Emotions elicited while drinking coffee: A cross-cultural comparison between Korean and Chinese consumers

Consumers assess products not only based on their physical aspects but also on their emotion-evoking components. Many methods, such as EsSense Profile^®, GEOS, and ScentMove, have been developed for evaluating various kinds of products. Research has suggested the need for developing a specialized lexicon for specific food or beverage categories. The English emotion lexicon, the Coffee Drinking Experience¹(CDE), was developed specifically for coffee. However, while emotions can be expressed by words, they can also be affected by culture and context. Thus, our objectives are 1) to develop coffee emotion lexicons in Korean and Chinese, 2) to compare the differences of emotions evoked while consuming different kinds of coffee, and 3) to compare the differences between Chinese and Korean consumers while consuming the same coffee samples. To address these aims, we conducted two studies. First, we conducted a consumer-led translation of 86 emotion terms from the CDE into Korean and Chinese. Second, consumers checked the intensity of emotion terms while drinking six commercial coffee samples. The order of the Chinese and Korean consumers’ overall preferences was the same: all-in-one coffee received higher scores than black coffee. Finally, using a logistic stepwise regression analysis, the Chinese and Korean lexicons were reduced to 53 and 29 terms, respectively.     

The Kinetics and mechanism of caffeine infusion from coffee: Hydrodynamic aspects

Hydrodynamic flow conditions were controlled by means of large horizontal rotating discs. These were coated with ground and sieved Kenyan Arabica coffee, and rotated at various speeds in distilled water at 25°C. The rate of extraction of caffeine was measured in each experiment. At a constant rotation speed, the first order rate constant rose steeply with decreasing size of coffee particle and was found to be inversely proportional to the square of the particle radius. For a given particle size, however, the rate constants were independent of the rotation speed. These two findings show that the rate-determining step for extraction from coffee-coated discs was the diffusion of caffeine through the bean particle and not its diffusion through the Nernst layer. The same mechanistic conclusion can be drawn for stirred coffee suspensions by applying the hydrodynamics of turbulent flow.     

Pleasantness,emotions and perceptions induced by coffee beverage experience depend on the consumption motivation (hedonic or utilitarian)

Motivations to consume a given food or drink differ across consumers. For instance, coffee drinking can be motivated by sensory enjoyment (hedonic motivation) or by stimulation (functional motivation). Today it remains unknown how hedonic vs. utilitarian motivations impact consumer–product interaction. The objective of the present research was to study the impact of both motivations on consumer responses (i.e. pleasantness, emotions, and importance and satisfaction for each of the five senses) during the entire experience of a coffee beverage. Sixty participants drinking coffee beverage either for sensory enjoyment (SENS, n = 30) or to be stimulated (STIM, n = 30) were recruited. Four moments of the product experience were considered: water heating, jar handling, cup preparation and cup drinking. Self-ratings were repeatedly performed by the participants after each moment. SENS participants depicted higher positive emotions than STIM participants and even if similar levels of pleasantness were reached after cup drinking by both groups, levels of pleasantness at water heating and jar handling moments differed. The importance and satisfaction for the different senses also changed according to the participant motivation to drink the coffee beverage. Marketing implications are discussed in terms of communication materials development to more strongly engage consumers with the product.     

Stability of ochratoxin A (OTA) during processing and decaffeination in commercial roasted coffee beans

The fate of ochratoxin A (OTA) during the processing of artificially contaminated green coffee beans, the effect of decaffeination on the production of OTA in green and roasted coffee beans, and the effect of caffeine on the growth and OTA production by Aspergillus ochraceus were studied. The data indicated that the roasting, milling and decoction (brewing and Turkish coffee making) processes caused different percentage reductions in OTA. Decaffeinated samples showed a significantly higher concentration of OTA production than the caffeinated ones. A significantly higher percentage of OTA was reduced when the decaffeination process was performed before roasting treatment. Caffeine at 1.0 and 2.0% concentrations completely prevented OTA production and completely inhibited A. ochraceus growth in YES medium after 3-21 days.     

The kinetics and mechanism of caffeine infusion from coffee: The effect of particle size

Measurements have been made of the rate of infusion of caffeine into distilled water from medium roast Kenyan Arabica coffee beans and from eight sieved fractions of the ground beans at 25.8°C. The first-order rate constants increased dramatically as the particle size decreased. For one of the size fractions the rate constants were then measured at various temperatures up to 84.1°C and were found to rise eight-fold over this temperature interval. The partition coefficients of caffeine between ground beans and water were also determined. These results, interpreted by a new steady-state theory of extraction, show that the rate-determining step in the infusion is diffusion of caffeine through the swollen coffee particles. The low magnitude of the diffusion coefficient and its high activation energy demonstrate that caffeine diffusion within the bean particles is a hindered process.     

Ochratoxin A (OTA) in coffee: nation-wide evaluation of data collected by German Food Control 1995-1999

The evaluation process involved data collected by Official Food Control Laboratories during the period 1995 until 1999. A total of 613 samples analysed for ochratoxin A and complying with a detection limit lower than 0.6 microg/kg were evaluated. With the assistance of statistical process analysis the median concentrations for green coffee (0.4 microg/kg), for roasted coffee (0.6 microg/kg), for decaffeinated roasted coffee along with low-acid decaffeinated roasted coffee (0.4 microg/kg) as well as for soluble coffee (0.7 microg/kg) were determined. The result is a mean daily total intake per consumer of 9 ng OTA.     

Succession of bacterial and fungal communities during natural coffee (Coffea arabica) fermentation

Bacteria, yeasts and filamentous fungi were isolated during natural coffee processing. Bacteria were isolated in greater numbers at the beginning of the fermentation, when the moisture of the coffee beans was around 68%. Gram-positive bacteria represented 85.5% of all bacteria isolated, and Bacillus was the predominant genus (51%). Gram-negative species of the genera Serratia, Enterobacter and Acinetobacter were also found. Approximately 22% of 940 randomly chosen isolates of microorganisms were yeasts. Debaryomyces (27%), Pichia (18.9%) and Candida (8.0%) were the most commonly found genera, and these three genera tended to appear more often as the fruit was fermented and dried. Aspergillus was the most abundant genus besides Penicillium, Fusarium and Cladosporium, with 42.6% of the total fungi isolates. The genera and species identified included members known to have pectinase and cellulase activities. Of the 10 organic acids analyzed and quantified in coffee beans, acetic and lactic acids may have been generated by microbial activity. Butyric acid was not detected in any sample.     

The kinetics and mechanism of caffeine infusion from coffee: The hindrance factor in intra-bean diffusion

Green and medium-roast Kenyan arabica coffees were ground and sieved, and the 0·85–1·8 mm size fractions partially converted into two water-swollen forms by an appropriate series of treatments. The first form still contained a mix of coffee solubles, the second only caffeine. The rates of caffeine infusion into water at 80°C were then measured for the dry coffee and for the two water-swollen preparations. The caffeine was extracted two to three times faster from the solute-free water-swollen preparation than from the dry material Analysis of the results showed that counterflow of water the swelling of coffee particles, caffeine association with other solubes and physical restraints within the bean matrix all contribute to the low diffusion coefficient of caffeine inside the coffee particles. The behaviour of the green and the medium roast coffees was surprisingly similar.     

Mathematical modeling of intermittent and convective drying of rice and coffee using the reaction engineering approach (REA)

In order to extend shelf life of rice and coffee, drying can be conducted to minimize water content so that chemical and biological changes can be retarded. Several models have been proposed to model drying of coffee and rice. For design of dryer and evaluation of dryer performance, the effective and physically meaningful drying model should be implemented. The reaction engineering approach (REA) is applied in this study to model convective drying of coffee as well as convective and intermittent drying of rice. The REA is a unique approach to model drying; the physics of drying is captured by the relative activation energy which can be generated only from one accurate drying experiment. The relative activation energy can be applied to other conditions of drying provided the same material and similar initial moisture content. Results indicate that the REA describes the convective and intermittent drying of rice and coffee very well.     

The choice of probing sites by Bracon hebetor Say (Hymenoptera: Braconidae) foraging for Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

A direct behavioral assay was conducted to investigate the preferred habitat for host searching by the parasitoid Bracon hebetor (Hymenoptera: Braconidae). The effects of mating, feeding and post-emergence experience on female parasitoid choices of searching sites were also examined. B. hebetor appears to be directed to the habitat of its host through chemical cues originating from the host larvae, frass and adults. These cues elicit a series of directed responses by the female. Generally, the data showed that flour containing 30-day-old larvae was preferred by B. hebetor females. This was followed by the flour containing the frass, then the adult host, and finally the flour containing 10-day-old larvae. It appears that cues produced by young larvae were the weakest whereas cues produced by older ones were the strongest. Feeding seemed to be important in the location of the proper searching site. Although the cues were normally learned by the immature stages of the parasitoid, and were subsequently manifested in their responses as adults, adult experience increased the ability of the parasitoid to locate the suitable habitat for searching.     

Assessment of instructions on panelist cognitive framework and free sorting task results: A case study of cold brew coffee

As the free sorting task becomes more common in sensory science, methodological research is needed to determine best practices for the test. Previous studies have shown that asking attribute-specific, “analytical” questions can bias the answers participants give to later “holistic” questions in a survey. For the free sorting task, this has led researchers to recommend only asking subjects to label or describe groups of products after they have finished sorting, but this approach is not based on empirical research. The present study investigated whether the separation of sorting and labeling steps is necessary by having 80 panelists sort 12 cold brew coffee samples in 3 conditions: labeling and describing the groups afterwards, at the same time, or not at all. Results were analyzed with DISTATIS, Hierarchical DISTATIS, and permutation tests. This work is novel in investigating the effect of labeling instructions on sorting results and provides some interesting insight into sensory impact of coffee bean parameters on cold brew coffees. No configurational differences were found based on the timing of labeling instructions and 38% of panelists labeled their groups without being told, suggesting future researchers may request that subjects label when convenient. While the most distinctive samples were the dark roast coffees, a large subgroup (n = 36) sorted the coffee samples partially based on country of origin. Given the lack of effect from different sorting instructions and the tendency for spontaneous, simultaneous labeling, simultaneous labeling is suggested as best practice for future sorting tasks.     

Water content of roasted coffee: impact on grinding behaviour,extraction, and aroma retention

Normal and long time roasting trials were carried out on industrial scale. Different amounts of water were applied during quenching, resulting in water contents in the range of 2.3–8.8 g/100 g wb. Coffees were ground immediately after cooling, and after equilibration times of 6 and 24 h. Particle size distribution of ground coffees, percolation time, and extraction properties were investigated on an espresso coffee machine. Coffees ground after 24 h resting time were subjected to storage trials to determine aroma stability as influenced by water content. Coffees with high moisture content exhibited coarser particles upon grinding, and equilibration time prior to grinding was needed for coffees with high water content to improve grinding results. Coffees with low water content did not exhibit this time dependency prior to grinding. Coffees with low water content were extracted more effectively than high moisture coffees, and percolation was slower. During open and closed storage, evolution of hexanal and sulfides was highly sensitive to water content. However, differences in evolution of other aroma compounds were found during closed storage only, where moisture content had a negative impact on aroma stability of the coffees subjected to investigation.     

Identification of (furan-2-yl)methylated benzene diols and triols as a novel class of bitter compounds in roasted coffee

Preliminary studies demonstrated that the identification of unknown bitter taste compounds in roasted coffee, by means of an analytical fractionation approach, is hampered by their limited oxidative, as well as chemical stability. A synthetic-constructive strategy was followed in the present investigation by performing targeted reactions of putative coffee-related precursors to give candidate bitter taste molecules. Binary mixtures of a di and trihydroxybenzene, namely pyrogallol, hydroxyhydroquinone, catechol, or 3- and 4-methylcatechole, and a furan derivative, namely furfuryl alcohol, furan-2-aldehyde, or 5-(hydroxymethyl)furan-2-aldehyde, all of which are known to be present in roasted coffee, were thermally treated. The reaction products were identified as (furan-2-yl)methylated benzene diols and triols, by means of LC–MS and NMR experiments, and their bitter taste thresholds determined by means of sensory analysis. Finally, LC–MS/MS studies verified the natural occurence of 4-(furan-2-ylmethyl)benzene-1,2-diol, 4-(furan-2-ylmethyl)benzene-1,2,3-triol, 4-(furan-2-ylmethyl)-5-methylbenzene-1,2-diol, and 3-(furan-2-ylmethyl)-6-methylbenzene-1,2-diol as a novel class of bitter taste compounds in roasted coffee. Depending on their chemical structure, the bitter taste recognition threshold of these compounds ranged between 100 and 537 μmol/l.     

Combined effect of cold atmospheric plasma,intrinsic and extrinsic factors on the microbial behavior in/on (food) model systems during storage

Microbial decontamination by means of cold atmospheric plasma (CAP) offers great potential for treatment of heat-sensitive food products, extending their storage life. CAP is created by applying a high voltage to a gas stream, resulting in microbial inactivation according to different mechanisms. This paper thoroughly assesses the influence of CAP on the storage life of food model systems inoculated with Salmonella Typhimurium. (Food) model systems, with varying intrinsic factors (pH, salt concentration, and food (micro)structure), are treated for 5 min using a dielectric barrier discharge reactor generating a helium‑oxygen plasma. Following treatment, the impact of extrinsic factors is evaluated by storage at 8 °C or 20 °C. During storage, cell densities are determined. Data are fitted with predictive (growth or inactivation) models. As additional experiments indicate that the CAP treatment itself has a limited or even negligible effect on the properties of the model system (pH, a_w, (micro)structure), the microbial behavior of CAP treated samples during storage can be attributed to the treatment. CAP treatment can result in microbial reductions up to 2.7 log₁₀ and prolongs storage, however its rate of success is dependent on both extrinsic and intrinsic factors. An important factor is the storage temperature, as recovery of CAP treated cells proves more difficult when stored at 8 °C. At 20 °C, cell growth is merely slowed down. Additionally, at pH 5.5, 6% (w/v) NaCl, osmotic stress is induced on the microorganisms, which results in low cell recovery or further inactivation. The influence of the food (model) structure on the storage behavior is insignificant.Industrial relevanceAlthough being a very promising technology, most studies regarding the use of cold atmospheric plasma (CAP) for food decontamination focus on the inactivation of a target microorganism, in relation to a specific food product. Fundamental knowledge on this non-thermal technology, including its impact on the storage life, is lacking. This study investigates the effect of CAP on the microbial behavior during storage. By performing tests on model systems, for a variation of intrinsic and extrinsic factors, this work renders information on the suitability of this novel technology regarding treatment of a broad spectrum of food products. Moreover, this study demonstrates the limited impact of CAP on the food (model) properties, enhancing the suitability of the technology to be implemented in the food industry.     

Tough package, strong taste: The influence of packaging design on taste impressions and product evaluations

This study examines the influence of packaging design on taste impressions. Building forth on research addressing transfer effects of symbolic associations from one sense to another, in this study it was studied if, and to what extent, potency-related associations portrayed by shape curvature and color saturation of yoghurt packages transfer to subsequent taste experiences. Furthermore, the influence of participants’ sensitivity to design was taken into account. Data were collected during a field study in the entrance hall of a large supermarket. Results indicate that associations portrayed by shape curvature in particular transfer to taste experiences, but that these effects are most pronounced for participants with a sensitivity to design. In addition, the findings presented indicate that shape curvature and color saturation may impact more general product evaluations and price expectations as well.     

The impact of information on taste ranking and cultivation method on rice types that protect endangered birds in Japan: Non-hypothetical choice experiment with tasting

We investigate consumers’ reactions to information on rice types produced using a cultivation method that protects the crested ibis (Nipponia nippon), a symbol of the endangered birds of Japan. We employ a non-hypothetical choice experiment with real monetary incentives, in which participants taste three types of rice—Niigata rice, Sado rice, and Sado-Ibis certified rice (Ibis rice)—and choose one to take home. The participants make decisions twice in each choice set, once before and once after tasting. Three information treatments are used: information about taste ranking from chefs and consumers, cultivation method, and no-information. Comparing the expected and actual willingness to pay (WTP) for Ibis rice, only the cultivation method information increases the WTP, which triples. The WTP in the taste ranking information treatment becomes lower among the participants who refer to chefs, but there is no significant difference in preferences between the expected and actual stages among all participants. For Sado rice, the WTP increases when we provide no-information or information on the cultivation method. In both cases, the WTP changes from negative to positive relative to Niigata rice; however, this WTP is less than that for Ibis rice. These results imply that consumers are more sensitive to information of process and effort for a cultivation method that protects endangered species than to the information about taste ranking.     

不同植物材料对烟草甲成虫选择行为影响研究

本文采用Y型嗅觉仪在实验室内研究了臭椿树皮、蛇床子、高良姜根茎、木香薷、苍耳子、桂皮、艾叶、烟叶和麦粒（全麦粉）等植物材料对烟草甲成虫选择行为的影响。研究结果表明,烟叶、苍耳子、蛇床子、麦粒（全麦粉）对烟草甲成虫的引诱作用较强,烟草甲成虫的选择系数均在43.00%以上,其引诱的试虫数显著多于对照引诱的试虫数;全麦粉与烟叶粉末的引诱作用相当。臭椿树皮和高良姜根茎（正常状态和粉末状态）对烟草甲成虫均表现出较强的忌避性,烟草甲成虫对臭椿树皮和高良姜根茎的选择系数分别为-56.25%和-62.50%,二者气味源中的试虫数显著少于对照。因此,所测试的植物材料在调控烟草甲行为防治害虫方面具有的巨大开发应用潜力。      

The influence of training and expertise on the multisensory perception of beer: A review

This review critically evaluates the literature documenting the impact of training on people’s perception of beer. In certain circumstances, training has been shown to improve people’s ability to match and identify beers, and to discriminate between beers and between the distinctive attributes of beer. However, a reasonably consistent finding is that the benefits of beer training do not seem to generalise to novel beers (i.e., those not experienced during training). As such, training would appear to improve the capacity to label perception and/or people’s recognition memory for beers, rather than necessarily influencing perception itself. Given how much beer is consumed annually, it is surprising that there has not been more published research into the role that training plays in this particular beverage category. Part of the reason for this may relate to (a) the limited role of experts in this field (e.g., primarily restricted to product testing and quality control; as compared to their much more prominent role in the world of wine), (b) the fact that training is an expensive and time-consuming process, and (c) it is wrongly assumed that the effects of training are similar across different beverage categories (e.g., beer and wine). We suggest that further efforts are therefore required before it will be possible to confidently conclude that training lowers the perceptual thresholds, and enhances the perceptual discrimination abilities, of beer experts above those of novices.