Sample temperatures can modulate both emotional responses to and sensory attributes of tomato soup samples

https://doi.org/10.1016/j.foodqual.2020.104005Get rights and content

Highlights

  • Panelists characterized tomato soup samples served at 25, 40, 55, and 70 °C.

  • A trained panel found that 5 of 29 sensory attributes changed with temperature.

  • Consumers’ emotional responses to tomato soup also changed with temperature.

  • Different water-temperatures evoked variation in emotional responses.

  • Temperature-induced sensory and emotional changes of foods should be considered.

Abstract

This study aimed to determine how sample temperatures affect sensory attributes of and emotional responses to tomato soup samples. Six professionally-trained panelists evaluated two tomato soup products randomly served at four temperatures: 25, 40, 55, and 70 °C, and rated intensities of 29 attributes. Trained panelists found that five attributes changed with sample temperature of tomato soup. A total of 103 consumers also evaluated the same tomato soup products served at four temperatures using check-all-that-apply (CATA) ballots related to sensory attributes and emotional responses. The 27 emotional and 20 sensory attributes differed significantly among samples of two product types served at four temperatures. A principal component analysis showed that variation in sensory attributes could better be explained by product type rather than sample temperature, while emotional-response variation was attributed more to sample temperature than to product type. Sensory and emotional drivers of liking were also found to differ with sample temperature. Another study in which 66 consumers characterized sensory and emotional attributes of purified water at the four temperatures was conducted. Consumer emotional responses to water samples changed with sample temperature, while sensory perception varied only minimally. In conclusion, our findings provide empirical evidence that sample temperature significantly influences both emotional responses and sensory attributes, and temperature effects vary with the type of food.

Introduction

Consumer acceptability of foods and beverages is influenced by serving temperature. The acceptability of food and beverage items is generally maximized at their normal consumption temperatures (Cardello and Maller, 1982, Stokes et al., 2016, Zellner et al., 1988). Differences in consumer acceptability may be attributed to changes in temperature of test samples because previous studies using basic taste solutions have revealed that taste intensities differed with solution temperature (Bartoshuk et al., 1982, Lipscomb et al., 2016, Moskowitz, 1973; for a review, see Lemon, 2017). For example, cooler sucrose solutions were perceived as less sweet than warmer solutions (Calviño, 1986), perhaps due to slow adaptation on the tongue when the solution was warmer (Green & Nachtigal, 2012). Temperature-dependent bitterness perception was found to follow an inverted “U-shaped” trajectory. Adaptation of taste for quinine (but not caffeine) solution increased at temperatures between 21 °C and 37 °C (Green & Andrew, 2017), an opposite trend to that of sucrose solutions (Green & Nachtigal, 2012). Umami taste intensity in humans was also found to be a positive function of temperature when measured on the tongue tip, although this effect was not observed in testing the whole mouth (Green, Alvarado, Andrew, & Nachtigal, 2016). While temperature effects in salty solutions have not been clearly observed (Kim et al., 2015, Lipscomb et al., 2016), sourness was perceived to be most intense at 23 °C, in contrast to the perceptions at 3 °C or 60 °C (Lipscomb et al., 2016).

The effects of serving temperature on sensory perception have also been observed in more complex foods and beverages. For example, the aroma intensities of wines (Ross & Weller, 2008) and cheese soups (Kähkönen, Tuorila, & Hyvönen, 1995) have been found to differ as a function of serving temperature. In addition, solid foods such as cheddar cheese (Drake, Yates, & Gerard, 2005) and cooked rice (Yau & Huang, 1996) varied in odor, taste, flavor, or textural attributes as a function of serving temperature. It should be noted that the trends in sensory attribute intensities with respect to the effect of serving temperature have not been found identical for all foods, suggesting that different types of foods may follow different trends.

Previous studies have shown that ambient, warm, or cold temperature can affect perceived value of food products (Zwebner et al., 2014) and preference for food images, especially savory food images (Motoki, Saito, Nouchi, Kawashima, & Sugiura, 2018). A recent study found that food/beverage-evoked emotions, characterized as “a brief but intense physiological and/or mental reaction to a food or beverage item” (King & Meiselman, 2010), also varied depending on consumed sample temperatures (Pramudya & Seo, 2018a). More specifically, brewed coffee or green tea beverage samples evaluated at higher temperature (65 °C) were more frequently characterized as having positive emotional attributes than those evaluated at ambient (25 °C) or lower (5 °C) temperatures. While beverage samples evaluated at 5 °C were characterized more by emotional attributes of negative valence with higher activation/arousal, those evaluated at 25 °C were associated more with emotional attributes of negative valence with lower activation/arousal. Notably, since food/beverage-evoked emotions have been found to play a crucial role in consumer liking and choice of selected food/beverage products (Gutjar et al., 2015, Samant and Seo, 2019, Seo et al., 2009), further study should be conducted to determine how sample (or consumption) temperature evokes consumer emotions in other types of foods or beverages.

Examination of previous studies suggests a knowledge gap with respect to associations of sample temperature with sensory or emotional responses to foods or beverages. First, only a few studies have employed both trained and untrained panelists to determine whether perceived attribute intensities differ as a function of sample temperature. Most previous studies related to effects of sample temperature on sensory attribute intensities have used only trained panelists to evaluate intensities of a limited number of attributes with respect to food or beverage samples served at two or three different temperatures: cheese soup (Kähkönen et al., 1995), cooked rice (Yau & Huang, 1996), cheddar cheese (Drake et al., 2005), milk (Francis, Chambers, Kong, Milliken, Jeon, & Schmidt, 2005), wine (Ross & Weller, 2008), and brewed coffee (Adhikari, Chambers, and Koppel, 2019). In recent studies of brewed coffee, trained panelists evaluated sensory attribute intensities of coffee samples at more than three temperatures: four (Chapko & Seo, 2019), six (Steen, Waehrens, Petersen, Münchow, & Bredie, 2017), and seven (Stokes et al., 2016). However, since consumers’ sensory perceptions may differ from those of trained panelists (Kim et al., 2015), both trained and consumer panelists should be studied to fully understand sample temperature effects on sensory attribute intensities in everyday life. Second, only one study has been published thus far with respect to sample temperature-dependent variations in food/beverage-evoked emotions. Although Pramudya and Seo (2018a) showed for the first time that dynamic consumer emotion changes were evoked by green tea or brewed coffee beverages served at three temperatures, there was a lack of information about how emotions would differ over a temperature range of 65 °C to 25 °C. Since consumption of most meals lasts between 10 and 60 min (Bell & Pliner, 2003), people are likely to experience meals initially served hot, over a wider spectrum of temperatures as meals progress (Pramudya & Seo, 2018b). Therefore, it would be worthwhile to track how food/beverage-evoked emotions might change over a wider range of sample temperatures, especially when test samples are typically served at hot temperatures (e.g., soups). Third, while previous research has shown variations in consumer emotions evoked by beverages served at different temperatures (Pramudya & Seo, 2018a), it is still unclear whether or not sample temperature itself, apart from plausible temperature-induced sensory perception, can modulate food/beverage-evoked emotions. This suggests that further study is needed to achieve better understanding of the relationship between sample temperatures and emotions. Finally, in most studies regarding the effects of sample temperature on sensory attributes or food/beverage-evoked emotions, only limited types of samples (e.g., basic taste solutions or beverages) have been used. Therefore, it would be interesting to study how sample temperature effects on sensory and emotional responses exhibit over a wide range of food and beverage samples, and in particularly complex food matrices.

To fill such a knowledge gap, this study was designed to determine whether sample temperatures affect sensory and emotional responses toward food samples, with particular focus on four aspects based on three sub-studies. In Studies 1 and 2, trained and untrained panelists, respectively, were asked to evaluate sensory perception of food samples served at four different temperatures. Consumer panelists were asked to evaluate not only sensory attributes, but also to evaluate emotions evoked by food samples served at different temperatures in Study 2. In Study 3, to determine the sole effect of sample temperature on food/beverage-evoked emotions, water samples served at different temperatures were tested. Tomato soups were chosen as the main target sample because it is among the top 10 food items weekly sold in grocery stores and the U.S. Americans consume more than 10 billion bowls of soup each year (Campbell Soup Company, 2019). Since this popular food is generally served hot, it can provide a good example of a product that undergoes a temperature change that might consequently change its sensory properties. It is also thought that using soup as test sample might help in understanding the influence of temperature on responses to other food items with stronger overall intensities.

Section snippets

Materials and methods

All three studies were conducted in conformance with the Declaration of Helsinki for studies on human subjects. The protocol used in this was approved by the Institutional Review Board of the University of Arkansas (Fayetteville, AR, USA). A written informed consent was obtained from each participant prior to the participation.

Participants

A total of 115 adult volunteers ranging in age from 18 to 59 years were recruited from the Northwest Arkansas community through the consumer profile database of the University of Arkansas Sensory Science Center (Fayetteville, AR, USA). All volunteers self-reported no clinical history of major disease and normal senses of taste and smell. In addition, to minimize any potential temperature-preference influence, volunteers who self-reported extreme liking (9-point on a 9-point hedonic scale) or

Participants

A total of 66 healthy adults (36 females and 30 males) ranging in age from 18 to 65 years (mean age ± SD = 39 ± 13 years) participated in this study. All participants self-reported having normal senses of taste and smell and no clinical history of major disease. In addition, to minimize any potential influence of temperature preference, participants who self-reported extreme liking or extreme disliking of hot or cold beverages were not included. Participants in Study 2 were not recruited for

Discussion

This study was designed to determine whether sensory and emotional attributes of tomato soup might vary with sample temperature. More specifically, this is the first study to systematically approach the effects of sample temperature on sensory attributes detected (qualitative aspect) and attribute intensities (quantitative aspect) from trained (Study 1) and consumer (Study 2) panelists. Using CATA analysis, in Study 2 associations between sample temperatures and emotional attributes were also

Conclusion

This study provided systematic evidence that variations in sample temperature can lead to changes with respect to emotional responses of, along with sensory attributes of, tomato soup samples. Notably, this study suggests that the sample temperature-induced changes in emotional responses to food/beverage samples can also appear in the context of minimizing temperature-induced variations in sensory attributes. Sensory professionals should therefore consider characterizing dynamics in emotional

CRediT authorship contribution statement

Asmita Singh: Conceptualization, Methodology, Formal analysis, Investigation, Writing - original draft, Visualization. Han-Seok Seo: Conceptualization, Methodology, Formal analysis, Resources, Writing - review & editing, Visualization, Supervision, Project administration, Funding acquisition.

Acknowledgement

This study was based upon work that is supported, in part, by the United States Department of Agriculture National Institute of Food and Agriculture Hatch Act funding to H.-S.S.

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