Summary: Ethnicity may play a role in the perception of bitter tastes, a new study reports. Researchers say this could be related to anatomical differences on the surface of the tongue.
Source: University of Copenhagen
Two studies from the University of Copenhagen show that Danes aren’t quite as good as Chinese at discerning bitter tastes. The research suggests that this is related to anatomical differences upon the tongues of Danish and Chinese people.
For several years, researchers have known that women are generally better than men at tasting bitter flavours. Now, research from the University of Copenhagen suggests that ethnicity may also play a role in how sensitive a person is to the bitter taste found in for example broccoli, Brussels sprouts and dark chocolate.
By letting test subjects taste the bitter substance PROP, two studies demonstrate that Danish and Chinese people experience this basic taste differently. The reason seems to be related to an anatomical difference upon the tongue surfaces of these two groups.
“Our studies show that the vast majority of Chinese test subjects are more sensitive to bitter tastes than the Danish subjects. We also see a link between the prominence of bitter taste and the number of small bumps, known as papillae, on a person’s tongue,” says Professor Wender Bredie of the University of Copenhagen’s Department of Food Science (UCPH FOOD).
A taste of artificial intelligence
Using a new artificial intelligence method, researchers from UCPH FOOD, in collaboration with Chenhao Wang and Jon Sporring of UCPH’s Department of Computer Science, analysed the number of mushroom-shaped “fungiform” papillae on the tongues of 152 test subjects, of whom half were Danish and half Chinese.
Fungiform papillae, located at the tip of the tongue, are known to contain a large portion of our taste buds and play a central role in our food and taste experiences. To appreciate the significance of papillae in food preferences across cultures and ethnicities, it is important to learn more about their distribution, size and quantity.
The analysis demonstrated that the Chinese test subjects generally had more of these papillae than the Danish subjects, a result that the researchers believe explains why Chinese people are better at tasting bitter flavours.
However, Professor Bredie emphasizes that larger cohorts need to be examined before any definitive conclusions can be drawn about whether these apparent phenotypical differences between Danes and Chinese hold at the general population level.
More knowledge about differences in taste impressions can be important for food development. According to Professor Bredie:
“It is relevant for Danish food producers exporting to Asia to know that Asian and Danish consumers probably experience tastes from the same product differently. This must be taken into account when developing products.”
Danes prefer foods that require a good chew
Professor Wender Bredie points out that genetics are only one of several factors that influence how we experience food. Another significant factor has to do with our preferences — including texture. Think, for example, of the difference between munching on crispy potato chips from a newly opened bag, compared to eating softened ones from a bag opened the day before. Here, many Danes would probably prefer the crispy ones over the soft ones, even if the taste is similar. According to the UCPH studies, there seems to be a difference between the Danish and Chinese test subjects on this point as well.
While the vast majority of Chinese subjects (77%) prefer foods that don’t require much chewing, the opposite holds true for the Danish subjects. Among the Danes, 73% prefer eating foods with a harder consistency that require biting and chewing — rye bread and carrots, for example.
The reason for this difference remains unknown, but the researchers suspect that it stems from differences in food culture and the ways in which we learn to eat. The studies do not point to tongue shape as making any difference.
THE NEW METHOD
Because the counting of tongue papillae is usually done manually, and a tongue has hundreds of tiny fungiform papillae, it is a demanding job in which mistakes are easily made.
The new method, based on artificial intelligence and developed by image analysis experts Chenhao Wang and Jon Sporring of the Department of Computer Science, automates the counting and delivers precision. Using an algorithm, they have designed a tongue-coordinate system (see figure) that can map papillae on individual tongues using image recognition.
ABOUT THE RESEARCH:
The 152 study participants were all healthy non-smokers between the ages of 18 and 55. Of them, 75 were from Denmark and 77 from China. 71% of participants were women and 29% men.
Test subject sensitivity to bitter taste was examined by allowing subjects to taste the bitter substance 6-n-propylthiouracil (PROP), considered a genetic marker for differences in taste perception.
The research was conducted by: Jing Liu and Wender Bredie from the Department of Food Science; Chenhao Wang and Jon Sporring from the Department of Computer Science; Camilla Cataneo and Ella Pagliarini from the University of Milan; and Anne C. Bech from Arla Innovation Centre. The research received support from Arla Foods amba and the Capital Region of Denmark.
About this taste perception research news
Source: University of Copenhagen Contact: Press Office – University of Copenhagen Image: The image is in the public domain
A Novel Approach to Tongue Standardization and Feature Extraction
Fungiform papillae are large protrusions on the human tongue and contain many taste-buds. Most are found on the tip and the sides of the tongue, and their distribution varies from person to person. In this paper, we introduce a tongue-based coordinate system to investigate the density and other features of fungiform papillae on the surface of the tongue. A traditional method for estimating the density of fungiform papillae is to count the papillae in either a manually selected area or a predefined grid of areas on the tongue. However, depending on how a person presents his or her tongue in a specific image (such as narrowing, widening, and bending), this can cause visual variations in both the papillae’s apparent positions and apparent shapes, which in turn also affects the counts obtained within an area. By transforming the individual tongues into a standardized tongue, our tongue coordinate system minimizes these variations more effectively than current alignment-based methods. We further hypothesize an underlying fungiform papillae distribution for each tongue, which we estimate and use to perform statistical analysis on the different tongue categories. For this, we consider a cohort of 152 persons and the following variables: gender, ethnicity, ability to taste 6-n-propylthiouracil, and texture preference. Our results indicate possible new relations between the distribution of fungiform papillae and some of the aforementioned variables.
Cross-cultural differences in lingual tactile acuity, taste sensitivity phenotypical markers, and preferred oral processing behaviors
Cultural and genetic differences in consumer populations across the world are important determinants for food preferences. The present study investigated differences in preferred oral processing behaviors between Chinese Asian and Danish Caucasian consumers and the possible relationship to lingual tactile acuity and the two most well-researched phenotypic markers of taste sensitivity, such as 6-n-propylthiouracil (PROP) responsiveness and Fungiform Papillae Density (FPD).
A total of 152 consumers (75 Chinese, 77 Danish) were enrolled in the study and categorized by their preferred oral processing behaviors. Lingual tactile acuity was assessed according to responses to stimulation with von Frey filaments. The responsiveness to PROP and the FPD were also determined.
Cross-population differences were found in preferred food oral processing behaviors in these two cohorts, as Chinese consumers were characterized by a larger number of ‘Soft processing likers’ (77% of the population) who preferred soft food processing in the mouth. Contrarily, Danish consumers mostly belonged to the ‘Firm processing likers’ group (73% of the population) who had preferences for foods that needed firm processing on biting and chewing. Moreover, the group of ‘Firm processing likers’ appeared to be more sensitive to touch at the apex of the tongue compared with the ‘Soft processing likers’ in both population cohorts. Cross-population differences in lingual tactile acuity were not significant. Differences in FPD and PROP responsiveness were found between these two population cohorts, with Chinese consumers generally characterized by greater FPD and PROP responsiveness compared with the Danish subjects.
This study provides evidence on cross-cultural differences in preferred oral processing behaviors and in the two phenotypic marker of taste sensitivity. However, further studies are needed to draw conclusive relationships between preferred oral processing behavior and oral tactile acuity, PROP responsiveness and tongue anatomy.