Development of a Time–Intensity Evaluation System for Consumers: Measuring Bitterness and Retronasal Aroma of Coffee Beverages in 106 Untrained Panelists

In order to develop products that are acceptable to consumers, it is necessary to incorporate consumers’ intentions into products’ characteristics. Therefore, investigation of consumers’ perceptions of the taste or smell of common beverages provides information that should be useful in predicting market responses. In this study, we sought to develop a time–intensity evaluation system for consumer panels. Using our system, we performed time–intensity evaluation of flavor attributes (bitterness and retronasal aroma) that consumers perceived after swallowing a coffee beverage. Additionally, we developed quantitative evaluation methods for determining whether consumer panelists can properly perform time–intensity evaluation. In every trial, we fitted an exponential function to measured intensity data for bitterness and retronasal aroma. The correlation coefficients between measured time–intensity data and the fitted exponential curves were greater than 0.8 in about 90% of trials, indicating that we had successfully developed a time–intensity system for use with consumer panelists, even after just a single training trial using a nontrained consumer. We classified participants into two groups based on their consumption of canned coffee beverages. Significant difference was observed in only AUC of sensory modality (bitterness compared with retronasal aroma) among conventional TI parameters using two‐way ANOVA. However, three‐way ANOVA including a time course revealed significant difference between bitterness and retronasal aroma in the high‐consumption group. Moreover, the high‐consumption group more easily discriminated between bitterness and retronasal aroma than the low‐consumption group. This finding implied that manufacturers should select consumer panelists who are suitable for their concepts of new products.     

Traditional Japanese confection overseas: Cultural difference and retronasal aroma affect flavor preference and umami perception

Food cultures differ among countries and regions. Yokan, a traditional Japanese confection, is culturally familiar to Japanese people but unfamiliar to Westerners. We investigated the effect of cultural differences and retronasal aroma on flavor preference for and taste perception of yokan among Japanese and German participants. As a control food, we also used the marshmallow, which is culturally familiar to both Japanese and German participants. Participants evaluated their preference for flavor as well as the intensity of the five basic taste qualities and retronasal aroma under the nostril-open and nostril-closed conditions. The retronasal aroma of a culturally familiar food significantly increased preference for flavor, whereas the retronasal aroma of a culturally unfamiliar food did not affect preference for flavor. Moreover, for all taste qualities, retronasal aroma induced a similar magnitude of taste enhancement between culturally familiar and unfamiliar foods, suggesting that cultural familiarity with a food does not affect taste perception. However, the retronasal aroma induced significantly greater umami enhancement in Japanese participants than in German participants, suggesting an effect of cultural familiarity with specific taste qualities on taste perception. These findings indicate that cultural differences and retronasal aroma affect flavor preference for and umami perception of food.     

Could cider aroma modify cider mouthfeel properties?

The objective of this work was to evaluate whether aroma–taste interactions could occur in cider due to cognitive interactions such as a dumping effect or a congruency phenomenon. Sixteen French ciders were selected with different organoleptic characteristics. Three different tasting conditions were compared in order to evaluate the presence of aroma interactions with taste. A trained panel was first asked to assess ciders, with and without a nose clip, on four attributes: sweetness, sourness, bitterness and astringency. Secondly, they had to score the same four attributes with seven aroma attributes added. It was shown that the perception of sweetness and astringency was modified in the presence of aroma. Ciders with fruity and caramel aromatic notes were perceived sweeter contrary to ciders with hay, animal and earthy notes, which were perceived less sweet. Moreover, the aroma interaction with sweetness was sugar concentration-dependent. It occurred only in cider containing around 40 g/L of sugar. Finally, ciders were perceived more astringent when tasted without wearing a nose clip.     

Differences in salivary flow and composition between age groups are correlated to dynamic retronasal aroma perception during wine consumption

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.     

Color Halo/Horns and Halo-Attribute Dumping Effects within Descriptive Analysis of Carbonated Beverages

ABSTRACT:  Training panelists to focus on and evaluate a specific set of attributes is difficult. While every attempt is made to eliminate bias, such as methodology, panel influence, and product differences, unknown halo/horns effects may still influence the data collected. The objectives of this research were to (1) determine if a halo/horns effect of color exists in evaluating commercial cola and lemon/lime flavored carbonated beverages, and (2) determine if a halo-attribute dumping effect on mouthfeel attributes exists by aroma, aroma-by-mouth, taste, and afterfeel attributes. Ten panelists were trained to describe aroma, aroma-by-mouth, mouthfeel, taste, and afterfeel attributes of carbonated beverages. Each of the 6 carbonated beverages was evaluated by 3 treatments: (1) as is , (2) mix no color , and (3) mix with color . In the 1st set of product evaluations, all products were evaluated for mouthfeel attributes alone. In the 2nd of product evaluations, all products were evaluated for aroma, aroma-by-mouth, mouthfeel, taste, and afterfeel attributes. Color halo/horns effects were shown on mouthfeel intensity scores of lemon/lime carbonated beverages when caramel color was added. Adding caramel color significantly increased (halo effect) perceived body and mouthcoating and significantly decreased (horns effect) bite, burn, numbing, and carbonation attributes. A halo-attribute dumping effect was observed when mouthfeel attributes were rated exclusively compared to when other attributes in the modalities of aroma, aroma-by-mouth, taste, and afterfeel were rated in addition to mouthfeel attributes. Perceived intensities of bite, burn, numbing, and astringent attributes significantly increased (halo-attribute dumping) when rated alone compared to when all attributes were rated.     

High consumption increases sensitivity to after-flavor of canned coffee beverages

BackgroundConsumers’ dietary habits affect perception of flavor attributes of common foods. One such flavor attribute is after-taste, but the definition of this term in the context of flavor perception is not consistent among studies. To address this issue, we refer collectively to the complex sensation perceived after swallowing or spitting out foods as “after-flavor”, and considered each flavor attribute (for example, bitterness and retronasal aroma) as a component of after-flavor. In this study, we examined how consumption of canned coffee beverages in daily life affects sensitivity to the after-flavor of these beverages. We performed time–intensity evaluation of bitterness and retronasal aroma after participants swallowed three different canned coffee beverages. We classified participants into two groups based on their consumption of canned coffee beverages in daily life: the relatively high-consumption group, who consumed at least one canned coffee beverages per week, and the relatively low-consumption group, who consumed less than one canned coffee beverages per week. We compared the time courses of perceived intensity of bitterness and retronasal aroma between these two groups.ResultsTime courses of perceived intensity of bitterness in two of the canned coffee beverages, and retronasal aroma in all three canned coffee beverages were significantly higher in the relatively high-consumption group.ConclusionsFamiliarization with canned coffee beverages due to increased consumption in daily life might significantly promote sensitivity to the after-flavor of such beverages.     

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.     

Modification of perceived beer bitterness intensity,character and temporal profile by hop aroma extract

The effect of hop aroma on perceived bitterness intensity, character and temporal profile of beer was investigated. A hop aroma extract was added at 3 levels (0, 245, 490 mg/L) to beers at low, medium and high bitterness. Beers were evaluated for perceived bitterness intensity, harshness, roundedness and linger by a trained panel using a rank-rating technique at each bitterness level, with and without nose clips. The use of nose clips enabled the olfactory aspect to be decoupled from taste and mouthfeel aspects of bitterness perception. Results showed significant modification of perceived bitterness in beer by hop aroma depending on the inherent level of bitterness. These modifications were mainly driven by olfaction – in an example of taste-aroma interactions, as well as certain tactile sensations elicited by the hop aroma extract in the oral cavity. At low bitterness, beers with hop aroma added were perceived as more bitter, and of ‘rounded’ bitterness character relative to those without hop aroma. When judges used nose clips, this effect was completely eliminated but the sample was perceived to have a ‘harsh’ bitterness character. Conversely, at high bitterness, even when nose clips were used, judges still perceived beers containing hop aroma to be more bitter. These increases in bitterness perception with nose clips indicates the stimulating of other receptors, e.g. trigeminal receptors by hop aroma extract, which in tandem with the high bitterness, cause perceptual interactions enhancing bitterness intensity and also affecting bitterness character. Bitterness character attributes such as ‘round’ and ‘harsh’ were found to significantly depend on bitterness and aroma levels, with the second level of aroma addition (245 mg/L) giving a ‘rounded’ bitterness in low bitterness beers but ‘harsh’ bitterness in high bitterness beers. The impact of aroma on temporal bitterness was also confirmed with time-intensity measurements, and found to be mostly significant at the highest level of hop aroma addition (490 mg/L) in low bitterness beers. These findings represent a significant step forward in terms of understanding bitterness flavour perception and the wider impact of hop compounds on sensory perception.     

Dynamic changes in the volatiles and sensory properties of chilled milk during exposure to light

Exposure of milk to light causes photo-oxidation and off-flavour generation. To characterise these reactions, semi-skimmed (1.5% fat) and whole (3.8% fat) extended shelf-life cows' milk were exposed to light for 20–48 h at 4 °C and volatiles in the milk headspace were measured on-line using proton-transfer-reaction mass spectrometry (PTR-MS). The flavour of the whole-milk was assessed by aroma profile analysis on both orthonasal/retronasal odour and taste after 0, 0.25, 1, 6 and 24 h light-exposure. Sensory changes perceived in milk exposed to light for up to 6 h varied in intensity and between replicates, most notably a transient sensory defect being detectable after 0.25 h exposure, but these changes did not correspond to any volatile organic compound (VOC) generation detected by PTR-MS. After 24 h, several compounds showed enhanced release profiles. Principal components analysis related these VOCs to changes in the sensory properties of the milk, described as oxidised/rancid/hay-like.     

A study on texture–taste–aroma interactions: Physico-chemical and cognitive mechanisms

Texture–taste, texture–aroma and aroma–taste interactions were examined in custard desserts varying in viscosity (at identical composition), sucrose level and aroma nature. All reciprocal interactions were investigated, with each binary interaction addressed through an independent sensory study. Rheological, in vivo aroma release and sucrose release measurements were run in parallel to control for a possible physico-chemical origin of these interactions. Observed interactions were found to be dependent upon the nature of the sensory modalities involved; physico-chemical mechanisms could only in some instances entirely explain these interactions. Taste and aroma did not impact texture perception and this was linked to the fact that rheological properties of the desserts were not modified. Texture affected the taste intensity but not the aroma intensity. Discrepancies between these sensory results and the physico-chemical results were observed. Aroma influenced taste perception and vice-versa, likely through cognitive mechanisms.     

Influence of type,concentration and flow behaviour of hydrocolloid solutions on aroma perception

The effects of the addition of two hydrocolloids—locust bean (LBG) and xanthan gums—at two concentrations (0.2 and 0.5%, w/v) on the intensity of the aroma of limonene and of isopentyl acetate solutions was studied using the pairwise ranking test. Previously, the rheological behaviour of the studied gums was analysed, finding that while LBG solutions were slightly pseudoplastic at the lower concentration and more so at the higher one, the xanthan solutions were clearly pseudoplastic at both concentrations. Addition of 0.2% LBG did not alter the limonene aroma intensity perceived, but on adding 0.5% LBG, above the coil overlap concentration (c*), the decrease in aroma intensity was significant. Addition of xanthan gum at any concentration did not modify the limonene aroma intensity perceived by judges, which can be attributed to the low value of c* for solutions of this gum. No difference in isopentyl acetate aroma was found among samples.     

Aroma–taste interactions between a model cheese aroma and five basic tastes in solution

The flavour perception of cheese results from complex sensory interactions between tastes and aromas. Using a model cheese solution, this study investigated perceived interactions between each of five basic tastes and a cheese aroma mixture containing ten volatile compounds commonly found in cheese. The five tastes – sucrose (sweetness), sodium chloride (NaCl) (saltiness), monosodium glutamate (MSG) (umami), lactic acid (sourness), and caffeine (bitterness) – were individually mixed with cheese aroma in water using a 5 taste level (0.2 log series) by 3 aroma level (0.5 log series) design. Aroma controls with no added taste were also included. This resulted in 18 samples for each single taste–aroma combination. An additional 18 samples were produced using a mixture of all 5 tastes with the 3 aroma levels. A panel of trained assessors (n = 10) evaluated cheese flavour intensity and taste intensity using 100 point line scales. Evaluation was carried out in duplicate, with samples grouped by taste type; 1 evaluation session per taste per replicate. Within type, order of presentation was balanced, and taste type order was randomised between replicates. Cheese flavour intensity was enhanced by sucrose and NaCl, while being suppressed by lactic acid. NaCl enhanced cheese flavour intensity the most at high aroma level, while lactic acid suppressed the most at low aroma level. When MSG level was increased, cheese flavour intensity was enhanced at both low and medium aroma levels, but was suppressed at the high aroma level. The greatest enhancement of cheese flavour intensity was found with the mixture of 5 tastes. Aroma significantly enhanced umami and bitterness, but did not enhance sweetness, saltiness, or sourness. This study showed that the perceived interaction between taste and cheese aroma depended on taste type and on the concentration levels of both taste type and aroma. The mixture of tastes was more effective at enhancing cheese flavour intensity than single tastes. This study provides knowledge that will underpin further study of taste–aroma interactions in a model cheese that aims to optimise cheese flavour intensity and character.     

Interaction between starch and aroma compounds as measured by proton transfer reaction mass spectrometry (PTR-MS)

The interaction between starch and the complexing aroma compounds hexanal and menthone was investigated by headspace analysis using proton transfer reaction mass spectrometry (PTR-MS). Starch systems with non-modified and modified tapioca starch were prepared containing single aroma compounds (hexanal, menthone) or a blend of the two aroma compounds at low aroma concentrations (6 × 10⁻³ mg/100 g). The headspace intensity of starch–aroma systems was slightly reduced due to starch–aroma interactions compared to aroma water-systems. The combination of hexanal and menthone did not lead to competitive aroma release effects, but hexanal retention increased by increasing the equilibration time from 48 to 96 h. Non-modified and chemically modified starch showed similar aroma release behaviour. It is concluded that the formation of starch–aroma complexes influences aroma release, but that at low aroma concentration the dissociation of the complex is not hindered by the aggregation of amylose–aroma complexes.     

Operationally defined solubilization of copper and iron in human saliva and implications for metallic flavor perception

Metals such as copper and iron cause unpleasant taste perceptions. Metallic compounds come in contact with saliva before delivery to taste receptors. Therefore, it is assumed that interactions between saliva and metallic compounds affect the perceptions of metals. The aim of this study was to determine the solubilization of metals in saliva and to examine whether or not perceptions of metallic flavor are influenced by metal solubility in saliva. Ten trained panelists evaluated the sourness, bitterness, astringency, electric sensation, and rusty nail-like retronasal aroma of copper sulfate (CuSO₄·5H₂O, Cu) and ferrous sulfate (FeSO₄·7H₂O, Fe) dissolved in ultrapure water at different concentrations. Total and soluble metals were measured in the subjects’ saliva collected after tasting the samples using an inductively coupled plasma spectrometer. Approximately, 4.5–6.4% of Fe and 4.0–6.6% of Cu were retained in the saliva after expectoration. The proportion of soluble metal to total metal retained in saliva decreased from 0.68 to 0.29 for Cu and 0.019 to 0.0016 for Fe, as the metal concentration increased. In particular, Fe was solubilized in saliva at a maximum level of 4.5–4.6 μM, regardless of the metal concentration of the solution. The perceived intensities of sensory attributes showed positive linear relationships with log concentrations of total Cu, soluble Cu, and total Fe, but they did not have any relationship with soluble Fe. These results indicate that sensory perceptions of Fe were influenced mainly by the total Fe retained in saliva, whereas the perception of Cu was affected by soluble Cu as well as total Cu.     

Retronasal Odor of Dried Bonito Stock Induces Umami Taste and Improves the Palatability of Saltiness

A traditional Japanese umami‐rich stock, dried bonito stock, was reported to improve the palatability of a low‐salt diet due to its characteristic aroma. Two pathways are available for the presentation of odors: the orthonasal and retronasal pathways. Aroma is perceived through the orthonasal pathway. In contrast, retronasal application of odors is thought to evoke different sensations from the orthonasal pathway, which is typically perceived as taste and modifies taste. Therefore, the effect of retronasal odor on salt‐reduction might be different from that of aroma, that is, orthonasal odor. Thus, the effects of the retronasal odor of dried bonito stock on the enhancement and improvement of palatability upon salt reduction were examined using sensory evaluation. Moreover, the contributions to flavor expression and palatability of dried bonito stock were also investigated. Although the retronasal odor of dried bonito did not enhance saltiness, it improved the palatability of saltiness. In the presence of no tastants except 0.68% NaCl, a content 15% less than that of Japanese traditional soup, the retronasal odor of dried bonito generated umami, enhanced the suitability for dried bonito stock, and increased palatability. This indicates that the retronasal odor of dried bonito stock could improve the palatability of a salt‐reduced diet. These findings can be applied to the development of new seasonings for improving the palatability of salt‐reduced foods.     

Effects of texture and temperature on the kinetic of aroma release from model dairy custards

The structure of a foodstuff, and its perceived texture, are important characteristics involved in the sensory availability of flavour compounds released during the food consumption. This study identifies the effect of texture on the dynamic release of aroma compounds under simulated oral conditions (temperature and shearing). Two custard desserts, with two levels of texture but the same composition, flavoured with four aroma compounds, were analysed. The rheological behaviour of the custards and the release of aroma compounds (SPME analysis) were simultaneously followed, using a mouth simulator. The custard with the lowest texture level showed the highest kinetic release for all aroma compounds studied. With fast increase of temperature (10–25 °C), the decrease in viscosity of the custards and its impact on flavour release seemed to be less important than the heat transfer inside the products and its effect on partition of aroma compounds.