Understanding flavour perception of espresso coffee by the combination of a dynamic sensory method and in-vivo nosespace analysis

Influence of Chewing Rate and Food Composition on in Vivo Aroma Release and Perception of Composite Foods

This study investigated the effects of chewing rate and food composition on in vivo aroma release and perception of composite foods. Bread or sponge cake paired with varying sugar content and viscosity strawberry jams, spiked with citral and limonene, were examined. In-nose release was characterized using Proton-Transfer-Reaction-Time-of-Flight-Mass-Spectrometry (PTR-ToF-MS). Simultaneously, Time-Intensity (TI) profiling assessed citrus aroma perception (n = 8, triplicate) while fast and slow chewing protocols were applied (fast: 1.33 chews/s; slow 0.66 chews/s; each for 25 s). Chewing rate did not significantly impact the area under the curve and maximum intensity of in vivo citral and limonene release and citrus aroma perception. Faster chewing rates significantly decreased the time to reach maximum intensity of aroma release (p < 0.05) and citrus aroma perception (p < 0.001). Faster chewing rates probably accelerated structural breakdown, inducing an earlier aroma release and perception without affecting aroma intensity. Adding carriers to jams significantly (p < 0.05) increased aroma release, while perceived citrus aroma intensity significantly (p < 0.05) decreased regardless of chewing rate. In conclusion, chewing rate affects the temporality of in vivo aroma release and perception without affecting its intensity, and carrier addition increases in vivo aroma release while diminishing aroma perception.

Multi-attribute temporal descriptive methods in sensory analysis applied in food science: A systematic scoping review

Among descriptive sensory evaluation methods, temporal methods have a wide audience in food science because they make it possible to follow perception as close as possible to the moment when sensations are perceived. The aim of this work was to describe 30 years of research involving temporal methods by mapping the scientific literature using a systematic scoping review. Thus, 363 research articles found from a search in Scopus and Web of Science from 1991 to 2022 were included. The extracted data included information on the implementation of studies referring to the use of temporal methods (details related to subjects, products, descriptors, research design, data analysis, etc.), reasons why they were used and the conclusions they allowed to be drawn. Metadata analysis and critical appraisal were also carried out. A quantitative and qualitative synthesis of the results allowed the identification of trends in the way in which the methods were developed, refined, and disseminated. Overall, a large heterogeneity was noted in the way in which the temporal measurements were carried out and the results presented. Some critical research gaps in establishing the validity and reliability of temporal methods have also been identified. They were mostly related to the details of implementation of the methods (e.g., almost no justification for the number of consumers included in the studies, absence of report on panel repeatability) and data analysis (e.g., prevalence of use of exploratory data analysis, only 20% of studies using confirmatory analyses considering the dynamic nature of the data). These results suggest the need for general guidelines on how to implement the method, analyze and interpret data, and report the results. Thus, a template and checklist for reporting data and results were proposed to help increase the quality of future research.

Dynamic Instrumental and Sensory Methods Used to Link Aroma Release and Aroma Perception: A Review

Perception of flavor is a dynamic process during which the concentration of aroma molecules at the olfactory epithelium varies with time as they are released progressively from the food in the mouth during consumption. The release kinetics depends on the food matrix itself but also on food oral processing, such as mastication behavior and food bolus formation with saliva, for which huge inter-individual variations exist due to physiological differences. Sensory methods such as time intensity (TI) or the more-recent methods temporal dominance of sensations (TDS) and temporal check-all-that-apply (TCATA) are used to account for the dynamic and time-related aspects of flavor perception. Direct injection mass spectrometry (DIMS) techniques that measure in real time aroma compounds directly in the nose (nosespace), aimed at obtaining data that reflect the pattern of aroma release in real time during food consumption and supposed to be representative of perception, have been developed over the last 25 years. Examples obtained with MS operated in chemical ionization mode at atmospheric or sub-atmospheric pressure (atmospheric pressure chemical ionization APCI or proton-transfer reaction PTR) are given, with emphases on studies conducted with simultaneous dynamic sensory evaluation. Inter-individual variations in terms of aroma release and their relevance for understanding flavor perception are discussed as well as the evidenced cross-modal interactions.

In vivo aroma release and perception of composite foods using nose space PTR–ToF–MS analysis with Temporal-Check-All-That-Apply

In vivo aroma release and perception of complex food matrices have been underexplored. The aims of this study were to investigate the effects of (i) fat and sugar content of chocolate-hazelnut spreads on in vivo aroma release and perception and (ii) carrier addition (bread, wafer) on in vivo aroma release and perception of chocolate-hazelnut spread using dynamic nose space analysis (PTR-ToF-MS) and dynamic sensory analysis (TCATA). Carriers were combined with spreads varying in fat and sugar content and were spiked with five volatile organic compounds (benzaldehyde, filbertone, 2-methylpyrazine, delta-dodecalactone, isovaleraldehyde). TCATA profiles from a consumer panel without in vivo nose space analysis (n = 72) and a trained panel performing in vivo nose space analysis (n = 8, triplicate) were compared. TCATA profiles of the spread-carrier combinations obtained by both panels showed similarly that attributes related to the carriers were perceived at the beginning of consumption, whereas attributes related to the spreads were perceived after swallowing. Significant (p < 0.05) and small differences were observed for the attributes cocoa, creamy, milky, sticky and toffee between both panels. In the evaluated reformulation range, fat and sugar content of chocolate-hazelnut spreads had only a limited effect on in vivo aroma release and perception. In contrast, addition of carriers strongly affected in vivo aroma release and perception for all target molecules. The addition of carriers to spreads generally increased aroma release (duration and intensity of aroma release) and decreased aroma perception. The addition of carriers generally reduced the time to reach maximum intensity compared to when spreads were eaten alone for the five volatile organic compounds while perception decreased. We conclude that the strong effect of carrier addition on in vivo aroma release and perception of chocolate-hazelnut spreads highlights the importance of investigating toppings/spreads accompanied with carriers rather than in isolation.

Effect of sweeteners and carbonation on aroma partitioning and release in beverage systems

The effect of monosaccharides (glucose, fructose and galactose) and disaccharides (sucrose and lactose) at 10, 20 and 30 % w/v on the in-vitro aroma partitioning of C₄ - C₁₀ aldehydes and ethyl esters, as well as limonene (concentration of aroma compounds at 1 μg mL^-1), was studied using atmospheric pressure chemical ionisation-mass spectrometry. An increase in sugar concentration from 0 to 30 % w/v resulted in a significant increase in partitioning under static headspace conditions for the majority of the compounds (p < 0.05), an effect generally not observed when 10 % w/v sucrose was substituted with low-calorie sweeteners (p > 0.05). The complexity of the system was increased to model a soft drink design - comprising water, sucrose (10, 20 and 30 % w/v), acid (0.15 % w/v), carbonation (∼7.2 g/L CO₂) and aroma compounds representative of an apple style flavouring, namely ethyl butanoate and hexanal (10 μg mL^-1 each). Although the addition of sucrose had no significant in-vivo effect, carbonation significantly decreased breath-by-breath (in-vivo) aroma delivery (p < 0.05). To understand the physical mechanisms behind aroma release from the beverage matrix, the effect of sucrose on the kinetics of the matrix components was explored. An increase in sucrose concentration from 0 to 30 % w/v resulted in a significant decrease in water activity (p < 0.05), which accounted for the significantly slower rate of self-diffusion of aroma compounds (p < 0.05), measured using diffusion-ordered spectroscopy-nuclear magnetic resonance spectroscopy. No significant effect of sucrose on carbon dioxide volume flux was found (p > 0.05).

The Impact of Vanilla and Lemon Aromas on Sensory Perception in Plant-Based Yogurts Measured with Static and Dynamic Methods

The application of cross-modal interaction is a potential strategy to tackle the challenges related to poor sensory properties, such as thin mouthfeel, in plant-based yogurts. Thus, we aim to study the influence of aroma compounds possibly congruent with sweetness on the perceived sensory profile. Descriptive analysis and temporal dominance of sensations (n = 10 × 4) with a trained panel were conducted with and without a nose clip. One unflavored sample and samples flavored with either lemon or vanilla aromas were included (vanilla; 0.05%; 0.1%; lemon: 0.025%; 0.05%). Odor intensity, thick, sticky, and melting sensation, sweetness, and grain-like flavor were evaluated on an unstructured 10-cm line scale with anchors and reference samples. The results demonstrate how vanilla and lemon aromas suppressed grain-like flavor and enhanced odor intensity and sweetness. The following order was detected among samples in perceived sweetness intensity: unflavored < lemon < vanilla. The two sessions with and without nose clip differed statistically in sweetness, highlighting that the aromas impacted the perceived sweetness but not the mouthfeel in vanilla samples. The study suggests that congruent aromas could modify the perceived sweetness in plant-based yogurts; however, aroma or perceived sweetness does not impact the mouthfeel in plant-based yogurts. While the odor−taste interaction in such products is evident, the study highlights that aroma compounds alone do not modify mouthfeel.

Effects of brewing conditions and coffee species on the physicochemical characteristics, preference and dynamics of sensory attributes perception in cold brews

The study aimed to assess the dominant sensory attributes and preference for cold brews prepared with different coffee species under different brewing conditions. Four beverages were brewed using Arabica and Robusta coffees with either a coarser coffee grind and extraction at 5 °C or a finer grind and extraction at 15 °C. Coffee flavor and bitter taste were dominant sensory attributes of all beverages, regardless of material and preparation. While there were no differences in preference, the composition and dominant sensory attributes differed among the cold brews. The use of different coffee species had a greater impact on the composition and the perception of the attributes of the cold brews than brewing conditions. Sourness and coffee flavor were more dominant in Arabica cold brews, which had higher trigonelline content and acidity, but bitter taste dominance was further reported. Meanwhile, bitterness and astringent sensation were more dominant in Robusta cold brews, with higher caffeine and total chlorogenic acid content; however, a high coffee flavor dominance was also observed.

Comparison of the Chemical and Sensorial Evaluation of Dark Chocolate Bars

As it mimics olfactory perception, headspace analysis is frequently used for examination of products like chocolate, in which aroma is a key feature. Chemical analysis by itself, however, only provides half the picture, as final consumer’s perception cannot be compared to that of a Gas Chromatography-Mass Spectrometry (GC-MS) port, but rather to a panel test assessment. The aim of the present study was the evaluation of combined chemical (by means of headspace solid-phase microextraction and GC-MS) and panel test data (by means of a sensory evaluation operated by 6 untrained panelists) obtained for 24 dark chocolate bars to assess whether these can discriminate between bars from different brands belonging to different commercial segments (hard discount, HD; supermarket, SM; organic bars, BIO). In all samples, with the only exception of one supermarket bar (in which esters exhibited the highest relative abundance), pyrazines were detected as the most abundant chemical class (HD: 56.3–74.2%; BIO: 52.0–76.4%; SM: 31.2–88.9%). Non-terpene alcohols, aldehydes, and esters followed as quantitatively relevant groups of compounds. The obtained data was then subjected to hierarchical cluster (HCA) and principal component (PCA) analysis. The statistical distribution of samples obtained for the chemical data did not match that obtained with panelists’ sensorial data. Moreover, although an overall ability of grouping samples of the same commercial origin was evidenced for hard discount and supermarket bars, no sharp grouping was possible.

Commercializing Sonic Seasoning in Multisensory Offline Experiential Events and Online Tasting Experiences

The term "sonic seasoning" refers to the deliberate pairing of sound/music with taste/flavour in order to enhance, or modify, the multisensory tasting experience. Although the recognition that people experience a multitude of crossmodal correspondences between stimuli in the auditory and chemical senses originally emerged from the psychophysics laboratory, the last decade has seen an explosion of interest in the use and application of sonic seasoning research findings, in a range of multisensory experiential events and online offerings. These marketing-led activations have included a variety of different approaches, from curating pre-composed music selections that have the appropriate sonic qualities (such as pitch or timbre), to the composition of bespoke music/soundscapes that match the specific taste/flavour of particular food or beverage products. Moreover, given that our experience of flavour often changes over time and frequently contains multiple distinct elements, there is also scope to more closely match the sonic seasoning to the temporal evolution of the various components (or notes) of the flavour experience. We review a number of case studies of the use of sonic seasoning, highlighting some of the challenges and opportunities associated with the various approaches, and consider the intriguing interplay between physical and digital (online) experiences. Taken together, the various examples reviewed here help to illustrate the growing commercial relevance of sonic seasoning research.

Revealing dynamic changes of the volatile profile of food samples using PTR-MS

Volatile compounds carry valuable information regarding the properties of foodstuffs. Volatiles emitted from food can be used as, for example, indicators of quality, shelf-life, or authenticity. A better understanding of the multitude of transformations which occur during food processing could facilitate the optimisation of production, increase the desirability of food products, and also their wholesomeness. However, as some of these transformations are fast-paced, it is necessary to monitor them using techniques which enable real-time determination of volatiles, such as proton transfer reaction-mass spectrometry (PTR-MS). Recent years have seen a marked increase in its use in food analysis, since it can be used to obtain insight into the dynamics of the monitored processes and can be the basis for precise quality control methods for food processing. This review highlights recent works in which PTR-MS was used in monitoring during foodstuffs production, preparation and storage.

Sonic Seasoning and Other Multisensory Influences on the Coffee Drinking Experience

The coffee drinking experience undoubtedly depends greatly on the quality of the coffee bean and the method of preparation. However, beyond the product-intrinsic qualities of the beverage itself, there are also a host of other product-extrinsic factors that have been shown to influence the coffee-drinking experience. This review summarizes the influence of everything from the multisensory atmosphere through to the sound of coffee preparation, and from the typeface on the coffee packaging through the drinking vessel. Furthermore, the emerging science around sonic seasoning, whereby specific pieces of music or soundscapes, either pre-composed or bespoke, are used to bring out specific aspects in the taste (e.g., sweetness or bitterness) or aroma/flavor (nutty, dark chocolate, dried fruit notes, etc.) of a coffee beverage is also discussed in depth. Relevant related research with other complex drinks such as beer and wine are also mentioned where relevant.

Arousal influences olfactory abilities in adults with different degree of food neophobia

Food neophobia, i.e., the aversion to novel foods, and olfaction are both factors strongly affecting food choices. Mounting evidence suggests a higher arousal towards food as a key factor underlying the reluctance to eat what is unfamiliar to us. As the role of olfaction behind this phenomenon is poorly understood, we explored the associations between food neophobia and trait anxiety, olfactory functions (odor threshold, discrimination and identification) and retronasal aroma release from a reference food in a healthy cohort of 83 adult volunteers. We grouped participants in Low-Neophobics or neophilics (n = 35), Medium-Neophobics (n = 32) and High-Neophobics (n = 16) according to the widely recognized Food Neophobia Scale. Participants with higher neophobic tendencies were found to have marginally higher trait anxiety levels than neophilics (p = 0.10). A lower global olfactory functioning and odor discrimination abilities characterized High-Neophobics, while Medium-Neophobics showed a higher odor sensitiveness than Low-Neophobics. Lastly, High-Neophobics showed a lower extent of retronasal aroma release, likely due to a shorter duration of oral processing and higher anxiety-related physiological responses (such as breathing rate). In summary, this study supports the assumption that the conflicting relationship that neophobics have with food may be led by higher levels of arousal toward foods, rather than different chemosensory functions.

Modulation of aroma release of instant coffees through microparticles of roasted coffee oil

We report, on the successful addition of spray-dried microparticles containing roasted coffee oil, to soluble coffee (SC) and instant cappuccino (IC), to increase and tailor aroma release. Using PTR-ToF-MS (Proton Transfer Reaction Time-of-Flight Mass Spectrometry), five parameters were defined from time series intensity for each VOC, to compare the performance of different products: total area under the curve (AUC), area under the curve of burst (AUC-burst), maximum signal intensity, final intensity (5 min), and ratio AUC-burst/AUC. Microparticles with higher loads of roasted coffee oil were effective in increasing aroma intensity in SC while, for IC, all loads of microparticles improved aroma intensity. Volatility drove the VOC release in SC, and volatility and polarity for IC. Most compounds reached maximum headspace concentration in < 16 s upon start of reconstitution. These results open new perspectives for the development of instant coffee products and demonstrate their unique aroma release characteristics.

Cocoa smoky off-flavour: A MS-based analytical decision maker for routine controls

Cocoa smoky off-flavour is generated from an inappropriate artificial drying applied on beans to speeding up the post-harvest process and it can affect the quality of the chocolate. The sensory tests are time-consuming, and at present, a fast analytical method to detect this defect in raw materials is not yet available. This study applies a HS-SPME-MS-enose in combination with chemometrics to obtain diagnostic mass-spectral patterns to detect smoked samples and/or as analytical decision maker. SIMCA models provide the best classification results, compared to PLS-DA, with sensitivities exceeding 90% and a high class specificity range of 89-100% depending on the matrix investigated (beans or liquors). Resulting diagnostic ions were related to phenolic derivatives. The discrimination ability of the method has been confirmed by a quantitative analysis through HS-SPME-GC-MS. HS-SPME-MS-enose turned out to be a fast, cost-effective and objective approach for high throughput analytical screening to discard defective cocoa samples.

Sensory and monosaccharide analysis of drip brew coffee fractions versus brewing time

BACKGROUND

The composition of drip brew coffee versus brewing time has been chemically characterized in previous studies, and it is known that the total dissolved solids (TDS) systematically decreases with each fraction during the brew. Little information exists regarding the corresponding sensory attributes versus time, however, and it is unclear how TDS correlates with flavor profile.

RESULTS

Standard drip brews were fractionated into distinct samples by switching in an empty carafe every 30 s during the brew. Using a trained sensory descriptive panel, we found that most taste and flavor attributes decreased with brew time; for example, the earlier fractions were systematically more bitter and more sour than later fractions. Surprisingly, however, several flavor and taste attributes increased in time; for example, later fractions were systematically sweeter and more floral than earlier fractions. Since later fractions had lower TDS, these results indicate that perceived sweetness in drip brew coffee is negatively correlated with TDS. Mass spectrometry measurements of the monosaccharide content in the brews showed that none of the fractions had perceptible concentrations of any monosaccharide.

CONCLUSION

The results of the sensory analysis and the monosaccharide analysis suggest that perceptible sweetness in coffee is a consequence of masking effects and/or the presence of sweet-associated aromas and flavors. The results further suggest that unique flavor profiles could be obtained from the same coffee grounds by judicious combinations of specific fractions. © 2020 Society of Chemical Industry.

Novel experimental approach to study aroma release upon reconstitution of instant coffee products

This study presents an experimental approach to study the kinetics and fast release of volatile organic compounds (VOCs) upon reconstitution of instant coffee products. A sampling setup coupled to PTR-ToF-MS (Proton Transfer Reaction Time-of-Flight Mass Spectrometry) for the automated and reproducible reconstitution of instant coffee products was developed to monitor the dynamic release of VOCs. A rapid release of aroma compounds was observed in the first seconds upon hot water addition ("aroma burst"), followed by subsequent decrease in headspace (HS) intensities over the course of analysis. Differences in time-intensity release profiles of individual VOCs were correlated to their Henry's Law constant, vapor pressure and water solubility. The setup and approach proposed here have shown to be sensitive and to respond to fast dynamic changes in aroma release. It allows studying VOCs release upon reconstitution and supports the development of novel technologies and formulations for instant products with improved aroma release properties.

HS-SPME-MS-Enose Coupled with Chemometrics as an Analytical Decision Maker to Predict In-Cup Coffee Sensory Quality in Routine Controls: Possibilities and Limits

The quality assessment of the green coffee that you will go to buy cannot be disregarded from a sensory evaluation, although this practice is time consuming and requires a trained professional panel. This study aims to investigate both the potential and the limits of the direct headspace solid phase microextraction, mass spectrometry electronic nose technique (HS-SPME-MS or MS-EN) combined with chemometrics for use as an objective, diagnostic and high-throughput technique to be used as an analytical decision maker to predict the in-cup coffee sensory quality of incoming raw beans. The challenge of this study lies in the ability of the analytical approach to predict the sensory qualities of very different coffee types, as is usual in industry for the qualification and selection of incoming coffees. Coffees have been analysed using HS-SPME-MS and sensory analyses. The mass spectral fingerprints (MS-EN data) obtained were elaborated using: (i) unsupervised principal component analysis (PCA); (ii) supervised partial least square discriminant analysis (PLS-DA) to select the ions that are most related to the sensory notes investigated; and (iii) cross-validated partial least square regression (PLS), to predict the sensory attribute in new samples. The regression models were built with a training set of 150 coffee samples and an external test set of 34. The most reliable results were obtained with acid, bitter, spicy and aromatic intensity attributes. The mean error in the sensory-score predictions on the test set with the available data always fell within a limit of ±2. The results show that the combination of HS-SPME-MS fingerprints and chemometrics is an effective approach that can be used as a Total Analysis System (TAS) for the high-throughput definition of in-cup coffee sensory quality. Limitations in the method are found in the compromises that are accepted when applying a screening method, as opposed to human evaluation, in the sensory assessment of incoming raw material. The cost-benefit relationship of this and other screening instrumental approaches must be considered and weighed against the advantages of the potency of human response which could thus be better exploited in modulating blends for sensory experiences outside routine.

Sensory Influence of Sweetener Addition on Traditional and Decaffeinated Espresso

Several factors have led to an increase in the consumption of sweeteners in substitution of sucrose. Studies on the behavior and the sensory properties of sweeteners are relevant, once they provide knowledge about both the adequate sweetener concentration with a sweetness equivalence to a sucrose-sweetened product and the possible sensory changes of the product. The addition of stevia with different rebaudioside A concentrations and sucralose to traditional and decaffeinated espresso coffee was studied, using the just-about-right scale and magnitude estimation method, to determine the ideal sweetness and the acceptance of the samples. The effect of the intensity of sensory attributes sweet taste, bitter taste, coffee flavor, and body in the acceptance was evaluated by penalty analysis. Decaffeinated presented proportionally lower sucrose concentration and sweetness equivalence than the traditional samples. Stevia concentrations were similar, despite the different rebaudioside A concentrations, for both traditional and decaffeinated samples, and rebaudioside A levels from stevia in espresso have no differences in sweetness intensity. Sucralose was the most intense sweetener in espresso. Although no differences were observed in the acceptance test in relation to appearance, aroma, and texture among the samples, the internal preference map showed segmentation of consumers with respect to the acceptability. This segmentation is more related to the type of sample than the added sweetener. Penalty analysis demonstrated that the most penalizing sensory characteristics were "coffee flavor" and "sweet," leading to a significant decrease in the acceptability of the samples. PRACTICAL APPLICATION: Conclusions obtained are important source of knowledge for the coffee industry, in the development and manufacture of beverages with coffee. The present findings can help to understand the behavior and the sensory properties of sweeteners. They provide knowledge about sensory perception of sweet and bitter tastes, and the factors that influence this perception and the sensory profile of the samples, once the behavior of sweeteners varies according to the product to which they are added.

Ethnicity, gender and physiological parameters: Their effect on in vivo flavour release and perception during chewing gum consumption

In this study, the impact of physiological parameters, ethnicity and gender on flavour perception and flavour release of chewing gum was investigated. Proton Transfer Reaction Mass Spectrometry in-nose monitoring of volatile organic compounds was coupled to discontinuous time intensity sensory evaluation for mint flavour and sweetness perception. Each of the 29 subjects, 14 European and 15 Chinese panelists (13 male and 16 females, age 24 ± 1.4 years old) consumed the samples in triplicates. Physiological parameters (oral cavity volume, salivary flow, acetone and isoprene concentration and fungiform papillae density) were measured. Significant differences for in vivo flavour release between Chinese and European panelists after 90 s of consumption and after the gum was removed from the mouth were found. Significant differences were observed also in flavour and sweetness perception while no gender effect was detected. In this work, for the first time an effect of ethnicity on in-nose flavour release monitored through PTR-MS was noticed during chewing gum consumption, in agreement with the findings from sensory evaluation. Single physiological parameters do not explain the relation between flavour in nose release and perception during consumption.

Which cocoa bean traits persist when eating chocolate? Real-time nosespace analysis by PTR-QiToF-MS

More consumers have become aware of the existence of different cocoa genotypes and their origins, which resulted in a growing market of premium chocolates with single-origin beans. The question is whether traits of cocoa botanical and geographical origins still persist in the end product, especially when it is consumed. By analysing the concentrations of volatile organic compounds (VOCs) in the nose of subjects over time while they are eating, new insights about aroma release can be gained. In the current study, in vivo release of VOCs during consumption of dark chocolates with different botanical and geographical origins was examined. Proton Transfer Reaction-Quadrupole interface Time of Flight- Mass Spectrometry (PTR-Qi ToF- MS) was applied to analyse nosespace VOC profiles of 10 subjects while they were eating 10 different chocolates manufactured with beans of different botanical origins (Criollo-Forastero-Trinitario) and geographical origins (Africa-South America-Asia). The headspace of the chocolates were also analysed for comparison. Cocoa botanical information appeared to affect the nosespace profiles more than geographical information. The subjects varied considerable in their VOC release, and inter-individual differences were larger than cocoa beans differences. Nevertheless, the botanical origin was consistently reflected in the nosespace profile during eating. It was clearly possible to distinguish Criollo chocolates from the nosespace profiles despite inter-individual differences.

Multi-Sip Time⁻Intensity Evaluation of Retronasal Aroma after Swallowing Oolong Tea Beverage

In most cases, a meal cannot be finished with a single bite and sip. During eating and drinking, consumers receive dynamic food perceptions from sensory attributes in foods. Thus, we performed multi-sip time–intensity (TI) evaluation of sensory attribute. In each of ten trials, the participant evaluated continuously the intensity of retronasal aroma for 60 s after swallowing oolong tea. We compared the TI parameters (I_max: maximum intensity, T_max: time point at which intensity reached the maximum value, AUC: area under the TI curve, D_plateau: duration between the first and last time points with values exceeding 90% of the maximum intensity, R_inc: rate of intensity increase between the first time points with values exceeding 5% and 90% of the maximum intensity, and R_dec: rate of intensity decrease between the last time points with values exceeding 5% and 90% of the maximum intensity) and TI curves among the ten trials, and approximated each TI curve with an exponential model. Some TI parameters (I_max, T_max, AUC, and R_inc) differed significantly between the first and subsequent trials. The TI curve was significantly lower in the first trial than in the subsequent trials, and TI curve during the time from starting the evaluation to reaching maximum intensity was significantly lower in the second trial than in the subsequent trials. The time constant of the fitted exponential function revealed that the decay of retronasal aroma intensity was slightly faster in the second through fourth trials than in the first and the fifth through tenth trials. These results indicate that olfaction might be more perceptive while consumers sip a cup of the beverage.

Evaluation of PTR-ToF-MS as a tool to track the behavior of hop-derived compounds during the fermentation of beer

Hop-derived volatile organic compounds (VOCs) play an important role in the flavor and aroma of beer, despite making up a small percentage of the overall profile. To understand the changes happening during fermentation, proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) was applied for the first time in brewing science to directly measure the changes in hop-derived VOCs during the fermentation of four different worts containing one of two aroma hops in combination with one of two yeast biotypes. PTR-ToF-MS successfully detected and tracked mass-to-charge ratios (m/z) arising from interactions between the different yeast strains and the hop cultivars. Differences were observed in the dynamic VOC profiles between different beer treatments for m/z such as m/z 145.121 (ethyl hexanoate) and m/z 173.153 (isoamyl isovalerate or ethyl octanoate). The ability to monitor changes in VOCs during fermentation provides valuable information on the priority of production and transformation reactions by yeast.

Model cheese aroma perception is explained not only by in vivo aroma release but also by salivary composition and oral processing parameters

The aim of the present paper was to determine, from four model cheeses differing in fat content and firmness, the respective impacts ofin vivoaroma release, bolus rheology, chewing activity, mouth coating and salivary composition on dynamic aroma perception.

Static and dynamic headspace analysis of instant coffee blends by proton-transfer-reaction mass spectrometry

Instant coffee is a widespread product, generally related to a high consumer acceptability, also because of its ease of preparation. The present work addresses the characterization of the headspace of freshly brewed instant coffees resulting from different blends, during and immediately after preparation. The sample set consisted of 10 coffees, obtained by mixing three different blends in different proportions. The employment of Proton Transfer Reaction-Mass Spectrometry (PTR-MS) allowed for direct and real-time sampling from the headspace, under conditions that mimic those that are encountered above the cup during and right after brewing. Different coffee brews were separated on the basis of the respective volatile profiles, and data showed good consistency with the respective blend compositions. When the headspace evolution was monitored during preparation, similar results were obtained in terms of blend separation; moreover, different blends displayed different and reproducible 'signatures' in terms of time evolution. A straightforward method for the prediction of headspace composition is proposed, allowing to predict the volatile profiles of two-component and three-component blends on the basis of the respective parent components. Overall, the results constitute a successful example of the applicability of PTR-MS as a tool for product development in food science. Copyright © 2015 John Wiley & Sons, Ltd.