Orthonasal vs. retronasal: Studying how volatiles' hydrophobicity and matrix composition modulate the release of wine odorants in simulated conditions

Odor-induced saltiness enhancement of volatile compounds screened from duck stewed with chili pepper

Odor-induced saltiness enhancement (OISE) is thought to be a unique salt reduction technique which capitalizes on olfactory-gustatory interaction. Volatile compounds of stewed duck obtained from orthonasal (no-treatment) and retronasal (saliva-treatment) pathways and their capacity on OISE were analyzed by GC-O-MS and molecular simulation in order to ascertain the role of odors in duck stewed with chili pepper on saltiness enhancement. Totally 17 unique volatile compounds were identified in retronasal pathways. Eight salty-congruent volatile compounds were screened from the stewed duck, one of which being E-2-decenal, specific to retronasal volatile compounds following oral enzymatic digestion. These volatile compounds' OISE in NaCl solution was confirmed, and the retronasal pathway effect outweighed the orthonasal one. Molecular docking revealed that volatile compounds interacted with saltiness receptors through hydrogen bonding and hydrophobic force, which may be responsible for its enhanced saltiness. These findings suggest that olfactory pathways and specific odors might simultaneously mediate OISE.

Studying how dry extract can affect the aroma release and perception in different red wine styles

BACKGROUND

Four red wine matrices representing different red wine styles with the same VOCs (volatile organic compounds), were obtained by enriching a bleed wine with increasing amounts of deodorized dry extract obtained from the pressed wine of the same vinification. The release of VOCs was determined by solid phase micro-extraction-gas chromatography-mass spectrometry (SPME-GC-MS), in conditions mimicking those applied during sensory assessments.

RESULTS

Results show that even though the perception of the overall odor intensity was not significantly influenced by the matrix, this latter modulated the odor profiles: at rising wine dry extract, fruity, floral odors decreased, while dehydrated fruit, woody-toasty, vegetal-earthy notes increased. These changes cannot be fully explained by the observed significant influence of the matrix on the release of VOCs or by their correlations with the considered matrix components (ethanol, residual sugars, phenolics, pH), but findings suggest that perceptual interactions are involved.

CONCLUSION

This study could be useful in pressing and blending management for wine aroma quality also considering wine compositional trends under the current climate change context. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Use of vine-shoots stilbene extract to the reduction of SO2 in red and rosé Italian wine: Effect on phenolic, volatile, and sensory profiles

Sulfur dioxide (SO2) is one of the most used additives in wine industry for its antioxidant and antimicrobial activity. However, due to health concerns, consumers' demand of wines with either reduced or totally replaced SO2 has increased. This study aimed to assess the effect of partial and total replacement of SO2 with a vine-shoots extract rich in stilbenes in rosé (cv. Sangiovese) and red (cv. Negramaro) wines respectively. Color as well as phenolic, volatile, and sensory profiles of wines were evaluated at bottling and during storage. The results showed that the vine-shoots extract increased the levels of trans-resveratrol, catechin, and gallic acid in wines. Moreover, the positive correlation of procyanidin dimers in red wine suggested an increase of the polymerization reactions. The amount of added extract probably provided lower antimicrobial protection compared to SO2, as indicated by the higher levels of ethyl phenol. The decrease of individual anthocyanins and oxidation aldehydes observed in wines with SO2 replacement and the higher levels of caftaric acid in the rosé wine with the extract suggested a shift of the oxidative protection, with a lower protection towards anthocyanin degradation and higher protection towards carbonyl formation and oxidation of readily oxidizable phenolic acids.

Retronasal sensory characterization of aroma compounds in Baijiu by detection threshold measurement, retronasal OAVs, and time-intensity evaluation

The retronasal aroma of Baijiu is closely related to its quality and consumer preference. Retronasal detection thresholds (RDTs) of 44 aroma compounds were determined in 46% v/v ethanol using a three-alternative forced-choice procedure, which varied widely and ranged from less than 0.02 to over 1,000,000 µg/L. Nineteen aroma compounds, including β-phenylethanol, 2,3,5,6-tetramethylpyrazine, dimethyl trisulfide, and 2-methyl-3-(methyldisulfanyl)furan, had RDTs lower than their orthonasal detection thresholds. Power function curves were used to establish correlations between RDTs and partition coefficients for five esters and four pyrazines (R2  = 0.9575, 0.9969, respectively). Twenty-nine aroma compounds had retronasal odor activity values >1 in a soy sauce aroma type Baijiu. Additionally, time-intensity (TI) results suggested that hexanoic acid, ethyl hexanoate, isoamyl acetate, 3-methyl-butanal, and nonanal contributed to a "burst-aroma" of Baijiu. Conversely, TI results attributed the "after-odor" of Baijiu to dimethyl trisulfide, methional, 2,3,5,6-tetramethylpyrazine, β-phenylethanol, and other compounds. PRACTICAL APPLICATION: This manuscript provides comprehensive information on the retronasal sensory characteristics of aroma compounds in Baijiu. The results obtained may help understand the contribution of aroma compounds to retronasal aroma perception during Baijiu tasting and give helpful information to the Baijiu industry regarding quality control.

Application of toasted vine-shoot chips and ultrasound treatment in the ageing of Primitivo wine

Ageing wine in barrels is an historical practice used to improve the aromatic complexity of wine, but due to the high cost and the long ageing period, alternative approaches have been developed, such as the use of wood chips and ultrasound treatment. The present paper reports the results of an investigation performed on wine (cv. Primitivo). Three treatments were investigated: a) control wine untreated; b) wine with toasted vine-shoot chips (10 g/L); c) wine with toasted vine-shoot chips (10 g/L) and treated by ultrasound. Wines were analysed after 7, 14, 21, and 28 days. The application of ultrasound combined with vine-shoot chips promoted tannin evolution, thereby accelerating the ageing process of wine. The chips addition decreased the total anthocyanins content and increased the stilbenes (trans-resveratrol and trans-piceid) and wood-related aromas (i.e., furfural, 5-methylfurfural) concentration. Finally, wines added with chips were richer in woody, vanilla, oak, and chocolate notes and more preferred by the tasters.

Charentaise distillation of cognac. Part I: Behavior of aroma compounds

The Charentaise distillation plays an essential role in designing cognac aroma by extracting and selectively concentrating aroma compounds from the wine along with ethanol, in addition to promoting compound formation or degradation through different chemical reactions. This traditional mode of distillation still relies heavily on empirical knowledge and the impact of its different parameters on the composition of cognac is not fully elucidated. In this context, this study aimed to broaden the current knowledge on the behavior of aroma compounds throughout the two steps of the Charentaise distillation and to investigate the formation of aroma compounds during the operation, an aspect which is seldom considered. The concentration profiles of 62 aroma compounds were represented over time for a wine and a brouillis distillation in usual scale (25 hL) with recycling. A classification system was then proposed to group compounds based on their volatilities at different ethanol concentrations in the boiling liquid, their concentration profiles and their chemical properties. This could help identify how chemical characteristics of aroma compounds affect their volatilities in hydroalcoholic media during distillation. In addition, several compounds appear to be formed during distillation, most of which are terpenes, norisoprenoids and aldehydes. Finally, to highlight the importance of different compounds to the aroma of freshly distilled cognac, their odor activity values (OAV) in the heart fraction were estimated, revealing isobutanol and (E)-ß-damascenone to be the most odorant compounds. These results provided additional elements of understanding for different aspects of the Charentaise distillation for the production of cognac, several of which can be transposed, at least in part, to different modes of distillation pertaining to other distilled beverages.

The role of saliva in taste and food intake

Saliva is well-described in oral food processing, but its role in taste responsiveness remains understudied. Taste stimuli must dissolve in saliva to reach their receptor targets. This allows the constituents of saliva the opportunity to interact with taste stimuli and their receptors at the most fundamental level. Yet, despite years of correlational data suggesting a role for salivary proteins in food preference, there were few experimental models to test the role of salivary proteins in taste-driven behaviors. Here we review our experimental contributions to the hypothesis that salivary proteins can alter taste function. We have developed a rodent model to test how diet alters salivary protein expression, and how salivary proteins alter diet acceptance and taste. We have found that salivary protein expression is modified by diet, and these diet-induced proteins can, in turn, increase the acceptance of a bitter diet. The change in acceptance is in part mediated by a change in taste signaling. Critically, we have documented increased detection threshold, decreased taste nerve signaling, and decreased oromotor responding to quinine when animals have increases in a subset of salivary proteins compared to control conditions.

Recent trends in aroma release and perception during food oral processing: A review

The dynamic and complex peculiarities of the oral environment present several challenges for controlling the aroma release during food consumption. They also pose higher requirements for designing food with better sensory quality. This requires a comprehensive understanding of the basic rules of aroma transmission and aroma perception during food oral processing and its behind mechanism. This review summarized the latest developments in aroma release from food to retronasal cavity, aroma release and delivery influencing factors, aroma perception mechanisms. The individual variance is the most important factor affecting aroma release and perception. Therefore, the intelligent chewing simulator is the key to establish a standard analytical method. The key odorants perceived from the retronasal cavity should be given more attention during food oral processing. Identification of the olfactory receptor activated by specific odorants and its binding mechanisms are still the bottleneck. Electrophysiology and image technology are the new noninvasive technologies in elucidating the brain signals among multisensory, which can fill the gap between aroma perception and other senses. Moreover, it is necessary to develop a new approach to integrate the relationship among aroma binding parameters, aroma concentration, aroma attributes and cross-modal reactions to make the aroma prediction model more accurate.

Cluster Thinning Improves Aroma Complexity of White Maraština (Vitis vinifera L.) Wines Compared to Defoliation under Mediterranean Climate

Defoliation and cluster thinning are useful canopy management techniques to modulate grapevine carbon distribution and microclimate. Both techniques are directed to achieve the proper balance between fruit and foliage, and to maximize production of well-ripened fruits and quality wines. We performed five canopy treatments on Maraština grapevine grown at a commercial vineyard in the Vrgorac Valley region of Croatia: three different times of basal defoliation, cluster thinning at the veraison, and an untreated control. The effects of the canopy changes on the chemical composition of grapes and wines were studied. The treatments had variable impacts on yield components and basic wine composition. Volatile aroma compounds in produced wines were analyzed using gas chromatography–mass spectrometry coupled with a mass-selective detector. The concentrations of 70 of the 96 individual volatile compounds were significantly influenced by the canopy technique used. The concentrations of 58 of these compounds were different according the timing of defoliation. Cluster thinning at an intensity of 35% produced wines with more terpenes, esters, higher alcohols, other alcohols, volatile phenolic compounds, lactones, and other compounds than other treatments. Among terpenes, cluster thinning increased terpinen-4-ol, linalool, trans-β-farnesen, and geraniol. Odor activity value analysis revealed 16 volatile compounds that contributed to the aroma of cluster-thinned wines.

Effects of oenological tannins on aroma release and perception of oxidized and non-oxidized red wine: A dynamic real-time in-vivo study coupling sensory evaluation and analytical chemistry

Addition of oenological tannins claims to have a positive impact on wine stability, protection from oxidation and likely sensory persistence. However, their role on red wine aroma during oxidation is controversial. The present study aims at investigating the effect of addition of oenological tannins on wine flavour (mainly aroma) before and after air exposure. Temporal Dominance of Sensations, a dynamic sensory evaluation, was coupled with a dynamic chemical measurement (nosespace analysis) using a Proton-Transfer-Reaction Mass-Spectrometer connected to the nasal cavity of 17 assessors. Results showed that the oxidation of a non-oaked Pinot Noir red wine decreases the fruity aroma dominance and increases the maderised and prune one. A contextual decrease of the fruity ethyl decanoate and increase of oxidative Strecker aldehydes are observed. Ellagitannins but not proanthocyanidins preserved perception of fruitiness and prevented increase of maderised notes. Moreover, ellagitannins increase the aroma persistence mainly in the non-oxidized wine.

Influence of tannins, human saliva, and the interaction between them on volatility of aroma compounds in a model wine

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.

Oral Release Behavior of Wine Aroma Compounds by Using In-Mouth Headspace Sorptive Extraction (HSSE) Method

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.

Interactions between Polyphenols and Volatile Compounds in Wine: A Literature Review on Physicochemical and Sensory Insights

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.

Aroma release during wine consumption: Factors and analytical approaches

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.

Exploring Olfactory-Oral Cross-Modal Interactions through Sensory and Chemical Characteristics of Italian Red Wines

This work aimed at investigating red wine olfactory–oral cross-modal interactions, and at testing their impact on the correlations between sensory and chemical variables. Seventy-four Italian red whole wines (WWs) from 10 varieties, and corresponding deodorized wines (DWs), were evaluated by sensory descriptive assessment. Total phenols, proanthocyanidins, ethanol, reducing sugars, pH, titratable and volatile acidity were determined. PCA results highlighted different sensory features of the 10 wine types. ANOVAs (p < 0.05) showed that olfactory cues might play modulation effects on the perception of in-mouth sensations with 7 (harsh, unripe, dynamic, complex, surface smoothness, sweet, and bitter) out of 10 oral descriptors significantly affected by odours. Three weak but significant positive correlations (Pearson, p < 0.0001) were statistically found and supported in a cognitive dimension: spicy and complex; dehydrated fruits and drying; vegetal and unripe. In the absence of volatiles, correlation coefficients between sensory and chemical parameters mostly increased. Proanthocyanidins correlated well with drying and dynamic astringency, showing highest coefficients (r > 0.7) in absence of olfactory–oral interactions. Unripe astringency did not correlate with polyphenols supporting the idea that this sub-quality is a multisensory feeling greatly impacted by odorants. Results support the significance of cross-modal interactions during red wine tasting, confirming previous findings and adding new insights on astringency sub-qualities and their predictive parameters.

Impact of closure type and storage temperature on chemical and sensory composition of Malbec wines (Mendoza, Argentina) during aging in bottle

Malbec is the flagship variety of Argentina mainly due to its high oenological value and plasticity to obtain different wine styles. During bottled aging, the chemical and organoleptic composition of wines is subject to changes depending on the aging conditions (closure, oxygen level, temperature, time). However, the combined effect of these factors on chemical composition and organoleptic characteristics of Malbec wines has not been studied yet. Wines were bottled with screw cap and natural cork and were kept in chambers at 15 °C and 25 °C for 2 years. Sampling was performed at 2, 4, 6, 9, 12, 15, 18, 21 and 24 months. Concentrations of free sulfur dioxide, dissolved oxygen, anthocyanins, tannins, esters, volatile phenols, organic acids, and color saturation decreased during the storage process. While, the formation of polymeric pigments, the color attributes (lightness and hue) and the levels of alcohols, norisoprenoids, furanoids and terpenoids increased. At 24 months, Malbec wines were organoleptically different. Wines kept at 15 °C were associated with high sensory perceptions in color intensity and violet tint, those presented a positive correlation with free sulfur dioxide, tannins, and anthocyanins levels. On the contrary, wines aged at 25 °C were linked with high sensory perceptions of dried vegetative and dried fruit aromas. These descriptors were positively correlated with norisoprenoids, furanoids, and terpenoids. In general, the chemical composition and organoleptic attributes of bottled Malbec wines (Mendoza, Argentina) were stable respect closure type employed, but highly sensitive to the combined effect of time and storage temperature. This finding is key to making decisions about the wine style searched, and costs (e.g. refrigeration) involved in the conservation period until consumption.