the end of the sun-drying process. Musts from chamber-dried grapes exhibited
the same aroma terms as those from sun-dried grapes, although in general with higher odor activity values (OAVs), in addition
to chemical odorant term that was only observed in the former. The results suggest an increased extent of raisining in the
controlled conditions of the chamber-drying, which is, reasonably, contributing to improve the raisining process of the grapes
for the production of Pedro Ximenez sweet Sherry wine.
The volatile compounds present in wines are responsible for the quality of the wine aroma. The analysis of these compounds requires different analytical techniques depending on the type of compounds and their concentration. The importance at sensorial level of each compound should be evaluated by using olfactometric techniques and reconstitution and omission studies. In addition, wine aroma is influenced by other factors such as wine matrix, which could affect the compounds' volatility, decreasing or increasing their concentration in the headspace above the wine. Moreover, when a wine is consumed, several oral physiological variables could affect aroma perception. The focus of this review is to outline the most recent advances in wine aroma analysis and the most innovative techniques in trying to elucidate the main factors that influence wine aroma perception during consumption.
During eating, foods are submitted to two main oral processes-chewing, including biting and crushing with teeth, and progressive impregnation by saliva resulting in the formation of a cohesive bolus and swallowing of the bolus. Texture influences the chewing behavior, including mastication and salivation, and in turn, these parameters influence texture perception and bolus formation. During this complex mouth process, flavor compounds are progressively released from the food matrix. This phenomenon is mainly dependent on the food texture, the composition and in-mouth breakdown, and on saliva impregnation and activity, but an individual's anatomical and physiological aspects characteristics should also be taken into account. This article reviews the knowledge and progresses on in-mouth processes leading to food breakdown and flavor release and affecting perception. Relationships between food texture and composition, food breakdown, oral physiology, and flavor release are developed and discussed. This review includes not only the mechanical aspects of oral physiology but also the biological aspects such as the influence of saliva composition, activity, and regulation on flavor perception. In vitro and in silico approaches are also described.
The brain response to a retro-nasally sensed food odour signals the perception of food and it is suggested to be related to satiation. It is hypothesised that consuming food either in multiple small bite sizes or with a longer durations of oral processing may evoke substantial oral processing per gram consumed and an increase in transit time in the oral cavity. This is expected to result in a higher cumulative retro-nasal aroma stimulation, which in turn may lead to increased feelings of satiation and decreased food intake. Using real-time atmospheric pressure chemical ionisation-MS, in vivo retro-nasal aroma release was assessed for twenty-one young, healthy and normal-weight subjects consuming dark chocolate-flavoured custard. Subjects were exposed to both free or fixed bite size (5 and 15 g) and durations of oral processing before swallowing (3 and 9 s) in a cross-over design. For a fixed amount of dark chocolate-flavoured custard, consumption in multiple small bite sizes resulted in a significantly higher cumulative extent of retro-nasal aroma release per gram consumed compared with a smaller amount of large bite sizes. In addition, a longer duration of oral processing tended to result in a higher cumulative extent of retro-nasal aroma release per gram consumed compared with a short duration of oral processing. An interaction effect of bite size and duration of oral processing was not observed. In conclusion, decreasing bite size or increasing duration of oral processing led to a higher cumulative retro-nasal aroma stimulation per gram consumed. Hence, adapting bite size or duration of oral processing indicates that meal termination can be accelerated by increasing the extent of retro-nasal aroma release and, subsequently, the satiation.
It is hypothesized that differences in the extent of retro-nasal aroma release during consumption may be 1 of the reasons that people vary in their satiation characteristics. Using real-time atmospheric pressure chemical ionization mass spectrometry (APcI-MS), in vivo retro-nasal aroma release was determined for 30 subjects consuming 9 different food products, varying in physical structure (i.e., [semi]liquid and solid food products). Additionally, for a subset of the subjects ad libitum food intake was measured. Retro-nasal aroma release intensity and profile morphology appeared to be subject specific and relatively independent of the type of food product subjects consumed. A subject who was observed as having a relatively high retro-nasal aroma release intensity for a (semi)liquid food product also appeared to have a relatively high retro-nasal aroma release intensity for a solid food product. However, for all subjects, there were absolute differences between food products in the extent of retro-nasal aroma release comparing (semi)liquid and solid food products. This implies that the extent of retro-nasal aroma release is a valid physiological feature that characterizes any individual. Interestingly, a negative trend was observed between extent of retro-nasal aroma release and amount of ad libitum food intake (P = 0.07). This may have implications for the regulation of food intake.
Influences of shear rate (surface extension), airflow, in-mouth headspace volume, synthetic saliva and human epithelial cells (modelling mucosa) on the initial dynamic flavour release from liquids were analysed. Simulating physiological mouth parameters, initial dynamic flavour release experiments over a time period of 30 s were carried out using a proven mouth model apparatus. Flavour compounds of different chemical classes were dissolved in water or in aqueous starch hydrolysate in concentrations typically present in food ( micro g/l to mg/l). Forced by increasing shear rates the enlargement of the gas-liquid interface (vortex formation) caused an increased release of flavour molecules. The release of less soluble compounds was reduced by increasing shear forces due to an improved dissolution. Increasing volumetric airflow rates resulted generally in higher release rates and in a change of pattern of release kinetics. Maximum flavour release was found at a ratio of 1:1 for in-mouth headspace and liquid volume. Neither addition of saliva alone nor the combination of saliva and mucosa showed significant influence on in-mouth flavour release from liquids in the model mouth.
Wine is an ancient beverage and has been prized throughout time for its unique and pleasing flavor. Wine flavor arises from a mixture of hundreds of chemical components interacting with our sense organs, producing a neural response that is processed in the brain and resulting in a psychophysical percept that we readily describe as "wine." The chemical components of wine are derived from multiple sources; during fermentation grape flavor components are extracted into the wine and new compounds are formed by numerous chemical and biochemical processes. In this review we discuss the various classes of chemical compounds in grapes and wines and the chemical and biochemical processes that influence their formation and concentrations. The overall aim is to highlight the current state of knowledge in the area of grape and wine aroma chemistry.
The aim of our study was to explain inter-individual differences on in vivo aroma release during cheese consumption by oral physiological parameters.To reach this objective, 34 subjects were recruited. Their salivary flow, oral volume and velum opening were determined. Six cheddar-based melted cheeses with different fat levels and firmness were flavoured with nonan-2-one (NO) and ethyl propanoate (EP). During their consumption (free protocol), in vivo retro nasal aroma release was followed by Atmospheric Pressure Chemical Ionisation-Mass Spectrometry (APCI-MS). Chewing activity was evaluated by electromyography recordings. Bolus saliva content, mouth-coating, and bolus rheology were also determined.Based on the quantity of aroma released before and after swallowing, subjects can be clustered into three groups: the first one (HRG) is characterized by a large quantity of aroma release whatever the aroma compound; the second one (MRG) showed a large release for EP and a lower one for NO; the third group (LRG) was characterized by a low quantity of aroma release whatever the compound.Whatever the group of subjects, fat and firmness effects differed according to the aroma compound. EP release increased with firmness and fat content, whereas NO release was not affected by firmness and decreased when fat content increased. Physiological parameters which better differentiated the three groups of subjects according to their release behaviour were chewing activity, mouth coating and frequency of velum opening.Subjects from HRG were differentiated from LRG subjects by a higher chewing activity, and more frequent velum opening. Subjects from MRG presented a lower mouth coating explaining their lower release of NO, the more hydrophobic compound.This study shows that the total amount of aroma released in the nasal cavity during food consumption depends not only on the characteristics of the product but also on the oral physiology of the subjects and on their food oral processing.
Influences of shear rate (surface extension), airflow, in-mouth headspace volume, synthetic saliva and human epithelial cells (modelling mucosa) on the initial dynamic flavour release from liquids were analysed. Simulating physiological mouth parameters, initial dynamic flavour release experiments over a time period of 30 s were carried out using a proven mouth model apparatus. Flavour compounds of different chemical classes were dissolved in water or in aqueous starch hydrolysate in concentrations typically present in food (µg/l to mg/l). Forced by increasing shear rates the enlargement of the gas–liquid interface (vortex formation) caused an increased release of flavour molecules. The release of less soluble compounds was reduced by increasing shear forces due to an improved dissolution. Increasing volumetric airflow rates resulted generally in higher release rates and in a change of pattern of release kinetics. Maximum flavour release was found at a ratio of 1:1 for in-mouth headspace and liquid volume. Neither addition of saliva alone nor the combination of saliva and mucosa showed significant influence on in-mouth flavour release from liquids in the model mouth.
The aim of this work was to determine the role of saliva on wine aroma release by using static and dynamic headspace conditions. Both methodologies were applied to reconstituted dearomatized white and red wines with different non-volatile wine matrix composition and a synthetic wine (without matrix effect). All the wines had the same ethanol concentration and were spiked with a mixture of forty five aroma compounds covering a wide range of physicochemical characteristics at typical wine concentrations. Two types of saliva (human and artificial) or control samples (water) were added to the wines. The adequacy of the two headspace methodologies for the purposes of the study (repeatability, linear ranges, determination coefficients, etc) was previously determined. After application of different chemometric analysis (ANOVA, LSD, PCA), results showed a significant effect of saliva on aroma release dependent on saliva type (differences between artificial and human) and on wine matrix using static headspace conditions. Red wines were more affected than white and synthetic wines by saliva, specifically human saliva, which provoked a reduction in aroma release for most of the assayed aroma compounds independent of their chemical structure. The application of dynamic headspace conditions using a saliva bioreactor at two different sampling points (t=0 and t=10 min) corresponding with oral (25.5 ºC) and post-oral phases (36 ºC), showed a lesser effect of saliva than matrix composition and a high influence of temperature on aroma release.
The impact of the non-volatile wine matrix composition on the retronasal aroma release of four volatile compounds added to different types of wines has been evaluated. For this purpose, a tailor made retronasal aroma trapping device (RATD) was used to entrap the exhaled breath of six panelists previously trained in a specific consumption procedure. Five wines of different composition (white wine, sparkling white wine, young red wine, aged red wine and a sweet wine), were evaluated. Prior to the evaluation, with the exception of the sweet wine, the wines were adjusted to the same ethanol content and aromatized with a mixture of four target volatile compounds. Aroma release data were submitted to multivariate statistical analysis in order to relate wine chemical composition and aroma release during wine drinking. Results showed inter-individual differences and a clustering of panelists among lower and higher aroma releasers, which was in agreement to the differences in their breathing capacity. A significant influence of the matrix composition in the low aroma releasers group during wine consumption was observed. The consumption of red wines provoked a significantly higher aroma release than the consumption of white and sweet wines. From the chemical composition determined in the wine samples (pH, total acidity, total polyphenols, neutral polysaccharides, residual sugar and nitrogenous compounds), the amount of total polyphenols was better correlated with the observed effect.
A device that simulated retronasal aroma was constructed from a 1 L blender incorporating purge-and-trap, synthetic saliva addition, temperature regulation to 37 degrees C, and blending at shear rates reported to occur during eating. Volatiles were collected on a silica trap, solvent desorbed, and quantitated by GC/FID or GC/MS with high precision (CV < 5%) and sensitivity (micrograms per liter). Increasing the temperature from 23 to 37 degrees C and adding shear increased volatility. The addition of synthetic saliva to a model grape beverage (pH 2.6) increased the pH and the volatility of the bases, 2-acetylpyridine, methyl anthranilate, o-aminoacetophenone, and 2-methoxy-3-methylpyrazine, relative to a model neutral compound, 1,8-cineole. The data were consistent with a sensory test that showed a significant shift in the perception of ''minty'' to ''nutty'' upon the addition of synthetic saliva to a mixture of 1,8-cineole and 2-acetylpyridine in an acid medium. The volatility of eight flavor compounds was investigated in a soybean oil versus water matrix. The volatilities of a-pinene (log P = 3.75), ethyl 2-methylbutyrate, 1,8-cineole, 2-methoxy-3-methylpyrazine, and methyl anthranilate decreased by factors of 8000, 130, 100, 7, and 3 upon oil addition; however, butyric acid did not decrease, and polar maltol (log P = 0.02) actually increased.
The aroma of young white wines altered by oxygen was described by a sensory panel which defined the terms: cooked vegetables, liquor, woody, cider and pungent. Twenty-seven young white wines stored under oxygen for 1 week were analyzed by the sensory panel and were further analyzed by gas chromatography (GC)-Ion trap mass spectrometry (MS) to determine their contents in hexanal, 4-hydroxy-4-methylpentanone, 2-nonanone, 2-buthoxyethanol, t-2-octenal, 1-octen-3-ol, furfural and 5-methylfurfural, benzaldehyde, t-2-nonenal and eugenol. The degrees of aroma degradation induced by oxidation and the acetaldehyde concentration of the wines were measured before and after the oxidation process. The sensory analysis showed that wine aroma degradation is primarily caused by the appearance of a cooked-vegetable odour nuance. The acetaldehyde content of the wines did not vary significantly during the oxidation process, and thereby, cannot be related to the appearance of any of the aroma nuances. Regression data confirm the important role played by eugenol in the woody aromatic nuance, but suggest that important odorants, responsible for the other aromatic nuances, remain unidentified. Some of the compounds analyzed may be used as chemical markers for wine oxidative deterioration. The cooked-vegetable odour nuance can be satisfactorily predicted with quantitative measurements of t-2-nonenal, eugenol, benzaldehyde and furfural.
Wine is a complex alcoholic beverage. The wine matrix or the components that are present in the wine play an important role in the perceived aroma and flavor of the wine. The wine matrix is composed of two fractions, the nonvolatile fraction, which includes ethanol (in liquid phase), polyphenolic compounds, proteins, and carbohydrates, and the volatile fraction, which incorporates flavor and aroma compounds. Interactions among these compounds may arise through various mechanisms, thus affecting the sensory and chemical properties of the wine. The main focus of this review is to highlight recent research on wine component interactions and their effects on perceived aroma in the wine. An overview of the wine impact odorants and their determination using sensory and chemical methods is also provided in this paper.
One hundred and one volatile compounds, reported in literature as powerful odorants of wine, were quantified in a previous study by Gas Chromatography-Selective Ion Monitoring/Mass Spectrometry (GC-SIM/MS) in Primitivo, Aglianico, Merlot and Cabernet Sauvignon red wines. The quantitative data were correlated with the sensory descriptors generated for the six wines by the multivariate analysis. The results showed a good correlation between the odorants detected and the sensory descriptors. Many compounds were correlated to the sensory descriptor they are associated with in the literature. This procedure can be considered a very useful tool to predict how odorants could affect the sensory perception of wine.
The release of volatile organic compounds (VOCs) into the mouth cavity is an integral part of the way flavor is perceived. An in vitro model mouth with an artificial tongue was developed to measure the dynamic release of VOCs from liquid model systems [e.g., aqueous solution, oil, and oil-in-water (O/W) emulsions] under oral conditions. The release of seven selected VOCs was affected by the different polarity and vapor pressure of the compounds and their affinity to the liquid system media. Different tongue pressure patterns were applied to the liquid systems, and the release of VOCs was monitored in real time using proton transfer reaction-mass spectrometry. The release was significantly more intense for longer tongue pressure duration and was influenced by the tongue altering the sample surface area and the distribution of the VOCs. The role of saliva (artificial versus human) and the sample temperature had a significant effect on VOC release. Saliva containing mucin and a higher sample temperature enhanced the release.
Ester concentrations in the headspace influence the aroma character of alcoholic drinks. Activity coefficients for esters showed log-linear decreases as ethanol concentration was increased from 17% (v/v), with rates inversely related to ester acid chain length. At concentrations below 17% (v/v) the activity coefficient remained constant. This could be related to structural changes in ethanol/water mixtures. Below 17% (v/v), ethanol forms a monodispersed aqueous solution. Above 17% (v/v), ethanol molecules cluster to reduce hydrophobic hydration and esters partition into these ethanol-rich clusters, where the lower ester interfacial tension reduces the free energy of mixing and hence the activity coefficient. The increased solubility of the ester reduced the headspace concentration of the esters, and hence total ester content may not be a good indicator of their flavour impact. © 1998 SCI.
ABSTRACTA trained panel of 19 subjects were asked to rate a number of sensory attributes of commercially available vanilla custard desserts. Stimuli were placed in plastic cups and were sampled using 11-mm-diameter straws. In total, 304 samples were weighed before and after sampling and the volume ingested was calculated. The subjects were categorized into two groups on the basis of the mean volume ingested per sample (< and >10.6 mL). There were significant differences in the ratings between the two groups for temperature, creamy, astringent, melting and airy mouthfeels and rough and fatty after-feel. We suggest that in sensory testing, it is important to either control or measure bite size to reduce intersubject variability. Manufacturers and caterers may also be able to modify the perception of their products by providing cues to the appropriate bite size by controlling the size of the spoon or container provided.
Flavour perception is characterised by complex interactions between physicochemical processes (textural properties, aroma release, etc.) and (bio)chemical, physiological and behavioural phenomena. The complexity of ‘peripheral’ processes and their interaction and reciprocal feedback mechanisms is enormous and hitherto not fully understood. In this overview, diverse peripheral factors are discussed with a focus on behavioural responses to sensory stimulation during food consumption and the resulting feedback effects. This review thereby aims at deepening the understanding of a key issue: not only do the chemical structures and concentrations/compositions of food stimuli determine our sensory perception and appreciation of foods, e.g. in terms of flavour acceptance and preference, but specific behavioural and physiological parameters provide additional clues to understand how individuals perceive and respond to stimulations, e.g. acceptance or rejection.
The influence of mastication, saliva composition and saliva volume on aroma release from rehydrated diced bell peppers and French beans was studied in a model mouth system. Released volatile compounds were analysed by gas chromatography combined with sniffing port and flame ionisation detection. Compounds were identified by gas chromatography/mass spectrometry, resulting in more than 40 compounds to be identified in each vegetable. Mastication increased release from bell peppers significantly and increased the number of volatile compounds with detectable odours in sniffing port analysis from six to 10 compounds. Addition of artificial or human saliva resulted in the same aroma profile for bell peppers. The amylase activity of artificial saliva consisting of human or porcine α-amylase was in the same range as amylase activity in human saliva at 37°C. Bacterial α-amylase had lower activity. Human and porcine α-amylase in artificial saliva added to rehydrated French beans did not differ significantly in starch breakdown and affected aroma release similarly. Increase in saliva volume decreased release of aroma compounds from rehydrated French beans significantly. The artificial saliva with porcine or human α-amylase sufficiently simulated human saliva with regard to aroma release. The three parameters mastication, saliva composition and saliva volume were shown to be important factors in aroma release from rehydrated vegetables.
The influence of matrix composition and mastication on the temporal release of seven aroma compounds was studied in a model mouth system. 2-Butanone, diacetyl, ethyl acetate, 3-methyl-1-butanol, hexanal, 2-heptanone and ethyl butyrate were released from water and sunflower oil, with and without mastication, for 15, 30, 60, 120, 240, 480 and 720 s. Aroma compounds were quantified by gas chromatography/mass spectrometry. Volatile compounds were released at significantly different rates. The release of hydrophobic compounds from the oil was decreased, whereas the release of the hydrophilic compound diacetyl was increased in comparison with the water matrix. Interactions were observed between volatile compounds and matrix, as well as between volatile compounds and mastication. Linear release rate constants were related to physico-chemical characteristics, such as molecular weight, boiling points, vapour pressures, octanol–water, gas–water and gas–oil partition coefficients. The octanol–water partition coefficients correlated reasonably well with linear release rate constants for the release from water and oil without mastication, and from water with mastication. The other physico-chemical characteristics correlated poorly with linear release rate constants.
The influence of saliva on aroma release from white and red wines was studied in a model mouth system. Aroma compounds were analysed in the dynamic headspace of wines by solid phase micro extraction/gas chromatography with flame ionization detection. Volatile compounds were identified by solid phase micro extraction/gas chromatography-mass spectrometry, resulting in a total of 43 compounds in white wine and 41 in red wine. The results showed a greater influence of saliva on aroma release in white wine than red wine. In white wine treated with human saliva, esters and fusel alcohols, responsible for fruity and fusel oil odours, were reduced of 32–80%; by contrast, the concentration of 2-phenylethanol and furfural, responsible for rose and toasted almond notes, increased by 27% and by 155%, respectively. In red wine, treated with human saliva, only a few esters decrease, with a reduction of 22–51% due to protein-binding ability of polyphenols that are able to inhibit the activity of the saliva. C-13 norisoprenoids, vitispirane (eucalyptol) and TDN (kerosene), decreased both in white and red wine, showing a comparable variation while, for β-damascenone, the variation was insignificant.
Food oral processing is not only important for the ingestion and digestion of food, but also plays an important role in the perception of texture and flavor. This overall sensory perception is dynamic and occurs during all stages of oral processing. However, the relationships between oral operations and sensory perception are not yet fully understood. This article reviews recent progress and research findings on oral food processing, with a focus on the dynamic character of sensory perception of solid foods. The reviewed studies are discussed in terms of both physiology and food properties, and cover first bite, mastication, and swallowing. Little is known about the dynamics of texture and flavor perception during mastication and the importance on overall perception. Novel approaches use time intensity and temporal dominance techniques, and these will be valuable tools for future research on the dynamics of texture and flavor perception.
A full-factorial design was used to assess the matrix effects of ethanol, glucose, glycerol, catechin, and proline on the volatile partitioning of 20 volatile compounds considered to play a role in wine aroma. Analysis of variance showed that the two-way interactions of ethanol and glucose, ethanol and glycerol, and glycerol and catechin significantly influenced headspace partitioning of volatiles. Experiments were conducted to observe the effect of varied ethanol and glucose concentrations on headspace partitioning of a constant concentration of volatiles. Analysis of variance and linear regression analysis showed that the presence of glucose increased the concentration of volatiles in the headspace, whereas increasing ethanol concentration was negatively correlated with headspace partitioning of volatiles. A subsequent study assessed the effect of diluting white and red wines with water and ethanol. It was again observed that increased ethanol concentration significantly reduced the relative abundance of volatile compounds in the sample headspace. This study investigates some of the complex matrix interactions of the major components of grape and wine that influence volatile compound headspace partitioning. The magnitude of each matrix-volatile interaction was ethanol > glucose > glycerol > catechin, whereas proline showed no apparent interaction. The results clearly identify that increasing ethanol concentrations significantly reduce the headspace concentration of volatile aroma compounds, which may contribute to explaining recent sensory research observations that indicate ethanol can suppress the fruit aroma attributes in wine.
Although hundreds of chemical compounds have been identified in grapes and wines, only a few compounds actually contribute to sensory perception of wine flavor. This critical review focuses on volatile compounds that contribute to wine aroma and provides an overview of recent developments in analytical techniques for volatiles analysis, including methods used to identify the compounds that make the greatest contributions to the overall aroma. Knowledge of volatile composition alone is not enough to completely understand the overall wine aroma, however, due to complex interactions of odorants with each other and with other nonvolatile matrix components. These interactions and their impact on aroma volatility are the focus of much current research and are also reviewed here. Finally, the sequencing of the grapevine and yeast genomes in the past approximately 10 years provides the opportunity for exciting multidisciplinary studies aimed at understanding the influences of multiple genetic and environmental factors on grape and wine flavor biochemistry and metabolism (147 references).
The persistence of volatile compounds in the breath was monitored after their consumption in aqueous solutions. Factors studied were variation in volatile release patterns between panelists, effect of adding hydroxy propyl methyl cellulose (HPMC), and differences among compounds. For any given compound, the extent of volatile persistence was broadly similar for all panelists. Adding HPMC at concentrations in excess of c did not substantially affect persistence. The largest differences in persistence were observed when compounds were compared (>20-fold). The differences were modeled using a quantitative structure property relationship approach, based on the persistence data from 41 compounds. Major components of the model were terms that described the hydrophobicity and vapor pressure of a molecule. The model was validated with a test set, which showed that there was a significant correlation between persistence predicted by the model and the actual values observed.
The volatile content of the effluent from the retronasal aroma simulator (RAS) was compared with that of human breath using mass spectroscopy (MS-Nose). The ratios of volatile compounds from the RAS were closely related to those from the panelists' breath with the correlation coefficients ranging from 0.97 to 0.99 from model food systems. A greater sensitivity using the RAS was achieved because higher concentrations of volatiles in the MS-Nose were produced from the RAS than from the breath. In analyzing the effects on volatility of RAS parameters including airflow rate, temperature, saliva ratio, and blending speed, airflow rate had the greatest effect. The correlation coefficients for the real food systems studied ranged from 0.83 to 0.99. The RAS gives a good approximation of time-averaged flavor release in the mouth as defined by breath-by-breath measurements.
The interactions between saliva components and 20 aroma compounds in water and oil model systems were systematically evaluated as a function of saliva composition and saliva/model system ratio. Air/liquid partition coefficients of dimethyl sulfide, 1-propanol, diacetyl, 2-butanone, ethyl acetate, 1-butanol, 2-pentanol, propyl acetate, 3-methyl-1-butanol, ethyl butyrate, hexanal, butyl acetate, 1-hexanol, 2-heptanone, heptanal, alpha-pinene, 2-octanone, octanal, 2-nonanol, and 2-decanone were determined by static headspace gas chromatography. Chain length of compounds within the homologous series determined the extent of interactions with the model system or saliva. Salts in the artificial saliva hardly interacted with aroma compounds. On the other hand, saliva proteins lowered retention of highly volatile compounds and increased retention of less volatile, hydrophobic compounds. Significant differences in volatility of compounds when artificial saliva or water was added indicated that saliva could not be sufficiently replaced by water. The model system/saliva ratio influenced air/liquid partitioning of the aroma compounds significantly for both model systems. Although saliva composition affected volatility of the aroma compounds, the saliva/model system ratio was of much greater influence.
Partition of fourteen volatile compounds, representing the diverse physicochemical properties of aroma compounds, was measured by static equilibrium headspace in solutions containing the components of artificial saliva, either singly or in mixtures. Comparison of a bovine salivary mucin and pig gastric mucin showed no significant difference in partition behavior of the volatiles, so gastric mucin was used. Mucin viscosity changed with pH, but binding of volatile compounds did not show a marked dependence on pH. All combinations of the salivary components were tested for their effect on partition. Three types of behavior were noted. Partition of some compounds was unaffected by mucin, and with other compounds mucin decreased partition, whereas another group showed a decrease with mucin that was affected by the presence of salivary salts and sugar. When volatiles or sugar were added to a mucin solution, the final headspace concentration depended on the order of addition, indicating some competition for binding. These solute-mucin effects are discussed in relation to mucin structure and behavior in solution.
The application of headspace solid phase microextraction (SPME) for flavor analysis has been studied. Headspace SPME sampling was tested for nine common wine flavor compounds in 10% (v/v) aqueous ethanol: linalool, nerol, geraniol, 3-methyl-1-butanol, hexanol, 2-phenylethanol, ethyl hexanoate, ethyl octanoate, and ethyl decanoate. The chemical groups (monoterpenoids, aliphatic and aromatic alcohols, and esters) showed specific behavior in SPME analysis. SPME sampling parameters were optimized for these components. Relative response factors (RRFs), which establish the relationship between the concentration of the compound in the matrix liquid solution and the GC peak area, were estimated for all compounds. Log(10)(RRF) varied from 0 (3-methyl-1-butanol) to 3 (ethyl decanoate), according to their molecular weight. Quantification by SPME was shown to be highly dependent on the matrix composition; the compounds with higher RRF were the less affected. As a consequence, the data obtained with this methodology should be used taking into consideration these limitations, as shown in the analysis of four monovarietal Bairrada white wines (Arinto, Bical, Cerceal, and Maria Gomes).
A comparison was made between the amounts of volatiles in the headspace above a solution and the breath volatile content (exhaled from the nose or mouth) after consumption of the same solution. The amounts of volatiles in the breath were lower than those in the headspace, with breath exhaled via the mouth containing, on average, 8-fold more volatiles than breath exhaled via the nose. Dilution of the sample by saliva in-mouth did not appear to be a major factor affecting volatile delivery. Instead, the rate of in vivo equilibration (mass transfer) appeared to be the most significant factor, principally affecting volatile delivery from the solution to the gas phase. Thereafter, gas-phase dilution of the volatile as it passed through the upper airway resulted in a further decrease in volatile concentration. The final factor affecting the volatile concentration exhaled from the nose was absorption of volatiles to the nasal epithelia, which was greatest for those compounds with the lowest air/water partition coefficients.
The influence of human whole saliva on odor-active esters and thiols was investigated. Special emphasis was placed on food-relevant concentrations of the odorants. It was found that the amounts of the esters were reduced during incubation with saliva to different extents according to their chemical structures. Considerable degradations were also observed for 2-furfurylthiol, 2-phenylethanethiol, and 3-mercapto-3-methyl-1-butanol, being reduced from approximately 70 to 20% of their initial concentrations within a period of 10 min. Decrease of the odorants did not occur after thermal treatment of the saliva. Generally, the enzymic processes were found to be dependent on the salivary activity of each individual panelist as well as on the odorant's concentrations applied. These investigations were aimed at finding an explanation for the persistence of aftertaste in humans, as it is induced by some odor-active compounds after the consumption of food materials.
Mastication, swallowing, breath flow, and aroma release were measured simultaneously in vivo using electromyography, electroglottography, a turbine air flow meter, and the MS-Nose, respectively. Signals were synchronized either electronically or by aligning the nasal airflow data with the breath by breath release of acetone. Chewing affected nasal airflow, with the flow fluctuations following the mastication pattern. Data analysis suggested that air was pumped out of the mouth into the throat with each chew, and the mean volume was 26 mL. Aroma release was associated with the pulses of air pumped from the mouth with each chew. During swallowing, there was no nasal airflow, but after swallowing, aroma release was evident. The volume of the retronasal route was estimated at 48 mL when swallowing and 72 mL when samples were chewed. The combination of techniques shows the effects of physiological processes on aroma release.
Static equilibrium headspace was diluted with a stream of nitrogen to study the stability of the volatile headspace concentration. The headspace dilution profile of 18 volatile compounds above aqueous and ethanolic solutions was measured in real time using atmospheric pressure chemical ionization-mass spectrometry. Under dynamic conditions the volatiles headspace concentration above water solutions decreased readily upon dilution. The presence of ethanol helped to maintain the volatile headspace concentration when the ethanol solution concentration was above 50 mL/L. This effect was such that under dynamic conditions the absolute volatile concentration above an ethanolic solution was higher than that above an aqueous solution, contrary to results observed in equilibrium studies. The ratio of the headspace concentration of volatiles above ethanolic 120 mL/L and water solutions was correlated to their air/water partition coefficient.
On the basis of a mechanistic model, the overall and liquid mass transfer coefficients of aroma compounds were estimated during aroma release when an inert gas diluted the static headspace over simple ethanol/water solutions (ethanol concentration = 120 mL x L(-1)). Studied for a range of 17 compounds, they were both increased in the ethanol/water solution compared to the water solution, showing a better mass transfer due to the presence of ethanol, additively to partition coefficient variation. Thermal imaging results showed differences in convection of the two systems (water and ethanol/water) arguing for ethanol convection enhancement inside the liquid. The effect of ethanol in the solution on mass transfer coefficients at different temperatures was minor. On the contrary, at different headspace dilution rates, the effect of ethanol in the solution helped to maintain the volatile headspace concentration close to equilibrium concentration, when the headspace was replenished 1-3 times per minute.
Wine tasting: A professional handbook
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Flavors & Fragrances
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