A Study of the Physico-chemical Behavior of Diacetyl in Hydroalcoholic Solution With and Without Added Catechin and Wood Extract

The interactions of diacetyl and ethanol in model solutions were studied in order to improve understanding of the changes in flavor perception that occur during both alcoholic beverage processing and consumption. A gradual reduction was demonstrated in the activity and partition coefficients of diacetyl as the ethanol concentration in aqueous solutions increased. From a sensory point of view, this fact would be expected to cause an increase in the diacetyl sensory thresholds. The expected diacetyl sensory thresholds were calculated based on experimental determination of the diacetyl vapor pressure in ethanol-water solutions at different ethanol concentrations. These sensory thresholds were not measured but merely obtained by theoretical interpolations. No significant variations in the activity coefficients of diacetyl were observed in the presence of catechin. Conversely, the dissolution of wood extract at 40% ethanol caused a significant decrease in diacetyl vapor pressure. The addition of catechin and wood extract to 40% ethanol-water solution contributed to the interactions of ethanol and water measured by DSC analysis.     

CONTRIBUTION OF GLYCEROL, ETHANOL AND SUGAR TO THE PERCEPTION OF VISCOSITY AND DENSITY ELICITED BY MODEL WHITE WINES

The contribution of glycerol, ethanol and sugar to the perception of viscosity and density of model wine (MW) solutions was examined. In study 1, the effects of individual components on perceived viscosity (PV) and perceived density (PD) were studied using 5, 20 or 50 g/L glycerol; 3, 7 or 15% v/v ethanol and 0, 80, 150 or 250 g/L sugar concentrations. In study 2, model ice wine mixtures of 8, 10 or 12% ethanol and 150, 250 or 300 g/L sugar were assessed for PV and PD. The physical viscosity and density of the MWs were also measured in both studies. Across the range of concentrations investigated, sugar influences the perception of viscosity and density the most, ethanol has a moderate effect and the contribution of glycerol is nominal. In model ice wine solutions, PV and PD increased with sugar concentration, but were minimally affected by changes in ethanol concentration. The PV elicited by the model ice wine solutions was well described by a linear model using physical viscosity as the independent variable (r: 0.907). This information may be useful for predicting the sensory properties of the ice wine for quality control purposes.     

The olfactory masking effect of ethylphenols: Characterization and elucidation of its origin

To date, most of the sensory studies concerning off-flavors focus on their detection or rejection thresholds. However, both supra and sub-threshold concentrations of off-flavor components may change the perception of odorous mixtures. In this context, the aim of this study was to determine the impact of infra- and supra-threshold concentrations of a wine defect, “Bretty” character (ethylphenols), on the wine fruity note. Techniques used included sensory analysis (odor profiling), psychophysical tests (threshold measurements), and chemical analyses (GCMS). The sensory test panels consisted of wine experts. The results showed that both sub- and supraliminal concentrations of off-flavors could interfere with the perception of fruity notes. In addition, the findings revealed that this wine defect not only changes the hedonic valence of the perception, but also has a masking effect on fruity notes, even at subliminal concentrations. The final experiment demonstrated that the interaction between the perception of ethylphenols and ethyl heptanoate takes place at a central locus in the olfactory system.     

Crossmodal correspondence between color,shapes, and wine odors

Crossmodal correspondence is of scientific and commercial interest in regard to the packaging of food and beverages. Research has shown that colors and shapes can be associated with certain aromas, but these interactions have been less extensively studied with authentic visual stimuli (i.e., packaging), or with complex food odors in a matrix. This study investigated odor-color-shape crossmodal interactions with complex odor stimuli (wine odors) and wine labels. The present research used projective mapping with 3D shapes and colors, along with a wine label matching study, to test whether chardonnay odors of different character (buttery, citrus, floral, smoky, and vegetable) were associated with certain colors and shapes. In the projective mapping experiment, most chardonnay odors were grouped similarly; however, the vegetable-forward wine was more associated with sharper shapes. In the label experiment, yellow labels tended to be better matched with all odors, except the vegetable-forward wine, which was matched equally to all colors. These findings indicate that, regardless of odor character, chardonnay is mostly associated with a yellow colored label. Interestingly, results also indicated that not all correspondences aligned with the most common color association of an odor character’s (i.e., vegetative was not strictly associated with green, nor smoky with brown, etc.). Significant correlations were found between stimuli liking and matching scores, speaking to the role of hedonics in correspondences. Overall, the present research demonstrates evidence for odor-color-shape correspondences in complex odors and realistic visual stimuli, but not as strongly as in controlled environments and simplistic stimuli.     

乙醇国标检测方法间差异及适用范围的讨论

以10个品种的30个酒样为研究对象,分别采用国标GB 5009.225—2016《食品安全国家标准酒中乙醇浓度的测定》中的第一法、第二法和第四法对乙醇浓度进行检测,通过检测结果比较方法间差异及探讨方法的适用范围。结果表明,不同方法间乙醇测定结果差异不大,差值均在国标方法规定的误差允许范围内,无方法间差异,且对于第四法除国标规定的啤酒、威士忌、白兰地和伏特加外,白酒、葡萄酒、黄酒、配制酒、朗姆酒和酒精的乙醇检测同样适用。     

Perception of wine fruity and woody notes: influence of peri-threshold odorants

In order to test the hypothesis that woody odorants at sub- and peri-threshold concentrations could modify the olfactory perception of supra-threshold fruity notes in wine, three binary mixtures of fruity and woody odorants were studied. In these mixtures, a single supra-threshold concentration level, close to the one usually found in wine, was used for the fruity note whereas three peri-threshold concentration levels of the woody note were tested. The ability to discriminate odour stimuli on the basis of the presence or absence of the woody odorants in the mixtures was investigated with a triangular test.For the three binary mixtures the results showed that subjects were able to differentiate between samples containing a woody odorant at all concentration levels from samples without a woody odorant. These findings confirmed the impact of sub- and peri-threshold components on the olfactory perception of odour mixtures, especially in the case of wine woody odorants.     

Influence of light exposure, ethanol and copper(II) on the formation of a precursor for xanthylium cations from tartaric acid

The production of xanthylium cation pigments was greatly increased when an aged, tartaric acid buffered, 12% (v/v) aqueous ethanol solution was used in a model white wine system. This suggested the formation of a precursor to the pigments during the ageing of the tartaric acid solution. On examining factors responsible for the generation of tartaric acid oxidation products in wine-like solutions it was observed that on exposure of samples to sunlight, glyoxylic acid, a known precursor to xanthylium cations, was produced. The production of glyoxylic acid was achieved in both the absence and presence of ethanol and copper(II). Hydrogen peroxide was also detected in these solutions. The results were consistent with the presence of glyoxylic acid in the aged tartaric acid buffered, 12% (v/v) aqueous ethanol solution that had frequent aeration and periodic exposure to sunlight throughout its storage. Studies on the role of hydrogen peroxide in the production of glyoxylic acid were also investigated. On the addition of hydrogen peroxide to tartaric acid solutions, with heating at 45°C in darkness, glyoxylic acid was only determined in solutions without ethanol.     

Effect of polyphenols on the perception of key aroma compounds from Sauvignon Blanc wine

Background and Aims:  Sensory wine research has mainly focused on the role of volatile compounds and their contribution to the aroma profile. Wines also contain polyphenolic compounds, which are not volatile. This research begins to investigate the interactions of volatile and non-volatile wine compounds and the consequential effects on sensory perception of aroma.
Methods and Results:  Trained panellists of this study measured the perception of four aroma compounds (isobutyl methoxypyrazine, 3-mercaptohexanol, 3-mercaptohexanol acetate and ethyl decanoate) in wine. Panellists assessed the four compounds in combinations with three polyphenols (catechin, caffeic acid and quercetin) commonly found in white wine. The perception of isobutyl methoxypyrazine, 3-mercaptohexanol and ethyl decanoate was largely suppressed by the added polyphenols, while the perception of 3-mercaptohexanol was accentuated with the addition of caffeic acid. Of the three polyphenols, only catechin had a slight effect of accentuating the mercaptohexanol acetate perception.
Conclusions:  Results showed each polyphenol had a unique effect when blended with a specific aroma compound, either suppressing, accentuating or showing little effect on the perception of the aroma compounds.
Significance of the Study:  Understanding these interactions can assist winemakers in managing polyphenol levels to optimize selected volatile compounds to achieve desirable aroma profiles.     

The role of congruency in taste–odor interactions

The present study investigated the role that congruency between tastes and odors plays in two types of taste–odor interactions: retronasal odor enhancement by taste and retronasal odor referral to the mouth. In the first experiment, subjects rated (1) the intensities of sweetness, sourness, bitterness, and specific odor of aqueous samples of 3 tastants (sucrose, citric acid, caffeine) and 2 odorants (citral, coffee odor), both alone and in taste–odor mixtures, and (2) the degree of congruency of all possible taste–odor pairs. The results showed that only sucrose significantly enhanced the perceived intensities of citrus and coffee odors (Tukey’s test, p < 0.05), while citric acid and caffeine failed to enhance or even suppressed the odors. In the second experiment, the returning subjects were asked (1) to report the perceived locations of the odors after inhaling 3 odorants (citral, “sweet” and “bitter” coffee odors) through the mouth alone or in the presence of either water or various tastes in the mouth, and (2) to rate the degree of congruency between tastes and odors. The data showed that a highly congruent taste or taste mixture significantly increased localization of odors to the mouth (χ², p < 0.05). These findings suggest that taste–odor congruency is a necessary but not sufficient condition for retronasal odor enhancement. In contrast, taste–odor congruency is a critical component for retronasal odor referral, and the degree of congruency modulates the degree of odor referral to the mouth. The results and implications of the study findings are discussed in terms of cognitive and perceptual factors of flavor perception.     

Production technologies for reduced alcoholic wines

The production and sale of alcohol-reduced wines, and the lowering of ethanol concentration in wines with alcohol levels greater than acceptable for a specific wine style, poses a number of technical and marketing challenges. Several engineering solutions and wine production strategies that focus upon pre- or postfermentation technologies have been described and patented for production of wines with lower ethanol concentrations than would naturally arise through normal fermentation and wine production techniques. However, consumer perception and acceptance of the sensory quality of wines manufactured by techniques that utilize thermal distillation for alcohol removal is generally unfavorable. This negative perception from consumers has focused attention on nonthermal production processes and the development or selection of specific yeast strains with downregulated or modified gene expression for alcohol production. The information presented in this review will allow winemakers to assess the relative technical merits of each of the technologies described and make decisions regarding implementation of novel winemaking techniques for reducing ethanol concentration in wine.     

Interactions of phenolic and volatile compounds with yeast lees,commercial yeast derivatives and non toasted chips in model solutions and young red wines

Ageing of wines on lees, the use of commercial yeast derivative products and the addition of oak chips to wine permit the release of different compounds such as mannoproteins and polysaccharides into wines during yeast autolysis. These compounds released can interact with phenolic compounds and/or aromatic compounds, also modifying wine sensory perception. For that reason, the aim of this work was to evaluate the interaction of phenolic and volatile compounds of wines with yeast lees, non-toasted oak wood chips and different commercial yeast derivative preparations in model wine solutions and in a real red wine. The results found in this study have shown that most of the phenolic and volatile compounds studied are adsorbed by wood and bound by lees in model wine solutions. However, in the model wines in general, the commercial yeast derivative products studied only interacted with the volatile compounds but not with the phenolic compounds. The adsorption of the phenolic compounds occurred in the first 15 days of treatment, remaining constant for 2 months; however, in the case of volatile compounds, these compounds initially displayed a retention effect, but after 30–60 days, the release of the previously bound compounds was instigated. The adsorption effect on the phenolic and volatile compounds in the model wine solution was not always the same as in the red wine studied, which highlights the important presence of other wine compounds in these interactions.     

Effects of ethanol,tannin and fructose on the headspace concentration and potential sensory significance of odorants in a model wine

The effects of ethanol (8, 10, 12, 14, and 16% v/v), tannin (500, 1000, and 1500 mg/L) and fructose (200 and 2000 mg/L) concentrations on the headspace of eight selected odorants were investigated using headspace solid phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC–MS). Analysis of variance results (ANOVA) showed significant interaction effects for the majority of odorants (P < 0.05). In general, higher tannin concentration enhanced the release of odorants while fructose induced a retention effect, both of which were largely dependent upon ethanol concentration. The net magnitude effect was a substantial reduction in the headspace concentration of odorants with the dominant contribution from ethanol concentration. The percent reduction in extracted odorant was more pronounced on larger molecular weight compounds. Further multivariate analysis discriminated model wines with different ethanol concentrations and, to a lesser extent, separated model wines with different fructose and tannin concentrations. Subsequent gas chromatography–olfactometry (GC–O) analysis revealed differences in the estimated odor thresholds of odorants in the model wines. Threshold values increased between 2 and 10,000-fold for 2-methoxyphenol and eugenol, respectively, at higher ethanol, tannin and fructose concentrations. Consequently, odor unit values (OUV) of odorants decreased indicating a reduction in the potential contribution of the odorants to the aroma of model wine. These results highlighted the significant impact that wine matrix interactions can have on wine aroma quality.     

Effect of wine addition on microbiological characteristics,volatile molecule profiles and biogenic amine contents in fermented sausages

The aim was to evaluate the effect of wine addition during manufacturing of dry fermented sausages, in terms of safety aspects (biogenic amine accumulation), aroma profile and sensory characteristics. Three batches of salami were produced: without wine addition and with 7.5% or 15% (v/w) of white wine. The fermented sausages showed characteristics that can increase product diversification. Some of the sensory features (i.e. increased salty perception) can represent an important strategy because of the trend to reduce salt intake for health reasons. The presence of wine immediately reduced the pH and is a source of ethanol, which can have an inhibitory effect against undesirable microflora. The microbiological results observed regarding Enterobacteriaceae and enterococci were encouraging. The addition of wine did not negatively affect the ripening time or increase the presence of biogenic amines. The samples containing wine showed reduced concentrations of putrescine.     

How trigeminal,taste and aroma perceptions are affected in mint-flavored carbonated beverages

The integration of olfactory, taste and trigeminal perceptions must be taken into account to better understand the perception of beverages. To do this, seven beverages were formulated to investigate the role of ingredients on trigeminal perception. All mutual interactions between olfactory, gustatory and trigeminal perceptions were studied. Instrumental measurements and sensory evaluation were used to elucidate both physicochemical and sensory interactions. Sensory profiling was conducted according to monadic product presentation, and in vivo aroma release was assessed in the nasal cavities of subjects during beverage consumption.This study further revealed the influence of trigeminal perception on taste and aroma in complex beverages. The addition of CO₂ in beverages induced a decrease in sweetness perception, an increase in sourness perception and an enhancement of aroma perception. Physicochemical and/or physical mechanisms (pH, aroma stripping effect) were assumed to be at the origin of these gustatory and olfactory interactions. Furthermore, the addition of mint flavoring enhanced tingling and freshness perceptions, highlighting perceptual interactions. The presence of sugar was shown to decrease the freshness perception but not the tingling perception.     

Precipitation of salivary proteins after the interaction with wine: the effect of ethanol, pH, fructose, and mannoproteins

Astringency is a complex sensation mainly caused by the precipitation of salivary proteins with polyphenols. In wine it can be enhanced or reduced depending on the composition of the medium. In order to investigate the effect of ethanol, tartaric acid, fructose, and commercial mannoproteins (MPs) addition on the precipitation of salivary proteins, the saliva precipitation index (SPI) was determined by means of the sodium dodecyl sulphate polyacrylamide gel electrophoresis of human saliva after the reaction with Merlot wines and model solutions. Gelatin index, ethanol index, and Folin-Ciocalteu index were also determined. As resulted by Pearson's correlation, data on SPI were well correlated with the sensory analysis performed on the same samples. In a second experiment, increasing the ethanol (11%-13%-17%), MPs (0-2-8 g/L), fructose (0-2-6 g/L) level, and pH values (2.9-3.0-3.6), a decrease in the precipitation of salivary proteins was observed. A difference in the SPI between model solution and red wine stated that an influence of wine matrix on the precipitation of salivary proteins occurred. PRACTICAL APPLICATION: Results provide interesting suggestions for enologists, which could modulate the astringency of red wine by: (i) leaving some residual reducing sugars (such as fructose) in red wine during winemaking of grapes rich in tannins; (ii) avoiding the lowering of pH; (iii) adding commercial mannoproteins or promoting a "sur lie" aging; and (iv) harvesting grapes at high technological maturity in order to obtain wines with a satisfactory alcoholic content when possible.     

气味与滋味间相互作用对食品风味感知影响研究进展

食品风味是影响消费者购买欲的重要因素,而风味感知的形成受嗅觉、味觉等多种感官的共同影响,利用气味与滋味间感知交互作用改善食品风味已成为最受关注的食品风味调控新方向之一。基于此,本文首先从神经生物学角度分析嗅觉与味觉间跨模态感知交互作用的主要形成通路及机制,然后从静态感官分析和动态感官分析两个方面总结跨模态感知交互作用的主要研究方法,最后结合相关文献案例分别综述气味物质对味觉感知（甜、咸、苦、鲜和酸）以及滋味物质对嗅觉感知的影响,旨在为食品加工过程风味品质的调控提供新思路。     

NITROSAMINES IN ALCOHOLIC BEVERAGES

A limited survey was carried out to determine the nitrosamine content of several varieties of alcoholic beverages (beer and ale, whiskey, wine, cider, etc.) sold in Canada. Of 22 samples of different beers and ales analyzed all but one contained traces of dimethylnitrosamine; the overall mean level found was 1.5 ppb. Only one Canadian rye and one Scotch whiskey out of a total of 13 samples contained traces of either dimethylnitrosamine or diethylnitrosamine. All the 8 wines and 7 cider samples were negative.     

Impact of matrix variables and expertise of panelists on sensory thresholds of 1,1,6-trimethyl-1,2-dihydronaphthalene known as petrol off-flavor compound in Riesling wines

1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN) is known to elicit the perception of “petrol off-flavor” in wine, most prominent in the variety Riesling. This study was focused on the impact of matrix variables such as ethanol and carbonation on the odor detection threshold of TDN. Increasing carbonation nearly doubled the detection threshold in water, however, this effect could not be observed in alcoholic matrices. Ethanol enhanced detection thresholds presumably due to diminished volatilization, which was only partially supported by measurement of partition coefficients using GC–MS. Overall, the impact of matrix changes was small ranging from 1.1 µg/L in still water to 4.0 µg/L in Riesling sparkling wine. Consumer detection threshold of 14.7 µg/L TDN determined with 156 consumers exceeded the threshold of the trained panel by a factor of five and varied by consumers’ age and gender. Rejecting a Riesling wine due to its petrol off-flavor, 60 µg/L TDN were required in a young and 91 µg/L in an eight-year-old Riesling wine. Based on analytical data for more than 250 commercial Riesling wines, geographic origin and to a smaller extent wine age contributed to large differences in TDN concentrations. About half of the investigated wines exceeded the detection threshold of the trained panel, whereas consumers would have noticed TDN in only less than 15% of the Riesling wines. Merely 3% of the wines actually exceeded the consumer rejection threshold of TDN. For both, detection and consumer rejection thresholds, the applied methodology contributed considerably to the final values, which is discussed critically.     

Impact of chemical profile on sensory evaluation of tropical red wines

This study evaluated the correlation between the chemical composition of red wines and the sensory perception of the products. The visual, gustatory and flavour attributes of eight samples of tropical red wines were characterised by semi-trained panellists using the check-all-that-apply methodology. Titratable and volatile acidity, pH, contents of ethanol, total polyphenols and anthocyanins, and the chromatic parameters of the red wine samples were determined. The analysis of the correlations between visual attributes and sensory perception indicated that the evaluation of the wine colour attributes can predict other sensory characteristics related to aromas and flavours. This enabled the wine tasters to distinguish subtle variations in the visual attributes of the product. The results of this study indicated that panellists who underwent short-term training can sensorially perceive the influence of physicochemical variables on wine quality. Additionally, the correlation analysis enabled the identification of production adjustments and the understanding of the consumer perception of a complex product.