No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Simulation of retronasal aroma of white and red wine in a model mouth system. Investigating the influence of saliva on volatile compound concentrations
Abstract
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.
... 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]. ...
... More-over, saliva can directly impact VOCs dilution, affecting their release to the oral cavity, since the repartition of molecules within the system wine-saliva-air is different compared to the wine-air system [7]. The first works hypothesizing a role played by saliva on PPhs-VOCs interactions during white and red wine tasting have been conducted using model mouth systems, in in vitro conditions, with either human saliva, artificial saliva, or comparing both types [48,63]. In recent years, the development of procedures and methodologies allowing the quantification of aroma release in real in vivo conditions has improved results useful to understand how saliva-polyphenols interactions could impact the release and the perception of wine aroma. ...
... In the specific case of esters, it has been hypothesized that the activity of carboxyl esterase involved in their metabolism might be inhibited in the presence of phenolic compounds, thus leading to a lower hydrolysis of esters in solutions and, consequently, to a higher concentration of molecules that can be released. This hypothesis is supported by results obtained in both in vitro [48] and in vivo [83] conditions. Genovese and co-workers investigated the influence of human and artificial saliva on the release of white and red wine VOCs by SPME/GC-MS analyses using a model mouth system called retronasal aroma simulator (RAS). ...
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.
... By analyzing the change in the amount of aroma released, we can intuitively evaluate the effect of saliva on aroma release. Genovese, Piombino, Gambuti, and Moio (2009) showed an influence of saliva on the aroma release with the analysis of the headspace volatiles in white and red wines; moreover, the release of most aroma compounds was decreased by adding human saliva to a model mouth system. In contrast, according to another study with in vitro static conditions, the release of most hydrophobic compounds from model wines was found to increase in the presence of saliva (artificial saliva) (Mitropoulou, Hatzidimitriou, & Paraskevopoulou, 2011). ...
... 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). ...
... The RAS was designed to simulate the effects of the oral temperature, saliva or gas flow rate on aroma release (Roberts et al., 1995). Genovese and colleagues initially used RAS to study the influence of human saliva on aroma release from wines (Genovese et al., 2009). Recently, RAS was also employed to compare the aroma release from different wines with human or artificial saliva (Piombino et al., 2019). ...
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.
... The scarce studies trying to elucidate the nature of these interactions have been focused on the impact of saliva on wine aroma release by using different methodological approaches (static vs. dynamic headspace), wine matrix compositions (synthetic vs. real wines), tested odorants (mixtures of aroma compounds vs. original wine volatile profile), and salivary composition/treatment (e.g., saliva centrifuged/not centrifuged) [17][18][19]. This makes it difficult to extract conclusions on the nature and significance of aroma-saliva-wine matrix interactions Additionally, recent research using aromatized solutions showed that besides the well-known dilution or salting out effects [20], saliva can act on aroma compounds at very different levels, binding different types of odorants (hydrogen, hydrophobic interactions) [21,22] and/or metabolizing them [23][24][25][26][27][28], which also might give rise to new odorant metabolites [25,27,28]. ...
... Furthermore, both phenolic extracts seemed to have a high inhibitory activity compared to the monomer catechin and the non-flavonoid compound gallic acid, which is in agreement with the higher inhibitory carboxylesterase capacity of flavonoid-type polyphenols [44]. This funding might also explain previous results [17] in which authors observed a higher decrease in ester release in white wines spiked with human saliva compared to red wines (with flavonoid type polyphenols) when using dynamic headspace conditions. ...
... As previously indicated [17], the estimation of the average ratio of liquid food/saliva in the human mouth has been shown to be 5:1 w/v. Blends containing the synthetic wines (hydroalcoholic solution, 10% ethanol, pH 3.5) and each aroma compound were poured in 20 mL headspace vials (Supelco). ...
To determine the impact of oral physiology on the volatility of typical wine aroma compounds, mixtures of a synthetic wine with oral components (centrifuged human saliva (HS), artificial saliva with mucin (AS), and buccal epithelial cells (BC)) were prepared. Each wine type was independently spiked with four relevant wine odorants (guaiacol, β-phenyl ethanol, ethyl hexanoate, and β-ionone). Additionally, the impact of four types of phenolic compounds (gallic acid, catechin, grape seed extract, and a red wine extract) on aroma volatility in the HS, AS, and BC wines was also assessed. Static headspace was measured at equilibrium by solid phase microextraction–GC/MS analysis. Results showed a significant impact of oral components on the volatility of the four tested odorants. Independently of the type of aroma compound, aroma volatility was in general, higher in wines with BC. Moreover, while guaiacol and ethyl hexanoate volatility was significantly lower in wines with HS compared to wines with AS, β-ionone showed the opposite behavior, which might be related to metabolism and retention of mucin, respectively. Phenolic compounds also showed a different effect on aroma volatility depending on the type of compound and wine. Gallic acid had little effect on polar compounds but it enhanced the volatility of the most hydrophobic ones (ethyl hexanoate and β-ionone). In general, flavonoid type polyphenols significantly reduced the volatility of both polar (guaiacol and β-phenyl ethanol) and hydrophobic compounds (β-ionone in HS and BC wines), but through different mechanisms (e.g., π–π interactions and hydrophobic binding for polar and apolar odorants respectively). On the contrary, flavonoids enhanced the volatility of ethyl hexanoate, which might be due to the inhibition exerted on some salivary enzymes (e.g., carboxyl esterase) involved in the metabolism of this odorant molecule.
... A first study demonstrated that aroma release from white wines was more affected by saliva addition than for red wines. This lower effect of saliva on aroma release was attributed to the fact that tannins-salivary proteins complexes inhibited binding of aroma molecules to salivary mucins (Genovese, Piombino et al. 2009). In a more recent study, it was observed in general a reduction of aroma release by saliva addition, but red wines were more affected than white wines. ...
... Ajout salive artificielle ou humaine Plus grande influence de l'ajout de salive sur les vins blancs. ì ou î de la libération selon les arômes Inhibition de l'effet de la salive par les polyphénols : diminution des sites de liaisons protéines/arômes + important dans vins rouges (Genovese, Piombino et al. 2009) ...
... Les complexes polyphénols -protéines salivaires solubles sont aussi susceptibles d'exercer un effet de salting-out sur les composés peu solubles(Mitropoulou, Hatzidimitriou et al. 2011), mais pourraient aussi offrir des régions hydrophobes dans lesquelles ces composés pourraient être retenus(Munoz-Gonzalez, 53 Feron et al. 2014). D'autre part, les complexes formés entre les protéines salivaires et les tanins pourraient diminuer la capacité des protéines salivaires à lier les molécules d'arôme en occupant les sites de liaison aux arômes ou en modifiant la structure des protéines salivaires(Genovese, Piombino et al. 2009). ...
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.
... Un certain nombre d'auteurs ont mis en évidence l'influence des caractéristiques physiologiques orales sur la libération des composés aromatiques (Mestres et al., 2006, Tarrega et al., 2007, Poinot et al., 2009, Genovese et al., 2009). ...
... L'influence des paramètres physiologiques et anatomiques sur la libération des arômes d'une matrice ont parfois été évoqués pour expliquer les fortes différences interindividuelles en terme de libération des arômes (Pionnier et al., 2004b, Mestres et al., 2006 qui pourraient impacter la perception du gras. Parmi ces paramètres, et comme cela a été évoqué dans l'état de l'art, le flux salivaire et le flux respiratoire pourraient directement impacter la libération et la perception des composés présents dans la matrice alimentaire (Boland et al., 2004, Genovese et al., 2009, van Ruth et al., 2000, Buettner et al., 2002, Tréléa et al., 2008, Doyennette et al., 2014. ...
... stimulation alimentaire, la majorité des études visant à comprendre l'impact de la salive sur la libération des composés volatils ont été menées in vitro. En travaillant avec de la salive artificielle(Boland et al., 2004, Genovese et al., 2009) et de la salive réelle(van Ruth et al., 2000, Buettner et al., 2002, Genovese et al., 2009 ces études préliminaires ont montré qu'en fonction des composés aromatiques étudiés et de la matrice alimentaire, la salive peut être impliquée dans la rétention, la dilution et la libération. Cependant, au vu de la variabilité des conditions expérimentales, aucune conclusion n'a pu être établie. ...
Pour réduire la teneur en matière grasse des aliments, et suivre en cela les recommandations du Plan National Nutrition Santé, il est nécessaire de bien comprendre les mécanismes de la perception du gras. Dans ce contexte, ce travail de thèse avait pour objectif de contribuer à la compréhension de la perception du gras au travers de l’étude de la variabilité interindividuelle de la perception du gras et de la recherche de son origine.Pour cela, une approche pluridisciplinaire mêlant physico-chimie de molécules aromatiques à connotation grasse, physiologie orale des sujets, processus en bouche et perception sensorielle au cours de la consommation a été mise en place. Une attention toute particulière a été portée sur la composante olfactive de la perception du gras et en particulier sur la potentielle contribution des métabolites produits dans la cavité nasale de l’Homme à partir de composés volatils odorants. Ce travail montre que la réduction du taux de matière grasse dans un fromage blanc diminue la perception de l’arôme crème, augmente l’amertume et l’astringence et diminue le film gras perçu, confirmant ainsi le caractère multidimensionnel de la perception du gras. Il montre également que la perception du gras est liée à la teneur en lipide du tapissage en bouche ainsi qu’à la composition de la matrice en composés d’arômes.Il met en évidence trois groupes de sujets de sensibilité au gras significativement différents. Ces groupes présentent également des différences pour plusieurs paramètres physiologiques et anatomiques pouvant intervenir sur les sensations tactiles, gustatives et olfactives et donc potentiellement sur la perception du gras.Enfin, ce travail prouve l’existence, dans la muqueuse olfactive de l’Homme, d’enzymes capables de métaboliser les composés odorants en métabolites volatils eux-mêmes odorants susceptibles d’intervenir dans la perception du gras ou de la moduler.
... 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). ...
... Immediately after collection, the human saliva mix (HS) was vortexed in order to guarantee its homogeneity before the splitting into several aliquots which were finally stored at −20°C until the subsequent analyses. Artificial saliva (AS) was prepared as previously described (Genovese et al., 2009, and references therein): Ing, 5.208 NaHCO 3 , 1.369 K 2 HPO 4 ·3H 2 O, 0.877 NaCl, 0.477 KCl, 0.441 CaCl 2 ·2H 2 O, 0.5 NaN 3 , 2.16 mucin (type 1-S from bovine submaxillary glands; Sigma, Milan, Italy) and 200,000 units α-amylase (DFP-treated, Type I-A from porcine pancreas; Sigma, Milan, Italy) in 1 L of distilled water. The saliva was freshly prepared and brought to 37°C prior to experimentation. ...
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.
... L'effet des lipides sur les COVs a été étudié principalement sur des matrices modèle de type émulsions huile dans eau (o/w) ou eau dans huile (w/o), sur des fromages ou desserts laitiers (lait, yaourt, etc.), . Les auteurs La salivation du sujet, de par la composition de la salive et la quantité de salive produite au cours de la dégustation de l'aliment (ratio salive/produit du bol alimentaire) peuvent influencer grandement la libération des COVs (Buettner, 2002a(Buettner, , 2002bDoyennette, Déléris, et al., 2011;Genovese, Piombino, et al., 2009;Van Ruth, Grossmann, et al., 2001;. Les études ainsi menées ont démontré un effet « salting-in » ou « saltingout » de par les protéines salivaires (mucines, α-amylase, etc.), les sels organiques (NaCl, KCl, NaHCO3, etc.) ou le ratio de dilution salive/produit sur la libération des COVs en fonction de leur classe chimique et de leur hydrophobicité. ...
... La physiologie orale pré-dégustation et les cycles de respiration, mastication et déglutition des sujets ainsi que le temps de consommation des produits étant déjà standardisés, l'hypothèse émise est que la présence de salive dans le bol alimentaire pourrait contribuer à la rétention des composés d'arôme au même titre que la texture du produit. En effet, dans la littérature, bon nombre de travaux ont déjà été menés sur l'impact de salive sur la libération des COVs en condition in vitro (Genovese, Piombino, et al., 2009;Mehinagic, Prost, et al., 2004;Muñoz-González, Feron, et al., 2014;Van Ruth, Grossmann, et al., 2001;Van Ruth, Roozen, et al., 1995). Les résultats obtenus montrent que la salive humaine peut avoir un effet saltingin ou bien salting-out sur la libération des COVs en fonction de la nature des composés. ...
... Ces résultats peuvent être toutefois discutés avec ceux de la littérature. L'impact de la salive peut être étudié soit en mode statique (SPME) ou bien dynamique (simulateur de mastication équipé de tubes Tenax ou SPME) avec de la salive humaine ou bien artificielle (Genovese, Piombino, et al., 2009;Mehinagic, Prost, et al., 2004;Muñoz-González, Feron, et al., 2014;Van Ruth, Grossmann, et al., 2001;Van Ruth, Roozen, et al., 1995). Suivant la matrice d'étude, la nature des COVs, les méthodes d'extraction (statique/dynamique) et les protocoles d'extraction (procédure d'équilibre du système, procédure d'extraction, nature de la salive, etc.) utilisés, les résultats obtenus sur l'effet de la salive peuvent être homologues ou bien divergents (effet salting-in ou salting-out ou bien pas d'effet significatif). ...
La perception rétro-nasale (arôme) lors de la mastication en bouche d’un aliment est un phénomène assez complexe. Les compositions physico-chimique et aromatique du produit, son état physique lors de la mastication en bouche, les interactions et réactions mises en jeu dans la cavité buccale sont autant de paramètres qui peuvent influencer cette perception. Dans le cadre de ce travail la mangue sera utilisée comme fruit modèle. Il s’agira de mieux comprendre l’influence du niveau de déstructuration du produit, de la texture ainsi que de la variabilité inter-individuelle d’un panel d’analyse sensorielle sur la perception de l’arôme. La libération des composés volatils lors de la mastication en bouche in vivo du fruit frais, du fruit en forme de purée et du fruit séché sera étudiée par le dispositif RATD(. Le profil aromatique des produits obtenus par la technique SAFE (Solvent assisted flavor evaporation) et les descripteurs aromatiques établis lors de l’analyse sensorielle seront confrontés avec les données RATD.
... These studies have highlighted effects of different nature of saliva on aroma compounds. The retention of aroma compounds by salivary proteins in the presence of artificial (Friel & Taylor, 2001; Pages-Helary, Andriot, Guichard, & Canon, 2014;van Ruth, Grossmann, Geary, & Delahunty, 2001) or human salivas (Genovese, Piombino, Gambuti, & Moio, 2009;Munoz-Gonzalez, Feron et al., 2014;Pages-Helary et al., 2014) is well-documented. Moreover, other mechanism such as the metabolism of aroma compounds (Buettner 2002a(Buettner , 2002bLasekan, 2013) by salivary enzymes, has also been strongly suggested. ...
... However, most of the above-mentioned studies have been carried out with artificial salivas (Friel & Taylor, 2001;Pages-Helary et al., 2014;van Ruth et al., 2001) or pooled salivas submitted or not to a clarification process (Genovese et al., 2009;Munoz-Gonzalez, Feron et al., 2014;Pages-Helary et al., 2014), which could have not completely represented the complexity of human saliva composition as is found in the human mouth (whole saliva). Indeed, human saliva is composed of a wide number of different components, such as electrolytes, proteins and microorganisms, whose profile and proportion is highly individual-dependent (Leake, Pagni, Falquet, Taroni, & Greub, 2016;Neyraud, Palicki, Schwartz, Nicklaus, & Feron, 2012). ...
... It has been previously demonstrated that human saliva impacts the release of aroma compounds (Genovese et al., 2009;Mitropoulou, Hatzidimitriou, & Paraskevopoulou, 2011;Munoz-Gonzalez, Feron et al., 2014;Pages-Helary et al., 2014;Piombino et al., 2014). However, to study the impact of differences in human saliva composition among individuals on aroma compounds, it is necessary to take into account that the collection of suitable volumes of human saliva for experimental purposes is tedious, unpleasant and sometimes (e.g. ...
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).
... Because of this, in the last couple of decades, the study of the retronasal aroma of wine has gained popularity and the number of scientific works dealing with this topic has increased. Most of these studies have been carried out using sensory analysis [9] and using in vitro headspace experiments simulating wine oral conditions [10][11][12][13]. More recently, the use of in vivo approaches to monitor retronasal aroma release in more realistic wine consumption situations have been used, although these works are still scarce [7,[14][15][16][17][18][19][20]. ...
... Both types of approaches can provide us with information about the behavior of wine odorant compounds during real or simulated wine consumption conditions that might better correlate to wine aroma perception than when only using the volatile profile analysis of a wine. In this sense, previous works have attempted to study this behavior by using static or dynamic headspace analysis [10,11,21] to simulate oral conditions. From these studies, it was shown that saliva differently affected the rate of aroma release depending on the type of aroma compound and on the wine matrix composition. ...
The oral release behavior of wine aroma compounds was determined by using an in-mouth headspace sorptive extraction (HSSE) procedure. For this, 32 volunteers rinsed their mouths with a red wine. Aroma release was monitored at three time points (immediately, 60 s, and 120 s) after wine expectoration. Twenty-two aroma compounds belonging to different chemical classes were identified in the mouth. Despite the large inter-individual differences, some interesting trends in oral release behavior were observed depending on the chemical family. In general, esters and linear alcohols showed rapid losses in the mouth over the three sampling times and therefore showed a low oral aroma persistence. On the contrary, terpenes, lactones, and C13 norisoprenoids showed lower variations in oral aroma release over time, thus showing a higher oral aroma persistence. Additionally, and despite their low polarity, furanic acids and guaiacol showed the highest oral aroma persistence. This work represents the first large study regarding in-mouth aroma release behavior after wine tasting, using real wines, and it confirmed that oral release behavior does not only depend on the physicochemical properties of aroma compounds but also on other features, such as the molecular structure and probably, on the characteristics and composition of the oral environment.
... Therefore, the contribution of aroma glycosides to the flavor perception may vary in different food matrix. Genovese et al. (2009) observed less changes in the volatile profile in red wine compared with that of white wine after mixing with saliva. This was probably due to the higher tannins content in red wine that could more efficiently inhibit the activities of enzymes including b-glucosidase (Genovese et al. 2009;Juntheikki and Julkunen-Tiitto 2000). ...
... Genovese et al. (2009) observed less changes in the volatile profile in red wine compared with that of white wine after mixing with saliva. This was probably due to the higher tannins content in red wine that could more efficiently inhibit the activities of enzymes including b-glucosidase (Genovese et al. 2009;Juntheikki and Julkunen-Tiitto 2000). Accordingly, it is plausible to speculate that aroma glycosides have stronger flavor-boosting effects on fruits and fruit products in which concentrations of enzyme inhibitors are lower. ...
Fruit aroma is mainly contributed by free and glycosidically bound aroma compounds, in which glycosidically bound form can be converted into free form during storage and processing, thereby enhancing the overall aroma property. In recent years, the bound aroma precursors have been widely used as flavor additives in the food industry to enhance, balance and recover the flavor of products. This review summarizes the fruit-derived aroma glycosides in different aspects including chemical structures, enzymatic hydrolysis, biosynthesis and occurrence. Aroma glycosides structurally involve an aroma compound (aglycone) and a sugar moiety (glycone). They can be hydrolyzed to release free volatiles by endo- and/or exo-glucosidase, while their biosynthesis refers to glycosylation process using glycosyltransferases (GTs). So far, aroma glycosides have been found and studied in multiple fruits such as grapes, mangoes, lychees and so on. Additionally, their importance in flavor perception, their utilization in food flavor enhancement and other industrial applications are also discussed. Aroma glycosides can enhance flavor perception via hydrolyzation by β-glucosidase in human saliva. Moreover, they are able to impart product flavor by controlling the liberation of active volatiles in industrial applications. This review provides fundamental information for the future investigation on the fruit-derived aroma glycosides.
... The interest in the role of human saliva on the food oral processing is growing in last years (Mosca & Chen, 2017;Muñoz-González, Vandenberghe-Descamps, Feron, Canon, Labouré & Sulmont-Rossé, 2017;Muñoz-González, Feron & Canon, 2018;Ployon, Morzel & Canon, 2017). In several studies, a particular attention is turned to the functions that saliva may play on aroma compounds (Buettner, 2002a;Buettner, 2002b;Genovese, Piombino, Gambuti, & Moio, 2009;Munoz-Gonzalez, Feron, Brule, & Canon, 2018;Munoz-Gonzalez, Feron, Guichard, Rodriguez-Bencomo, Martin-Alvarez, Moreno-Arribas, & Pozo-Bayon, 2014; Pages-Helary, Andriot, Guichard, & Canon, 2014;Piombino, Genovese, Esposito, Moio, Cutolo, Chambery, Severino, Moneta, Smith, Owens, Gilbert, & Ercolini, 2014). These studies, carried out ex vivo, have demonstrated that human saliva and its components can increase or decrease the release of aroma compounds via different mechanisms such as noncovalent interactions, salting-out effects or enzymatic conversion. ...
... However, most of the studies on this topic have employed pooled salivas or individual salivas from a limited number of subjects (Buettner, 2002a;Buettner, 2002b;Genovese et al., 2009;Munoz-Gonzalez et al., 2018;Munoz-Gonzalez et al., 2014;Pages-Helary et al., 2014) that do not represent properly the well-known interindividual variability of human saliva composition in healthy individuals (Leake, Pagni, Falquet, Taroni, & Greub, 2016;Neyraud, Palicki, Schwartz, Nicklaus, & Feron, 2012). Additionally, different pathologies or functional states can provoke biochemical and microbiological changes in salivary parameters raising the This article is protected by copyright. ...
The aim of this work was to study the effects of interindividual variability of human elderly saliva on aroma release and metabolisation by ex vivo approaches. Thirty individuals suffering or not from hyposalivation were selected from a panel formed by 110 elderly people (aged >65 years old) that were matched by age and sex. Then, their stimulated saliva samples were independently incubated in presence of three aroma compounds (ethyl hexanoate, octanal, 2‐nonanone) to perform headspace‐gas chromatography (HS‐GC) and liquid/liquid extraction‐gas chromatography mass spectrometry (LLE‐GC/MS) analyses. These assays revealed that the extent of saliva effect on the release and metabolisation of aroma compounds was highly dependent on the chemical family of the compounds (octanal>ethyl hexanoate>2‐nonanone). Moreover, salivas from the hyposalivator (HPS) group exerted a significant lower release and/or higher metabolisation than those of the control group for the three assayed compounds. Regarding the biochemical characterization of the saliva samples, no significant differences were found in the total protein content between the two groups. This does not preclude the involvement of specific proteins on the observed results that need to be clarified in further experiments. Saliva from the HPS group presented a significantly higher total antioxidant capacity than that of the control group, which suggests that this parameter could be related to the metabolisation of aroma compounds by saliva. Such effects might alter aroma perception in individuals suffering from hyposalivation.
This article is protected by copyright. All rights reserved.
... competence phenomenon). Besides of this, different works in the literature have described interactions among aroma molecules and wine matrix components using different -in vitro approaches (Dufour & Bayonove, 1999;Genovese, Piombino, Gambuti, & Moio, 2009;Jung & Ebeler, 2003;Mitropoulou, Hatzidimitriou, & Paraskevopoulou, 2011;Robinson, Ebeler, Heymann, & Trengove, 2009;Rodríguez-Bencomo et al., 2011;Villamor, Evans, Mattinson, & Ross, 2013). Therefore, it is likely that these interactions might also happen in oral conditions modifying the rate of retention/release of aroma compounds from the oral mucosa and ultimately wine aroma persistence. ...
... Moreover, this study proved a higher effect of human saliva compared to artificial saliva in the case of red wines, which was attributable to the different phenolic composition of red wines compared to white wines. Other studies using dynamic -in vitro conditions confirmed the different impact of human saliva on wine aroma volatility in red versus white wines (Genovese et al., 2009). Results of this work, confirmed the different effect of different types of polyphenol compounds on aroma release, which might explain the differences found in these previous studies. ...
The aim of this study has been to investigate if wine matrix composition might influence the interaction between odorants and oral mucosa in the oral cavity during a “wine intake-like” situation. Aroma released after exposing the oral cavity of three individuals to different wines (n = 12) previously spiked with six target aromas was followed by an -in vivo intra-oral SPME approach. Results showed a significant effect of wine matrix composition on the intra-oral aroma release of certain odorants. Among the wine matrix parameters, phenolic compounds showed the largest impact. This effect was dependent on their chemical structure. Some phenolic acids (e.g. hippuric, caffeic) were associated to an increase in the intra-oral release of certain odorants (e.g. linalool, β-ionone), while flavonoids showed the opposite effect, decreasing the intra-oral release of aliphatic esters (ethyl hexanoate). This work shows for the first time, the impact of wine composition on oral-mucosa interactions under physiological conditions.
... Regarding aroma perception, namely the retro-nasal pathway, volatile molecules, before being detected by olfactory receptors, are influenced by factors such as body temperature and saliva pH, allowing the identification of different and equally important aromas [20,21]. When volatiles are released from food into the saliva phase, chemical and biochemical reactions occur, which could affect the volatile concentration and retro-nasal aroma perception [22]. ...
The introduction of a drink in the mouth and the action of saliva and enzymes cause the perception of basic tastes and some aromas perceived in a retro-nasal way. Thus, this study aimed to evaluate the influence of the type of alcoholic beverage (beer, wine, and brandy) on lingual lipase and α-amylase activity and in-mouth pH. It was possible to see that the pH values (drink and saliva) differed significantly from the pH values of the initial drinks. Moreover, the α-amylase activity was significantly higher when the panel members tasted a colorless brandy, namely Grappa. Red wine and wood-aged brandy also induced greater α-amylase activity than white wine and blonde beer. Additionally, tawny port wine induced greater α-amylase activity than red wine. The flavor characteristics of red wines due to skin maceration and the contact of the brandy with the wood can cause a synergistic effect between beverages considered "tastier" and the activity of human α-amylase. We can conclude that saliva-beverage chemical interactions may depend on the saliva composition but also on the chemical composition of the beverage, namely its constitution in acids, alcohol concentration, and tannin content. This work is an important contribution to the e-flavor project, the development of a sensor system capable of mimicking the human perception of flavor. Furthermore, a better understanding of saliva-drink interactions allow us to comprehend which and how salivary parameters can contribute to taste and flavor perception.
... Buettner demonstrated the disappearance of ethyl butanoate, ethyl hexanoate, and ethyl octanoate after incubation with fresh saliva and the correlated production of the corresponding carboxylic acids (Buettner, 2002b). Additionally, it was shown that the concentration of total esters in wine headspace decreased in the presence of human saliva, suggesting that saliva contains esterases active toward flavor esters (Genovese et al., 2009). This effect was determined to be more pronounced with white wine than with red wine; thus, the authors suggested that the presence of tannins in red wine, which also trigger the trigeminal astringency sensation , can explain this difference due to their ability to interact with (Canon et al., 2010) and aggregate proteins (Canon et al., 2013), and inhibit enzymatic activity. ...
The perception of flavor is a complex phenomenon, resulting from the activation of sensory receptors sensitive to stimuli of different nature, including chemical and physical stimuli. The detection of chemicals relies on the activation of chemoreceptors. Aroma compounds bind to olfactory chemoreceptors, sapid molecules to a taste chemoreceptor, and trigeminal molecules to transient receptor potential channels. These same channels can be activated by temperature. However, food is never in direct contact with the chemoreceptors; as a result, flavor compounds have to be released from food before being transported by saliva or air. During this last step, different perireceptor mechanisms can also take place, especially in the mouth during food consumption. These include, for example, partitioning between different phases (food matrix, saliva, air of the buccal cavity), non-covalent interactions but also enzymatic biotransformation. Many studies have reported the influence of the intrinsic physicochemical properties of flavor molecules such as hydrophobicity or volatility to describe the partitioning mechanisms. However, linear model based on these properties failed to explain the behavior of compounds of different nature in presence of saliva. Recent findings suggest that salivary proteins and their properties such as enzymatic conversion could play a role, beside physicochemical mechanisms. The oral enzymatic biotransformation of flavor molecules in the mouth impacts both the quality and the quantity of flavor molecules. Indeed, the concentration of the metabolized molecules decreases while the resulting metabolites can activate other chemoreceptors. According to some pioneer studies, this oral metabolism has an impact on the perception of flavors. Interestingly, the entailed enzymatic activities are subject to inter-individual variations and could be an important factor to be taken into account when investigating the origin of food preferences. In this chapter, we review the current state-of-the-art on the mechanisms of biotransformation of flavor molecules in the mouth and their importance for the sensory perception of food. Although few studies have been carried out on this emerging topic, in-mouth flavor metabolism should be taken into account in the future when designing food products, as it might explain interindividual variability of perception.
... Different studies have pointed out that wine polyphenols could form binary/ternary complexes with saliva proteins from the free circulating saliva or from the mucosa pellicle, being able to encapsulate aroma molecules. 32,44,45 These complexes could form reservoirs of aroma molecules in the mouth, which might decrease the immediate aroma release, 46,47 but can contribute to the long lasting aroma perception (aroma persistence), when they are progressively released. 48,49 In fact, the adsorption of polyphenols to salivary proteins 24 or to oral epithelial cells 50 has been shown, proving that they can persist several hours after the intake of polyphenol-rich beverages (coffee and chocolate beverages). ...
The dynamic changes in saliva flow and composition (pH, total protein capacity (TPC), total polyphenol index (TPI) and saliva antioxidant activity (SAOX)) after the exposure of the oral cavity to aromatized wine matrices with different chemical compositions (dealcoholized, alcoholized, and synthetic wines) have been investigated. For this, stimulated saliva from ten volunteers were collected five days per week (from Monday to Friday) during three non-consecutive weeks, before (basal saliva) and after the oral intervention with the wines (5 and 15 minutes later) (n = 450). In order to know the relationship between the changes induced in salivary composition and the amount of aroma retained in the oral cavity, the expectorated wines were also collected (n = 150). Results showed differences in saliva composition (pH, TPI and SAOX) depending on the wine matrix that were only significant in the first five minutes after the oral exposure to the wines. The wines with ethanol produced significantly lower in-mouth aroma retention, while salivary TPI and, to a minor extent, SAOX, were positively related to the aroma retained. These results prove that not only wine aroma composition, but also the physiological changes in saliva induced by the non-volatile chemical composition of the wine play an important role in wine odorant compounds, and likely, in aroma perception.
... The partition coefficients of esters and alcohols were decreased, whereas ketones and alcohols were characterized by the increased partition coefficients in the presence of saliva [166]. The inhibition of the volatility of aromatic compounds by saliva has been shown in the presence of artificial [187][188][189] or volunteers' human stimulated saliva [190,191]. The interaction of salivary proteins with aromatic compounds can explain the decrease in the volatility of some aromatic compounds [192,193]. ...
Saliva plays multifunctional roles in oral cavity. Even though its importance for the maintenance of oral health has long been established, the role of saliva in food perception has attracted increasing attention in recent years. We encourage researchers to discover the peculiarity of this biological fluid and aim to combine the data concerning all aspects of the saliva influence on the sensory perception of food. This review presents saliva as a unique material, which modulates food perception due to constant presence of saliva in the mouth and thanks to its composition. Therefore, we highlight the salivary components that contribute to these effects. Moreover, this review is an attempt to structure the effects of saliva on perception of different food categories, where the mechanisms of salivary impact in perception of liquid, semi-solid, and solid foods are revealed. Finally, we emphasize that the large inter-individual variability in salivary composition and secretion appear to contribute to the fact that everyone experiences food in their own way. Therefore, the design of the sensory studies should consider the properties of volunteers’ saliva and also carefully monitor the experimental conditions that affect salivary composition and flow rate.
... In the case of esters, Buettner demonstrated the disappearance of ethyl butanoate, ethyl hexanoate, and ethyl octanoate after incubation with fresh saliva (Buettner, 2002b) and the correlated production of the corresponding carboxylic acids (Pages-Helary et al., 2014). In a study on the impact of saliva on wine aroma molecules, it was shown that the concentration of total esters in wine headspace decreased in the presence of human saliva (Genovese et al., 2009). This effect was determined to be more pronounced with white wine than with red wine; thus, the authors suggested that the presence of tannins in red wine can explain this difference due to their ability to inhibit enzymatic activity. ...
The oral cavity is an entry path into the body, enabling the intake of nutrients but also leading to the ingestion of harmful substances. Thus, saliva and oral tissues contain enzyme systems that enable the early neutralization of xenobi-otics as soon as they enter the body. Based on recently published oral proteomic data from several research groups, this review identifies and compiles the primary detoxification enzymes (also known as xenobiotic-metabolizing enzymes) present in saliva and the oral epithelium. The functions and the metabolic activity of these enzymes are presented. Then, the activity of these enzymes in saliva, which is an extracellular fluid, is discussed with regard to the salivary parameters. The next part of the review presents research evidencing oral metaboliza-tion of aroma compounds and the putative involved enzymes. The last part discusses the potential role of these enzymatic reactions on the perception of aroma compounds in light of recent pieces of evidence of in vivo oral metabolization of aroma compounds affecting their release in mouth and their perception. Thus, this review highlights different enzymes appearing as relevant to explain aroma metabolism in the oral cavity. It also points out that further works are needed to unravel the effect of the oral enzymatic detoxification system on the perception of food flavor in the context of the consumption of complex food matrices, while considering the impact of food oral processing. Thus, it constitutes a basis to explore these biochemical mechanisms and their impact on flavor perception.
... Furthermore, its olfactory perception can be modified by wine matrix constituents, including nonvolatile compounds (e.g., acids, polysaccharides, proteins, glucose or fructose, and polyphenols) and ethanol as they can retain volatile compounds and influence their volatility (Dufour & Bayonove, 1999;Robinson et al., 2009;Sáenz-Navajas et al., 2010;Villamor & Ross, 2013). During retronasal perception, retention can be related to the interaction of volatile compounds with nonvolatile wine compounds (Pittari et al., 2021) and saliva (Genovese et al., 2009;Muñoz-González et al., 2014). Another major dimension of the perception of wine aroma relies on the perceptual interactions that occur at the brain level due to the complex stimuli trigger by the mixtures of volatile compounds (Thomas-Danguin et al., 2014). ...
Wine aroma, which stems from complex perceptual and cognitive processes, is initially driven by a multitude of naturally occurring volatile constituents. Its interpretation depends on the characterization of relevant volatile constituents. With large numbers of volatile constituents already identified, the search for unknown volatiles in wine has become increasingly challenging. However, the opportunities to discover unknown volatile compounds contributing to the wine volatilome are still of great interest, as demonstrated by the recent identification of highly odorous trace (µg/L) to ultra‐trace (ng/L) volatile compounds in wine. This review provides an overview of both existing strategies and future directions on identifying unknown volatile constituents in wine. Chemical identification, including sample extraction, fractionation, gas chromatography, olfactometry, and mass spectrometry, is comprehensively covered. In addition, this review also focuses on aspects related to sensory‐guided wine selection, authentic reference standards, artifacts and interferences, and the evaluation of the sensory significance of discovered wine volatiles. Powerful key volatile odorants present at ultra‐trace levels, for which these analytical approaches have been successfully applied, are discussed. Research areas where novel wine volatiles are likely to be identified are pointed out. The importance of perceptual interaction phenomena is emphasized. Finally, future avenues for the exploration of yet unknown wine volatiles by coupling analytical approaches and sensory evaluation are suggested.
... A moderate amount of n-propanol forms a refreshing and mellow taste in baijiu. However, if its content is too high, the baijiu will have an ethereal odor and bitter taste, which makes it unpleasant to drink and can even cause poisoning [5][6][7][8]. It is very important to control the content of n-propanol in the process of Chinese baijiu brewing to realize high-quality liquor brewing. ...
N-propanol is a vital flavor compound of Chinese baijiu, and the proper n-propanol contents contribute to the rich flavor of Chinese baijiu. However, the excessive content of n-propanol in liquor will reduce the drinking comfort. Based on the Box–Behnken design principle, the response surface test was used to optimize the factors affecting the production of n-propanol in a simulated liquid state fermentation of Chinese baijiu, and the best combination of factors to reduce n-propanol content was determined. Results showed that the content ratio of additional glucose to threonine and temperature had a significant effect on the production of n-propanol (P = 0.0009 < 0.01 and P = 0.0389 < 0.05, respectively). The best combination of fermentation parameters obtained was: the ratio of additional glucose to threonine content was 6:4, the temperature was 32 °C, and the initial pH was 4.40. Under these conditions, the production of n-propanol was 53.84 ± 0.12 mg/L, which was close to the theoretical value. Thus, the fermentation parameter model obtained through response surface optimization is reliable and can provide technical guidance for regulating the production of n-propanol and realizing high-quality baijiu brewing.
... Several publications have stressed the fact that saliva may partly influence the sensory perception of a food [118,119]. Salivary amylolytic activity is widely known, but also proteolytic and lipolytic activity has been reported for the saliva [120,121]. ...
Virgin olive oil (VOO) has unique chemical characteristics among all other vegetable oils which are of paramount importance for human health. VOO constituents are also responsible of its peculiar flavor, a complex sensation due to a combination of aroma, taste, texture, and mouthfeel or trigeminal sensations. VOO flavor depends primarily on the concentration and nature of volatile and phenolic compounds present in olive oil which can change dramatically depending on agronomical and technological factors. Another aspect that can change the flavor perception is linked to the oral process during olive oil tasting. In fact, in this case, some human physiological and matrix effects modulate the flavor release in the mouth. The present review aims to give an overview on VOO flavor, with particular emphasis on the mechanisms affecting its production and release during a tasting.
... They then interact with the oral cavity surfaces and/or are released via the airflow to the olfactory receptors (Muñoz-González, . Different ex vivo studies have shown that human saliva and its components can increase or decrease the release of aroma compounds through different physicochemical mechanisms such as non-covalent interactions, "salting-out" effects or enzymatic conversion (Buettner, 2002a(Buettner, , 2002bGenovese, Piombino, Gambuti, & Moio, 2009;Muñoz-González, Feron, Brulé, & Canon, 2018;Pagès-Hélary, Andriot, Guichard, & Canon, 2014;Piombino et al., 2014). More recently, the relationship between saliva composition and wine aroma perception has been proven . ...
Salivary flow and composition have been related to the dynamics of retronasal aroma release during wine consumption. However, whether differences in saliva composition among age groups are related to wine aroma perception remains unexplored. Therefore, the aim of this work has been to determine the relationship between salivary parameters and the dynamics of wine retronasal aroma perception in two groups of individuals of different age (young and senior adults). To do so, 22 individuals, 11 from the young group (18-35 years old) and another 11 from the senior group (>55 y.o.) were recruited for this study. The retronasal aroma intensity of two specific aroma attributes (smoked and black pepper) of a red wine was rated by using Time-Intensity (TI) methodology. Saliva was previously collected from each individual. Salivary flow and composition (pH, total protein content, protease and α-amylase activities) were determined in order to characterise the two groups of panellists. Results showed significant differences among age groups (young and seniors) in the TI parameters extracted from the dynamics curves of retronasal aroma perception of both attributes. Thus, smoky and black pepper notes were more intensely rated and for longer times by the senior group than by the younger group. Salivary parameters were also significantly different in both age groups. A significant positive correlation between the salivary total protein content and the maximum intensity (Imax) perceived, and a significant negative correlation between the salivary flow and most TI parameters (Imax, area under the curve and duration time of the perceived stimuli) were found for both aroma attributes.
... Numerous studies have demonstrated different mechanisms of saliva inuencing volatile compounds such as, dilution, retention by salivary proteins, salting-out effects or enzymatic conversion. [21][22][23][24][25][26][27] In this way, the capacity of salivary enzymes to metabolize certain groups of aroma compounds such as thiols, ketones, aldehydes and esters have been previously reported. 17,20,21,26,28 In the specic case of esters, synthesis or hydrolysis processes catalysed by enzymes could be particularly likely, since it is well known that human saliva presents esterase activity. ...
Salivary esterase enzymes have been related to the in vitro hydrolysis of carboxylic esters associated with fruity and pleasant aroma nuances in many types of wine. However, very little is known about human total salivary esterase activity (TSEA) under physiological conditions. The purpose of this study is to gain understanding of TSEA and its relevance under wine consumption conditions. To do this, a methodology for TSEA measurement was optimised and applied to examine inter-individual differences (n = 10). Furthermore, TSEA was correlated with other salivary parameters (flow, pH, total protein content). The effect of the oral exposure to different types of wine-like solutions with different composition (ethanol, phenolic and aroma compounds) on TSEA was also assessed. Results showed large inter-individual differences, up to 86%, on TSEA values. Additionally, TSEA was positively correlated with the total salivary protein content (TPC) and negatively correlated with salivary pH and flow. After the oral exposure to wine-like solutions, the combined presence of ethanol, carboxylic esters and phenolic compounds produced the highest TSEA value. Results from this work prove that human salivary esterase is active during wine consumption, and adds support to the involvement of this enzymatic activity on wine aroma perception during wine intake, which will require future studies.
... [21], c [30], d [31], e [32], f [33], g [29], h [34]. [35], c [30], d [36], e [37], f [38], g [21], h [39], i [29], j [33], k [22]. ...
Volatile organic compounds (VOCs) play a crucial role in cider quality. Many variables involved in the fermentation process contribute to cider fragrance, but their relative impact on the finished odor remains ambiguous, because there is little consensus on the most efficient method for cider volatile analysis. Herein, we have optimized and applied a headspace solid phase microextraction gas chromatography–mass spectrometry (HS-SPME GC-MS) method for the chemical analysis of cider VOCs. We determined that the 30 min exposure of a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) solid phase microextraction (SPME) fiber at 40 °C yielded detection of the widest variety of VOCs at an extraction efficiency >49% higher than comparable fibers. As a proof-of-concept experiment, we utilized this method to profile cider aroma development throughout the fermentation process for the first time. The results yielded a very practical outcome for cider makers: a pre-screening method for determining cider quality through the detection of off-flavors early in the fermentation process. The aroma profile was found to be well established 72 h after fermentation commenced, with major esters varying by 18.6% ± 4.1% thereafter and higher alcohols varying by just 12.3% ± 2.6%. Lastly, we analyzed four mature ciders that were identically prepared, save for the yeast strain. Twenty-seven key VOCs were identified, off-flavors (4-ethylphenol and 4-ethyl-2-methoxyphenol) were detected, and odorants were quantified at desirable concentrations when compared to perception thresholds. VOCs varied considerably following fermentation with four novel strains of S. cerevisiae, evidencing the central importance of yeast strain to the finished cider aroma.
... Ce phénomène nous interroge ainsi sur la part gustative dans la perception de ces composés par rapport à la part olfactive. La salive peut aussi favoriser la libération d'arômes par un Innovations Agronomiques 10 (2010), 69-80 75 effet dit de "salting out" déjà montré sur d'autres matrices alimentaires (Genovese et al, 2008). Pour les produits riches en matière grasse, cet effet a été supposé dans le cas de matrices de types fromage où le taux d'incorporation de salive est légèrement dépendant du taux de matière grasse . ...
Colloque du 9 novembre 2010 : Les lipides: enjeux sensoriels et nutritionels
... The antimicrobial activity of nonfermented tea is higher than that of semi-fermented or fermented tea. Moreover, the highest antimicrobial activity occurs in samples with the highest total polyphenol concentration and antioxidant activity [26][27][28][29]. The presence of tiny amounts of fluoride improves the health of gums and teeth by destroying bacteria [30]. ...
... Interestingly, human saliva carries enzymes that act breaking bonds with sugars, for instance salivary amylase [23], and as soon as wine mixes with saliva, such chemical reactions take place and the newly formed beverage's gaseous phase can follow the so called Retropharyngeal Path and be sensed as a smell [24]. Saliva causes other variations on wine molecules [25] due to other enzymes and proteins, in fact the basic acid reaction that occurs when wine pH from 3 to 4 [26] mixes to saliva fairly neutral pH [27] causes a shift in chemical form of many molecules potentially bringing them from un-aromatic to aromatic or the other way around. This could be the reason that explains why a wine's flavor perception is different after swallowing if compared with the olfactory exam one. ...
Background: Recently, one of the most debated problems within the wine tasters community, is whether personal biological variability can affect the wine flavors sensing or not. In other words, can wine aroma perception be considered as an absolute truth?
Methods: The present paper demonstrates that, relying on proven data, that the answer is no. Few research about this topic has been published, but data clearly show evident biochemical intravariabilities, mostly based on oral bacteria enzymes secretion.
Results: Individual variability in receptors expression dramatically affect this process, but the combination between both oral bacteria-derived and salivary enzymes seems to be the pivotal factor able to dissociate aromatic compounds from sugars and allow them to pass from liquid to gaseous phase, so that, following the Retropharyngeal Path, they can be sensed by olfactory neurons placed at tectory level, that can however express receptors in a variable and genetically-based manner.
Conclusion: The aim of the present work is that of provide tools to rethink wine tasting, constructing an evidence-based perspective in the broad world of wine.
... Artificial saliva was composed of recommended ingredients (Genovese, Piombino, Gambuti, & Moio, 2009): 5.2 g NaHCO 3 , 1.37 g K 2 HPO 4 · 3H 2 O, 0.90 g NaCl, 0.5 g KCl, 0.44 g CaCl 2 · 2H 2 O, 0.5 g NaN 3 , 2.2 g mucin (type 1-S from bovine submaxillary glands; Sigma, Milan, Italy) and ...
In this study, atmospheric pressure chemical ionisation-mass spectrometry (APCI-MS) was successfully applied to understand the effect of phenolic compounds on the release of olive oil aroma compounds. Eight aroma compounds were monitored under in-vivo and in-vitro dynamic conditions in olive oil with and without the addition of virgin olive oil (VOO) biophenols. Three model olive oils (MOOs) were set up with identical volatile compounds concentrations using a refined olive oil (ROO). Phenolics were extracted from VOOs and were added to two MOOs in order to obtain two different concentrations of phenolic compounds (P+ = 354 mg kg−1; P++ = 593 mg kg−1). Another MOO was without VOO biophenols (P−). Phenolic compounds impacted both the intensity and time of aroma release. In the in-vivo study, 1-penten-3-one, trans-2-hexenal and esters had lower release in the presence of higher levels of biophenols after swallowing. In contrast, linalool and 1-hexanol had a greater release. The more hydrophobic compounds had a longer persistence in the breath than the hydrophilic compounds. VOO phenolics-proline-rich proteins complexes could explain the binding of aroma compounds and consequently their decrease during analysis and during organoleptic assessment of olive oil.
... Several studies have reported a difference between retronasal and orthonasal perception of the same odorant molecule, indicating an influence of the oral physiology on aroma perception (Burdach et al. 1984, Kuo et al. 1993, Linforth et al. 2002, Voirol and Daget 1986. Among the different factors influencing the release of volatile compounds, the impacts of saliva (Genovese et al. 2009, Munoz-Gonzalez et al. 2014) and of oral volume (Mishellany-Dutour et al. 2012) were evidenced. In the same time, numerous studies have demonstrated that proteins can interact with and bind aroma compounds (Guichard 2006). ...
Interactions between saliva and flavour compounds
... 33 Buettner 22 reported the reduction of aldehydes to their corresponding alcohol after to reaction with saliva whereas alcohols remained unmodified. Some evidence have been reported for the hydrolysis of acetates and ethyl esters, 22,34 and for the oxidation of some thiols 22 as well as the interaction between some compounds (aldehydes, diacetyl, ethyl hexanoate, and heptyl acetate) and mucin. 35 However, the recovery of volatile compounds could not be attributed to direct actions of salivary constituents; chemical properties of the volatile compounds as well as the specific composition of food matrix and food/saliva ratio have crucial significance. ...
Volatile compounds are responsible of some sensory characteristics of virgin olive oil (VOO); however they have not been studied from the nutritional point view. In this work the effect of the simulated digestion on VOO volatile compounds responsible for green flavor was studied, analyzing their changes through the three steps of an in vitro digestion model (mouth, stomach and small intestine). Index of recovery and bioaccessibility were determined for the main volatiles of ‘Picual’ VOO. At end of the duodenal step higher recoveries of ethanol, pent-1-en-3-ol, β-ocimene and nonanal were observed. From the ten volatile compounds analyzed, only six compounds were bioaccessible. The compounds with the highest bioaccessibility were pent-1-en-3-ol, nonanal, β-ocimene and ethanol. The results showed for the first time the recovery and bioaccessibility of several volatile compounds present in VOO.
... A first study demonstrated that aroma release from white wines was more affected by saliva addition than for red wines. This lower effect of saliva on aroma release was attributed to the fact that tannins-salivary proteins complexes inhibited binding of aroma molecules to salivary mucins (Genovese, Piombino, Gambuti, & Moio, 2009). In a more recent study, it was observed in general a reduction of aroma release by saliva addition, but red wines were more affected than white wines. ...
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.
... Bakery products have extremely complex chemical compounds embracing both volatile and non-volatile substances, which relate to the flavor of the product. According to the bibliography, a large number of flavor research in bakery products are concerned with the analysis of volatile compounds (Hoff et al., 1978;Poinot et al., 2007;Genovese et al., 2009;Birch et al., 2013a). The flavor of the food can be recognized by use of sensory and instrumental approaches. ...
... Bakery products have extremely complex chemical compounds embracing both volatile and non-volatile substances, which relate to the flavor of the product. According to the bibliography, a large number of flavor research in bakery products are concerned with the analysis of volatile compounds (Hoff et al., 1978;Poinot et al., 2007;Genovese et al., 2009;Birch et al., 2013a). The flavor of the food can be recognized by use of sensory and instrumental approaches. ...
Recent studies of olfaction have highlighted the gap that separates physicochemical sensation and perception. Perception is a combination of models of reality, based on long experience, and sensory input. Such models typically incorporate visual, gustatory, and somatosensory (trigeminal) inputs. Once these patterns has been established, they can skew sensory input to conform to expectations. Thus, although it is desirable for consumers, and necessary for wine assessors, to develop prototypic sensory memories of particular wine types and age effects, it is critical that tasters guard against these constructs from warping what is actually being detected. One of the most intriguing aspects of olfaction is both its malleability (being strongly influence by extrinsic factors, notably the context under which the wine is sampled), but also the strong influence of experience-based percepts. Olfactory attributes are alternatively described in “concrete” terms (descriptors such as fruity or floral) or assessed using holistic (artistic) terms. Attempting to correlate these expressions with the chemical nature of a wine is fraught with multiple difficulties, both technical and perceptive, and may never be resolved. Nonetheless, one of the principal goals of sensory analysis is to make such correlations. Without it, aiding grape growers and winemakers to understand the basis of consumer likes, and how to adjust vineyard and winery procedures to produce wines that will be appreciated will remain severely restricted.
This is the first book for some years that provides a comprehensive overview of food oral processing. It includes fundamental chapters at the beginning of each section to aid the understanding of the later more specific oral processing chapters. The field is rapidly developing, and the systems researched in the context of food oral processing become increasingly complex and therefore the fundamental sections include information on how to build complex food systems.
The main coverage includes the biomechanics of swallowing, the biophysics of mouthfeel and texture as well as the biochemistry of flavours and how food microstructures can be manipulated. It contains up-to-date research findings, looking at consumer preferences and the response to these preferences by food process technologists and those developing new foods.
The book will be of interest to postgraduate students and researchers in academia and industry who may be from very diverse backgrounds ranging from food process engineers to functional food developers and professionals concerned with swallowing and taste disorders.
This is the first book for some years that provides a comprehensive overview of food oral processing. It includes fundamental chapters at the beginning of each section to aid the understanding of the later more specific oral processing chapters. The field is rapidly developing, and the systems researched in the context of food oral processing become increasingly complex and therefore the fundamental sections include information on how to build complex food systems.
The main coverage includes the biomechanics of swallowing, the biophysics of mouthfeel and texture as well as the biochemistry of flavours and how food microstructures can be manipulated. It contains up-to-date research findings, looking at consumer preferences and the response to these preferences by food process technologists and those developing new foods.
The book will be of interest to postgraduate students and researchers in academia and industry who may be from very diverse backgrounds ranging from food process engineers to functional food developers and professionals concerned with swallowing and taste disorders.
Can variation in wine preference amongst consumers be explained by salivary protein composition?
The present study aimed to define the interest in using a mastication simulator to understand the release of aroma compounds of biscuits in the mouth. The development of aroma compounds during artificial, human mastication and without masticated samples of veritable biscuits was determined. Then, the evaluations of aroma compounds in different types of biscuits were studied. A total of 32 compounds were identified in the veritable sample while 36 were identified in both sugar‐free and organic samples. The aldehydes and pyrazines were the main chemical groups in the samples. The number of aroma compounds in the biscuit samples revealed essential changes during mastication and increased about 2,5 times. Additionally, the presence of artificial and human saliva showed a similar effect. They increased the number of volatiles while influencing some volatile groups either by increasing the quantity of ketones or decreasing acids, alcohols, and aldehydes.
During wine drinking, aroma release is mainly impacted by wine matrix compositions and oral physiological parameters. Notably, tannins in wine could interact with saliva protein to form aggregates which might also affect the volatility of volatiles. To explore tannins, saliva, and the interaction between them on the volatility of volatiles, the volatility of 16 aroma compounds in the model wine mixed with the commercial tannin extracts, human saliva, or both respectively, was evaluated in vitro static condition by using HS-SPME-GC/MS. The volatility of aroma compounds with high hydrophobicity or benzene ring appeared to decrease more when increasing the tannin levels. Specifically, the volatility of ethyl octanoate, β-ionone, and guaiacol was decreased more than 20% by adding 2 g/L tannin extract. The addition of human saliva could significantly inhibit volatility of most aroma compounds in the model wine. Furthermore, the volatility of most aroma compounds in the mixture of tannins and human saliva was significantly lower than the control or the sample which were added with tannins or human saliva individually. The volatility of some aroma compounds in the mixture of the tannin and saliva was only around 50% or less, relative to the control. Two-way ANOVA analysis showed that there was a synergistic effect between tannin and saliva on decreasing the volatility of most aroma compounds (p < 0.05). Overall, understanding the effect of key factors such as tannins and saliva on volatility of volatiles could help to understand the sophisticated retronasal perceptions during wine tasting.
Practical Application
The outputs of this research will be helpful in understanding the impact of tannins on retronasal aroma release during wine tasting. It might promote the control of tannins in the viticulture and brewing process to improve the retronasal perception of wine aroma.
As one of the most popular traditional spirits in China, baijiu has a unique food matrix with high ethanol concentration and a wealth of aroma compounds. The aroma profile volatilized from the cup that has been widely studied may be different from the aroma that consumers perceived during drinking. It is affected by numerous factors, and saliva is a critical one. This study revealed that ex-vivo saliva had a significant positive or negative influence on ester release in simulated solutions, and proved that the degree of effects was related to the hydrophobicity of the compounds. Moreover, the ethanol concentration of simulated baijiu could alter the effect of saliva on esters. Both the effect intensity and the result would be changed, and the performance of the esters was related to their log P-value. Then we examined the underlying mechanism between saliva components and esters under the effect of diverse ethanol concentrations in simulated baijiu solutions with diverse buffers. The high ethanol concentration of baijiu may make the impact of saliva components on the ester release changeable and different from other food matrices because of the chemical and biological change in this system.
Background
Flavored wine is a type of specialized wine fortified with flavor additives such as herbs, spices, fruits and other natural flavorings, which has attracted increasing attention. In practice, the addition of flavor substances in winemaking is strictly regulated in many countries.
Scope and approach
This review evaluates traditional flavored wines in terms of history, botanical recipe, processing technique and sensory quality, and explores emerging flavored wines in the aspects of flavor additives, aroma profile and sensory properties. Additionally, the interactions between phenolic compounds and aroma compounds in flavored wines and their impacts on product quality are also discussed.
Key findings and conclusions
Traditional flavored wine, such as Vermouth, Bermet and Retsina, is among the most renowned alcoholic drinks. Basically, it is a blend of wine, botanical extracts, sugar and alcohol. Different parts (peel, seeds, flower heads, etc.) of aromatic plants (wormwood, cinchona, pine resin, etc.) are adopted as flavor additives, but with different combinations and proportions in recipe from company to company. At present, research on novel flavored wine is still at the early stage, although the inclusion of Ganoderma lucidum extract, Gentiana lutea root powders, grape skin extract, fruit juice, rice, dextrin, water and oak chips in winemaking have been proved to be successful in enhancing the aroma/flavor of wine and improving the mouthfeel. Addition of non-grape materials could introduce additional phenolics and aromatic compounds to the wine matrix, which is a critical factor impacting the flavor and palate of the flavored wine. Importantly, phenolics from non-grape materials may interact with saliva and oral mucosa and therefore has a prominent impact on the wine aroma volatility and thus wine organoleptic quality. In general, both traditional flavored wine and novel flavored wine are specially fortified wine characterized by the unique aroma and flavor of additional flavorings such as herbs, spices, fruits and other natural flavoring substances. This review provides comprehensive information on both old-fashioned and emerging flavored wines, which may trigger further investigation to exploit the potential of natural flavorings in winemaking.
Gas chromatography–ion mobility spectrometry (GC–IMS) and dynamic quantitative descriptive analysis (D-QDA) were combined to explore the aroma release and perception from the retronasal cavity during bread consumption. D-QDA results elucidated that the sweet, creamy, and roasty notes were the most active attributes during oral processing. The final stage of oral processing had the most complicated changing pattern, followed by the intermediate and initial stages. Thirteen aroma compounds were detected in the retronasal cavity, of which eight had odor activity values (OAVs) greater than 1. The total OAV changing pattern was consistent with the D-QDA results. Addition experiments further confirmed that acetoin, 2,3-butanedione, and 3-(methylthio)propanal were key aroma compounds contributing to retronasal olfaction. 2,3-Butanedione and 3-(methylthio)propanal were both identified as key odorants in the mouth cavity and retronasal cavity during oral processing, but they had 30% loss during the breath delivery from the mouth cavity to the retronasal cavity.
Wine aroma profiles are determinant for the specific style and quality characteristics from final wines. These are dependent on the seasonality, mainly weather conditions, such as solar exposure and temperatures and water management strategies from veraison to harvest. This paper presents machine learning modeling strategies using weather and water management information from a Pinot Noir vineyard from 2008 to 2016 vintages as inputs and aroma profiles from wines from the same vintages assessed using gas chromatography and chemometric analyses of wines as targets. Results showed that artificial neural network models (ANN) rendered the high accuracy in the prediction of aroma profiles (Model 1; R = 0.99) and chemometric wine parameters (Model 2; R = 0.94) with no indication of overfitting. These models could offer powerful tools to winemakers to assess aroma profiles of wines before winemaking, which could help to adjust some techniques to maintain/increase quality of wines or wine styles characteristic of specific vineyards or regions. These models can be modified for different cultivars and regions by including more data from vertical vintages to implement artificial intelligence in winemaking.
In order to determine if inter-individual differences in saliva composition and flow influence the perception of specific aromatic stimuli elicited by esters after wine consumption, ten individuals were selected and instructed in the recognition of four aromatic stimuli elicited by four ester compounds, which were added to a rosé wine. The whole panel was firstly characterised by their salivary flow, composition (pH, total protein content, macro- and micro- minerals) and rheological properties (viscosity), and secondly, the panellists were trained in a dynamic sensory method for the evaluation of retronasal aroma intensity at discrete time intervals (5, 60, 120, and 180 s) after wine expectoration. Significant inter-individual differences (p < 0.05) in saliva composition were found in most salivary parameters. Differences in the intensity ratings among individuals were also found for the four aroma attributes. Spearman correlation analysis between saliva parameters and aroma intensity over time showed a strong positive correlation between salivary flow and aroma perception for some aroma and time points. This correlation was higher in the immediate than in the long lasting perception and greater for aroma attributes elicited by short chain length esters (isoamyl acetate, ethyl butanoate and ethyl hexanoate) (than for attributes elicited by larger esters (ethyl decanoate).
An in-mouth headspace sorptive extraction (HSSE) procedure for the in-mouth volatile sampling of wine aroma compounds during wine tasting has been developed. The procedure is based on the application of a PDMS (polydimethylsiloxane) twister contained inside a tailored made glass tube placed into the headspace of the mouth after rinsing and spitting-off the wine, which is then followed by gas chromatography mass spectrometry analysis (GCMS). Various parameters that might affect the performance of the method (extraction time, aroma concentration) were firstly investigated. Despite the short selected in-mouth extraction time (30 s); the application of the in-mouth HSSE procedure using real wines allowed the detection of >30 volatile compounds from different chemical families in the oral cavity in a single run, and which are also present in the wine at very low concentrations. Additionally, the in-mouth HSSE profile allowed us to distinguish between wines types (with different non-volatile and volatile composition) in a similar way to that when using data from the headspace of the wine (wine-HSSE-GCMS). The simplicity, sensitivity, good repeatability and the easy automatization of this procedure, makes this technique a reliable and feasible tool to determine the chemical and biochemical changes of these compounds in the mouth in real physiological conditions providing useful –in vivo analytical data to better correlate with sensory studies.
Background:
Early leaf removal at pre-bloom is an innovative viticultural practice for regulating yield components and improving grape quality. The effects of this technique on vine performance, grape composition and wine sensory profile of Semillon variety were assessed.
Results:
Pre-bloom leaf removal enhanced canopy porosity, total soluble solids in musts and reduced cluster compactness. This practice had a strong effect on glycoside aroma precursors, in particular by increasing glycoside terpenols and norisoprenoids. Metabolites of linalool were the most responsive to leaf removal. Wine produced from defoliated vines was preferred in tasting trials for its more intense fruity notes and mouthfeel attributes.
Conclusion:
Pre-bloom leaf removal is a powerful technique for modifying canopy microclimate, vine yield, grape composition and wine quality. The increase of glycoside aroma compounds in treated grapes has potential positive effect in improving the sensory profile of the resulting wines.
Background
Saliva is a complex fluid with multifunctional roles in the oral cavity. Even though its importance on oral health maintenance has long been recognized, the critical functions of saliva on food oral processing and perception have only been acknowledged recently.
Scope and approach
This review will present saliva as an unavoidable ingredient that has a profound impact on our eating experience. We aim to emphasize that what is perceived in-mouth is a food-saliva mixture rather than the food on the plate. The mechanisms through which saliva interacts with food components will be discussed in detail together with the implications of food-saliva interactions to food oral processing and perception.
Key findings and conclusions
At the structural level, saliva facilitates the breakdown of food structures, contributes to the formation of a cohesive bolus and increases the degree of lubrication for a safe swallow. At the molecular level, saliva interacts with food components, leading to the formation of new compounds, complexes and microstructures. The mechanisms underlying food-saliva interactions include surface coating and clustering, colloidal interactions, complexation, enzymatic breakdown and binding of aroma compounds.
In this chapter, we will briefly describe the complexity of the main mechanical, biochemical and physicochemical phenomena that occur in the mouth during food consumption using examples. To better understand the reactions occurring in the mouth during food consumption, in vitro systems called model mouths were developed to simulate food consumption and thus answer some of the more fundamental questions regarding olfactory perception. This chapter provides examples of the applications of the model mouth in performing oral functions, such as mastication, saliva production and airflow, as well as swallowing, while the released volatile compounds are measured. The recent model mouth designs represent the actual occurrence of food consumption under oral conditions in a more accurate way. We believe that this type of methodology will be even more commonly applied in the future to improve the knowledge in this field.
Aroma is the major contributor to overall flavor perception and it is one of the most important intrinsic factors that influence wine quality and consumer preferences. Therefore, a great amount of work in wine chemistry has been devoted to identify wine volatile compounds and to improve the analytical methodologies for this purpose. However, we already know that not all of these compounds have aroma impact. To determine the odorant importance of wine volatile compounds, and therefore its impact in aroma perception and consumer preferences, we need to go one step forward incorporating studies concerning the sensory relevance of wine volatile compounds and understanding other aspects related to interactions among odorants, or among sense modalities, which can also affect the perceived aroma of a wine. Moreover, the existence of matrix effects can impact odorant volatility, aroma release, and the overall perceived aroma intensity and quality. Finally, the effect of human physiology and specifically oral physiology on wine aroma release during wine consumption is currently under study, and it is being proven as an important factor to explain interindividual differences in wine aroma release during wine intake, which might impact aroma perception and wine preferences. This chapter provides an overview of the current state of knowledge of all these aspects giving special attention to the new and merging research in the abovementioned topics.
This study aimed at isolating and culturing Bacilli from the omagari, pit mud, and fermented grains used in Luzhou-flavor liquor in an effort to produce better flavor and quality. After an enrichment culture of Bacillus in the omagari, pit mud, and fermented grains of Luzhou-flavor liquor, 52 total strains were obtained. Based on the standard of producing high-yield ethyl hexanoate and low-yield propanol, one strain named YB-1 was screened out. It was shown that YB-1 produced ethyl hexanoate at 214.7 mg/100 mL and propanol at 0 mg/100 mL. Based on strain morphology, and physiological and biochemical characteristics, YB-1 was identified as Bacillus. According to DNA sequencing and the constructed phylogenetic tree, YB-1 and Bacillus cereus strain CCM 2010 clustered into a branch and were each other's closest relatives. Thus, YB-1 was identified as Bacillus cereus. Through this research, it is expected that the application of Bacillus cereus strain YB-1 to the traditional brewing process of Luzhou-flavor liquor could improve the flavor and quality, and enrich microbial resources for Luzhou-flavor liquor fermentation.
Flavour is perceived as the result of partition and equilibrium of volatile odorants of a food during consumption. Research previously carried out with whisky has been restricted to sensory and conventional chemical analyses, which have made a contribution to understanding the process, but cannot show what happens when whisky is consumed. Dynamic headspace methods are required to take a step further into understanding the phyco-chemical interactions that take place in the mouth of the consumer or laboratory assessor. Buccal headspace analysis has been used for whiskies, but cannot be used for model systems of non-food materials. The “Simulated Mouth” was therefore designed and constructed to imitate the mouth.
Operation of the simulated mouth was optimised using buccal headspace analysis as a reference method. Parameters that were taken into consideration were: the flow rate of hydrated air through the simulated mouth cavity, presence of artificial saliva, the size of the vessel, the amount of whisky used, the use of glass beads to simulate teeth, shaking or static condition, and the time for collection of volatiles. The simulated mouth showed systematic changes in a series of samples of different maturation times. The arrangement of the model and the methodology should also be appropriate for study of flavour release from other liquid systems.
This paper aimed to characterise and compare the changes in champagne aroma with aging, in normal or accelerated conditions (at 40 degrees C), by sensory, GC-O and GC-MS analyses. Initially, extract representativeness was tested by triangle and similarity tests and descriptive profiles were established for young and aged samples by a expert panel. The intensity of floral and fruity notes were shown to decrease with aging. Oak and evolution characters increased, although there were some other sensory differences between the two aged products. GC-O differences could be related to several phenomena. Three processes were characteristic of normal aging: firstly, the Strecker reaction of amino acids to produce 3-(methylthio)-1-propanal and ethyl furaneol; secondly, the generation of eugenol, and thirdly, the oxidation of sensitive flavor compounds such as furaneol. Other processes were also characteristic of accelerated aging: the degradation of unsaturated fatty acids to form cis-3-hexenol; the formation of 2,3-butanedione and guaiacol; and the metabolism of phenylalanine to produce benzaldehyde. So, although common types of reactions were present in both aging methods we can conclude that champagne heating is not an aging method which is identical to the standard technological aging procedure.
Although flavour glycosides have been reported in wine, the possibility that they might contribute to perceived flavour by being hydrolysed in the mouth during consumption has not been previously documented. The release of hexanol from hexyl β-d-glucoside was studied in-mouth by measuring hexanol in expired air with atmospheric pressure ionisation–mass spectrometry. About 10% (0.2mg) of the glucoside was hydrolysed over a 2min period due to the activity of glucosidase enzymes from the oral microflora. Since wine contains ethanol, the inhibitory effects on alpha and beta glucosidases from different sources were ascertained using p-nitrophenyl glucosides and spectrophotometric determination. Enzymes from yeast and almonds were inhibited to a greater extent (70–80%) than the Aspergillus niger enzyme (35%). Overall, the results show that there is potential for flavour glycosides to be hydrolysed in-mouth and therefore contribute to perceived flavour but further work in real food systems is needed to confirm this hypothesis.
Saliva samples were collected from 12 panellists immediately before and after the sensory assessment of two red wine samples and the salivary proteins in all samples were analysed by high performance liquid chromatography (HPLC). Three peaks appeared in the majority of the chromatograms and the areas of these peaks were individually correlated for each assessor against four astringency time–intensity (T–I) parameters (time to maximum intensity, total duration, maximum intensity and area under the T–I curve). Astringency was not correlated with the total area in the saliva chromatograms. However, statistically significant correlations were obtained between the area of particular proteins and the sensory data indicating that the concentration of individual proteins in saliva might be more important for astringency than the total protein content. Significant correlations were also obtained between the relative concentration of individual proteins and the T–I data.
SDS–PAGE electrophoresis and densitometry analysis were carried out to evaluate the reactivity of Aglianico red grape skin and seed polyphenols with human salivary proteins in order to find a method able to assess their astringency. Analysis of the supernatant obtained after a tannin/human salivary protein binding assay and sensorial analysis showed that four proteins, lactoferrin, PRPbg1, PRPbg2 and α-amylase, were the proteins best able to distinguish tannin solutions characterised by different levels of astringency.A correlation between densitometric data and tannin concentration was plotted in order to give an indirect measure of astringency. The two sources of Aglianico grape polyphenols differed from each other in astringency power; the seed extract solution was about two-fold more tannic than the skin one. The difference in astringency was also perceived by sensorial analysis.The results from this study show that SDS–PAGE electrophoresis of human salivary proteins after the binding reaction with grape polyphenol extracts, coupled with densitometric analysis and the use of a calibration curve, looks extremely promising as a new approach to evaluate polyphenol astringency.
The subject of flavour-matrix interactions in foods is tremendously broad and involves chemical and physical interactions of many different types. Flavour molecules can be volatile or non-volatile compounds and the food matrices range from water to complex biological tissues like meat. While the physical properties of the flavour compounds are important in determining their interaction with the matrix, the state of the matrix is equally important. An example is starch, which can be present in foods as a viscous solution (e.g. a sauce), a rubbery solid (e.g. bread dough) or a glass (e.g. a low moisture snack product). Trying to generalise the interaction of a volatile with starch in all its forms is not practicable and consideration of the physical state, the mechanism of the interaction and other parameters like water content and temperature is essential. Some food ingredients have been extensively studied, while others are considered difficult and have been largely ignored. One of the factors limiting research is the lack of a complete set of physical data (solubility, vapour pressure etc.) for the many compounds associated with flavour. Because of the complexity of the interactions and the lack of physical data, some workers have approached the problem by investigating complex real food systems, followed by analysis of the data to determine the key physicochemical factors involved in the flavour-matrix interactions. Other researchers have attempted to study complex systems using a fundamental approach based on defined mechanisms. Both approaches have yielded useful data.
Flavour is perceived as the result of partition and equilibrium of volatile odorants of a food during consumption. Research previously carried out with whisky has been restricted to sensory and conventional chemical analyses, which have made a contribution to understanding the process, but cannot show what happens when whisky is consumed. Dynamic headspace methods are required to take a step further into understanding the phyco-chemical interactions that take place in the mouth of the consumer or laboratory assessor. Buccal headspace analysis has been used for whiskies, but cannot be used for model systems of non-food materials. The "Simulated Mouth" was therefore designed and constructed to imitate the mouth. Operation of the simulated mouth was optimised using buccal headspace analysis as a reference method. Parameters that were taken into consideration were: the flow rate of hydrated air through the simulated mouth cavity, presence of artificial saliva, the size of the vessel, the amount of whisky used, the use of glass beads to simulate teeth, shaking or static condition, and the time for collection of volatiles. The simulated mouth showed systematic changes in a series of samples of different maturation times. The arrangement of the model and the methodology should also be appropriate for study of flavour release from other liquid systems.
Perhaps the single most important criterion for consumer acceptance of foods is flavor. Proteins have little flavor of their own, but influence flavor perception via binding and/or adsorption of flavor compounds. Protein ingredients both transmit undesirable off-flavors to foods and reduce perceived impact of desirable flavors. This behavior is an important consideration in the design of food flavors, especially those intended for lowfat food formulations. Data from model systems illustrate that several factors determine the extent of interaction between proteins and food flavors, including the chemical nature of the flavor compound, temperature, ionic conditions and the structure and processing history of the food protein. Continued systematic study in this area will allow the optimal design of flavors for new formulated foods, elimination of transmitted off-flavors and development of efficient flavor carrier systems.
A beef flavouring prepared at three levels of concentration and presented at three temperatures has been profiled, comparing nasal (sniffing) and oronasal (buccal) perception in relation to changes of taste by addition of NaCl and MSG. Aroma concentrations are better discriminated when perceived through the mouth than through the nose. On the other hand, the effect of temperature is more perceptible through the nasal pathway than through the oronasal pathway; the different characteristics of odour change in different ways with temperature, some increase, others decrease, inducing changes in odour quality. Addition of NaCl and MSG seems to enhance odour intensity, spicy and meaty notes but reduces the effect of temperature on odour perception. NaCl enhances the total flavour intensity, and smooths the mouth sensation, decreasing the negative characteristics (metallic note) and increasing the positive ones. MSG enhances very slightly the global flavour intensity but has no effect on the aromatic notes (meaty, vegetable, fatty).
Nasal and retronasal olfactory perception were compared at two levels: perception threshold and supra-threshold concentrations. Three methods of stimulation were used: direct stimulation (sniffing) and indirect stimulation (inhaling the vapour phase or sipping the odorant). The tests were performed with aqueous solutions of two flavours giving the sensation of being a specific taste: citral and vanillin. Perception thresholds, measured by a sorting method with a triangle presentation, showed that the three pathways of stimulation differ in their efficiency. Sipping the solution, sniffing and inhaling through the mouth give increased thresholds. For supra-threshold intensities, measured by magnitude estimation against 0.05% n-butanol reference, we again found the same trend. These different efficiencies are examined in relation to airflow through the nasal cavity and the temperature of the stimulus. The slope of Stevens' regression lines were identical for sniffing and inhaling, showing that olfactory perception by direct or retronasal pathways involves the same mechanism. For sipping the solution, the slope is rather different due to adaptation or trigeminal stimulation.
Classical analyses for volatile flavors (headspace or distillation/extract methods) give information on either the volatiles present in the air above a food before eating or the total volatile composition of the food. When foods are eaten, however, many changes take place (such as hydration/dilution with saliva, increase in surface area, etc.) that affect the release of volatiles from the food and therefore the profile of volatiles that are sensed in the nose. If we wish to study the relationship between flavor volatiles and the sensory properties of a food, it seems logical to measure the volatile profile that exists during eating. Although volatile flavor release during eating has been measured using a variety of sensory and psychophysiological analyses, only recently have instrumental methods been developed to measure the release of volatile compounds in humans as they eat. Whereas the sensory data give an overall measure of flavor perception, instrumental analyses can potentially follow the release of each and every flavor volatile and thus give a full picture of the aroma profiles generated during eating. From these instrumental measurements, a number of key factors have been identified. First, it has been shown that the volatile profile measured during eating is indeed different from the headspace profile of whole foods. Second, it is clear that the volatile profile in‐mouth changes with time as the state of the food changes with chewing. Third, the volatile release from low‐water foods is affected by the rate and extent of hydration in‐mouth. The ability to measure aroma before, during, and after eating may lead to an understanding of the links between aroma release, interaction of volatiles with aroma sensors in the nose, and the overall perception of food flavor.
The effect of artificial saliva components on flavour release from dehydrated diced red bell peppers (Capsicum annuum) was studied in a mouth model system. This measured the dynamic headspace under oral conditions, such as temperature, volume of the mouth, salivation, and mastication (DHM). The results were compared with a dynamic headspace (DH) and a purge-and-trap (PT) model system. Volatile compounds were analysed by gas chromatography, using flame ionisation detection (FID), mass spectrometry (MS), and sniffing port detection (SPD). SPD revealed that only 12 of the 47 compounds identified by MS and FID possessed odour activity. For all saliva compositions FID peak areas of volatile compounds were largest in the PT system, followed by DHM and DH, respectively. In the PT system the less volatile compounds were relatively better released than other volatile compounds in comparison with the DHM and DH system, for all salivas. The saliva components mucin and α-amylase caused a relative decrease in release of the less volatile compounds in all model systems. An overall decrease in FID peak areas of volatile compounds by the latter components was observed in model system DH only.
The formation of flavor in fermented beverages is due to various biosynthetic mechanisms. In wine, flavors arise as the result of compounds: 1. Originating from the native fruit (grap) 2. Which are formed or altered during the various processes employed in production 3. Which are developed or transformed by yeast during fermentation 4. Arise during the aging process In this review the results of investigations on the development of flavors in grape and wine will be discussed. Special attention will be devoted to the effects of specific processes in winemaking on the development of flavor.
A total of 38 volatile components from 90 white wines stored under uncontrolled temperature conditions in the marketplace were analysed. The composition of volatiles in the wines changed with storage time, namely, the concentration of isoamyl acetate and ethyl 4-hydroxybutyrate decreased and the concentration ethyl lactate, diethyl succinate, ethyl monosuccinate, and diethyl malate increased. Sensory and chemical changes were less pronounced in wines stored chilled (5 °C), suggesting that chilled storage may be used to increase the shelf life of young white wines.
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 influence of human whole saliva on selected alcohols, aldehydes, 3-alkyl-2-methoxypyrazines, and phenols in food-relevant concentrations was investigated. At pH 7.5-8 it was found that the alcohols, methoxyphenols, methoxypyrazines, and 3-hydroxy-4,5-dimethyl-2(5H-)-furanone remained unmodified by saliva, whereas aldehydes were reduced to their corresponding alcohols. Generally, the processes were found to be dependent on the salivary activity of the panelists as well as on the concentration of the applied odorants. Reduction of the aldehydes did not occur after thermal treatment of the saliva. These investigations are aimed at finding an explanation for longer lasting aftertaste in humans, as it is induced by some odor-active compounds after the consumption of food materials.
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.
Nor-isoprenoid compounds, such as β-damascenone, β-ionone, 2,2,6-trimethylcyclohexanone (TCH), 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) and vitispirane were determined in 14 young port wines and 45 old port wines. As between the two groups of wines levels of these compounds are quite different, an experimental protocol was performed in order to determine which technological parameter (dissolved O2, free SO2 levels, pH and time/temperature) was related with the formation/consumption of these molecules. The five nor-isoprenoids were equally affected by the selected parameters and a similar profile with time was observed. The synergistic effects of increasing temperature and lowering pH had the largest impact. For samples treated with high oxygen regimes (saturation), the levels of all considered nor-isoprenoids decreased after a certain concentration of oxygen consumed (e.g. 10mgl−1).Nevertheless, during barrel port wine ageing, corresponding to the 45 wines, two different behaviours can be observed: TDN, vitispirane and TCH increase significantly whilst a decrease of levels of β-ionone and β-damascenone with port barrel ageing was observed. It was also calculated that “over 40 year” old port wines have, respectively, 15, 5 and 3 times higher levels of TDN, vitispirane and TCH than the young ports. For these three compounds the respective rates of formation are higher than those of degradation, which suggests a higher number or higher concentration of precursors than those involved for the megastigame C13 nor-isoprenoids β-damascenone and β-ionone.
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.
Free and bound aroma compounds of eight Spanish grape cultivars (Albariño, Treixadura, Listan, Viura, Xarel.lo, Parellada, Garnacha, and Tempranillo) used in winemaking were studied. With a single-extraction procedure it was possible to provide information about the potential flavor of these varieties: bound aroma was determined directly by TFA glycoside analysis and indirectly by enzyme hydrolysis release of aglycon. An aroma data base of these varieties and a comparison between the grape flavor composition of each variety were established. Grape characteristics (sugars, acidity, polyphenols, juice yield), mainly due to climate and cultivar factors, were related with the aroma composition. Non-terpenyl compounds such as 2-phenylethanol and benzyl alcohol were the main glycosidically bound compounds of Spanish varieties. Direct determination of glycosides is better than hydrolysis of aglycon as an approach to the potential aroma of grapes. Keywords: Aroma; glycosides; Spanish grape cultivars; Albariño; ’Treixadura; Listan; Viura; Xarel.lo; Parellada; Garnacha; Tempranillo
A flavor release method using a “retronasal aroma simulator” (RAS) combined with gas chromatography olfactometry (GCO) was used to study the aroma of raspberries, Rubus idaeus cv. Heritage. Dynamic headspace samples were generated with the RAS including synthetic saliva addition and shearing at 37 °C. A headspace dilution series was sampled from the RAS and analyzed by CharmAnalysis GCO to produce measures of odor potency called charm. The most potent flavor compounds in fresh raspberries were β-damascenone, diacetyl, sotolon, 1-hexen-3-one, 1-nonen-3-one, 1-octen-3-one, and (Z)-3-hexenal. Heating raspberries caused an increase in raspberry ketone and rated raspberry aroma. Likewise, β-damascenone, sotolon, vanillin, 1-nonen-3-one, and 1-octen-3-one showed at least 5-fold increases in charm upon heating. Cream addition markedly decreased aroma (GCO and sensory). Comparison of the fresh raspberries odor spectra between RAS−GCO and solvent extraction−GCO showed different profiles, with the former having greater odor potency values for diacetyl, 1-hexen-3-one, 1-octen-3-one, 1-nonen-3-one, and sotolon and the latter with a greater value for ethyl 2-methylbutyrate. Keywords: Aroma; GC; retronasal; raspberries
The interaction between [14C]benzyl alcohol and denatured bovine serum albumin or Soyamin 90, chosen as models for food proteins, was shown to be reversible adsorption of the flavor compound on the denatured protein. Adsorption is directly proportional to the amount of protein and increases linearly with increasing flavor concentration. Adsorption can be decreased slightly by suspending the denatured protein in media containing dissolved protein or lipid material. Adsorption is reduced by 50% when the denatured protein is suspended in media containing both dissolved protein and lipid material, such as caseinate-stabilized oil/water emulsions, aqueous coffee whiteners, or milk. Adsorption isotherms are given for these and other model systems.
The binding of a homologous series of aldehydes and methyl ketones by various food proteins was studied in model systems by headspace analysis using gas chromatography. The amount of flavor bound depended on the type, amount, and composition of the protein, and the presence of solvents such as water and lipids. The addition of water to proteins, i.e., α-lactalbumin, bovine serum albumin, leaf protein concentrate, single-cell protein, and various soy protein preparations, decreased the volatilities via increased adsorption or solubilization of flavors by the protein-water mixture. The concentration of headspace volatiles in model systems containing flavor and leaf protein concentrate increased upon removal of lipids. Flavor binding by the concentrate, isolate, and textured forms of soy protein was influenced by their compositions. The effect of proteins on volatility was similar in systems containing either dilute or concentrated flavors.
Salivary proline-rich proteins have a high affinity for tannin and protect against the antinutritional effects of dietary tannins. Several of these proteins are glycosylated so we have investigated the role of the carbohydrate in their binding to tannin. The results suggest that oligosaccharides enhance the affinity and selectivity of binding to tannins and increase the solubility of the resulting tannin/glycoprotein complexes.
Flavour compounds are released at different times and with differing rates during cheese consumption. This aspect of flavour has received little attention, although it is likely to be of great importance in the perception of hard cheese flavour. Full-fat and reduced-fat hard cheeses were analysed by standard buccal headspace methodology and by conventional descriptive sensory analysis. Cheeses were further analysed by ‘time-concentration’ buccal headspace methodology and sensory time–intensity analysis. Conventional data distinguished between individual cheeses and between fat contents. Time-course data confirmed the results of conventional analysis, but also allowed the examination of release behaviour and changes in flavour perception with time. Partial least squares regression was successful in predicting some sensory attributes from standard buccal extracts. Time-course studies improved predictive ability.
Analyses for trace flavorants in the mouth were performed by extraction of aqueous mouth rinses with methylene chloride, concentration of the extract, and gas chromatographic analysis of the concentrate. Trace flavorants were determined after chewing peppermint-flavored gum and after rinsing with mouthwashes. The durability of several flavorants in the mouth was compared. The data obtained show that flavorants differ in their retainability in the mouth, as judged from the amount of their residuals. Menthol and anethole are retained longer than most common flavorants. Flavor esters are partially hydrolyzed in the mouth to give the corresponding alcohols. Aldehydes are also affected and produce their corresponding alcohols.
A technique for direct measurement of the differential diffusion coefficients in a ternary system of water, sugar, and a dilute organic species is described. The individual sugars were d-fructose, d-glucose, and sucrose; and ethyl alcohol, ethyl acetate, n-butyl acetate, and n-hexanal individually constituted the dilute organic species. The four ternary diffusivities were obtained over a range of sugar concentrations by the use of horizontal diaphragm cells, a differential interferometer, a flame-ionization gas-liquid chromatograph and postulation of the validity of the Onsager reciprocal relations. The equilibrium partial pressures of the dilute organic species over these solutions have also been measured, using a vapor head space chromatographic technique.
Seventy-six enzyme activities of mixed whole saliva, parotid saliva, serum, and polymorphonuclear leukocytes were examined in 10 individuals with healthy periodontium, 10 adult periodontitis patients, and 4 localized juvenile periodontitis patients by using the API ZYM (Analytab Products Inc., Plainview, N. Y.) and API ZYM AP (API System, La Balme les Grottes, France) semi-quantitative micromethod systems. Enzymes assayed included phosphatases, esterase, lipase, glycosidases, and proteases including numerous aminopeptidases.
Among the three study groups, mixed whole saliva of adult periodontitis patients revealed the highest and mixed whole saliva of healthy individuals the lowest enzyme activities. Statistically significant differences were found for alkaline phosphatase, esterase, β-glucuronidase, α-glucosidase, and some aminopeptidases. Bacterial sediment of whole saliva exhibited higher enzyme activities than whole saliva supernatant. Serum contained numerous aminopeptidases which were virtually undetectable in whole saliva. Some enzyme activities found in mixed whole saliva could not be detected in parotid saliva. Polymorphonuclear leukocytes demonstrated a distinct enzyme profile.
The present study shows that varying enzyme profiles exist among the various components which make up whole saliva. It also indicates that numerous salivary enzymes originate from oral microorganisms and that the enzyme activity of whole saliva is higher in individuals with periodontal disease than in periodontally healthy subjects.
The release of aromas during the eating of mint-flavoured sweets was investigated by collecting part of the expired air flow (nose-space) from human subjects at 10-s intervals over a 5-min period and determining the amounts of 11 key volatiles by GC-MS. No attempt was made to standardize eating patterns. Variations in aroma release between people were investigated in two ways: by measuring the total amount of volatiles released (sum of the 11 peak areas) and by analysing the release of three volatiles, limonene, menthone and menthol, during the chewing and sucking of mints. In the chewing experiments, the total volatile concentration in the nose-space was greatest between 20 and 50 s, which corresponds to the point at which the mints were swallowed. However, some volatiles did persist after swallowing. In the sucking experimentas, the total volatile trace persisted for up to 300 s for some subjects as the mint was still present. For the three individual compounds, the amounts released were expressed as a percentage of the total peak area and this produced very similar traces from the four people in the experiment. There were distinct differences in the time-release curves for the three compounds which may be related to the polarities and boiling points of the volatiles in the mint/saliva system that exists in the mouth. Release of the three compounds when mints were sucked resulted in a slower release of all three volatiles compared to chewing. The variation in aroma release was estimated by analysing the amount of limonene present in the three replicates of breath samples of four people at each point of the time course. Variation in the mean amounts of limonene released (measured as the percentage coefficient of variation %CV) was relatively high (%CV ranged from 5.2% to 62.4%), but this was probably a consequence of short sampling times and the different routes of airflow in humans during eating.
Perceived intensities of aqueous solutions of 0.01% citral (C) and of 0.14% vanillin were estimated over time when presented nasally (sniffing), retronasally (sipping) and orally (sipping with nose pinched). the onset and decay of nasal perception was very rapid, with maximum intensity reached between 4-8s and extinction between 9-15s. the oral response was extremely low, while retronasal intensity reached maximum 11-19 s after stimulation with a duration ranging from 40 to 120s. Orally, 10 of 19 subjects rated solutions containing C and citric acid (CA) significantly higher than those containing CA alone. Retronasally, citral intensity was enhanced by CA > CA + sucrose (SUC) > SUC > NaCl. Addition of xanthan gum had little effect on perception of citral. Retronasal intensity of vanillin solutions was increased by addition of sucrose (SUC) and depressed by CA and by NaCl. the results demonstrated large differences in perceived intensity and duration via the three procedures, significant alteration of oral intensity by added tastants, and marked bimodality of response upon the addition of acid to citral.
Free and glycosidically bound volatile compounds were isolated and identified from muscadine grape juice. Most abundant in free and bound form was the muscadine character-impact aroma compound 2,5-dimethyl-4-hydroxy-3(2H)-furanone (Furaneol). Other aroma compounds, such as o-aminoacetophenone and 2-phenylethanol were found in free and bound forms. A high level of 2-phenylethanol was intheglycosideformand many bound monoterpenes were identified. p-Vinylguaiacol, a potential off-flavor in muscadine juice was found at a low level in bound form. Enzymatic hydrolysis of glycoside precursors could lead to release of volatile compounds with both potentially positive and deleterious effects on the overall aroma.
The influence of medium composition on the release and volatility (vapour/liquid partitioning) of volatile lipid oxidation
products was studied in order to explain the differences in composition of volatiles released from oxidised sunflower oil
and its 40% oil-in-water emulsion in a model mouth system. Volatile compounds were analysed by gas chromatography combined
with flame ionisation detection and mass spectrometry. Larger amounts of volatiles, formed during oxidation, were released
from the emulsion than from the bulk oil. Differences in release influenced the results as well as the partitioning, but showed
contrary effects. Added reference compounds were released in larger quantities from the oil than from the emulsion in the
model mouth, and higher vapour/liquid partitioning values were obtained for the emulsion in comparison with the oil. In addition,
water and saliva components influenced the release of reference compounds in the model mouth and the partitioning, giving
different results for the oil and the emulsion. In conclusion, differences in the release of volatile compounds due to medium
composition influenced the composition of the volatile lipid oxidation products of sunflower oil and its emulsion, as well
as the lipid oxidation rate.