Summary: New research suggests ethnicity may influence sensitivity to bitter tastes, possibly linked to anatomical differences on the tongue.
Source: University of Copenhagen
Two studies from the University of Copenhagen report that Danish and Chinese participants differ in sensitivity to bitter tastes, a difference the researchers associate with variations in the distribution of small bumps on the tongue known as fungiform papillae.
Previous research has shown that women often have greater sensitivity to bitter flavors than men. The new studies add evidence that ethnicity may also contribute to variation in bitter taste perception—affecting how people experience foods such as broccoli, Brussels sprouts and dark chocolate.
Researchers tested taste sensitivity using the bitter compound 6-n-propylthiouracil (PROP). Across two complementary studies, Danish and Chinese participants responded differently to PROP, and the researchers linked these differences to anatomical features on the tongue’s surface.
“Our results indicate that most Chinese participants were more sensitive to bitter taste than the Danish participants,” says Professor Wender Bredie from the Department of Food Science (UCPH FOOD). “We also observed a relationship between bitter taste sensitivity and the number of fungiform papillae on the tongue.”
Applying artificial intelligence to count papillae
To quantify papillae reliably and efficiently, researchers from UCPH FOOD collaborated with image-analysis experts in the Department of Computer Science. Using an artificial intelligence–based method, they automated the identification and counting of mushroom-shaped fungiform papillae on tongue images from 152 healthy volunteers—approximately half Danish and half Chinese.
Fungiform papillae, concentrated near the tip and sides of the tongue, contain many taste buds and play a central role in taste perception. The automated approach—built around a tongue coordinate system and image-recognition algorithms—reduces the variability and effort associated with manual counting and allows more precise comparisons of papillae density and distribution across individuals.
The analysis found that Chinese participants generally had a higher density of fungiform papillae than Danish participants, which the researchers suggest may help explain the observed population differences in PROP sensitivity. Professor Bredie cautions, however, that larger and more diverse cohorts are needed before drawing firm conclusions about population-wide phenotypical differences.
Understanding population differences in taste sensitivity has practical implications for food development and consumer preferences. “Producers exporting foods between regions should be aware that consumers in different cultures may perceive the same product differently,” Professor Bredie notes. “This matters when designing flavors and textures for specific markets.”
Differences in texture preferences
In addition to taste sensitivity, the studies examined preferred oral processing behaviors—how people like food to feel and how much chewing they prefer. A clear pattern emerged: most Chinese participants (77%) preferred foods that require little chewing, while most Danish participants (73%) favored firmer foods that need more biting and chewing, such as rye bread and raw carrots.
The reason for these texture preferences is not established by the current studies. The researchers suggest cultural food practices and learned eating behaviors as likely contributors rather than tongue shape. They also observed that participants who preferred firmer textures tended to show greater lingual tactile sensitivity at the tongue tip, although cross-population differences in lingual tactile acuity were not statistically significant.
New automated method for tongue analysis
Counting fungiform papillae manually is time-consuming and prone to error because a tongue can have hundreds of tiny papillae and presentation in images varies. The new AI-based method standardizes tongue images by mapping them into a tongue-coordinate system. This approach minimizes visual distortions caused by tongue posture (narrowing, widening, bending) and provides a consistent basis for estimating papillae density and other spatial features across participants.
Study details
- Participants: 152 healthy non-smokers, ages 18–55 (75 Danish, 77 Chinese). The cohort included 71% women and 29% men.
- Taste testing: Sensitivity to bitter taste was evaluated using 6-n-propylthiouracil (PROP), a compound commonly used as a marker of genetic variation in taste perception.
- Research team: Jing Liu and Wender Bredie (Department of Food Science); Chenhao Wang and Jon Sporring (Department of Computer Science); Camilla Cattaneo and Ella Pagliarini (University of Milan); Anne C. Bech (Arla Innovation Centre). Funding and support came from Arla Foods amba and the Capital Region of Denmark.
Abstract (summary)
Fungiform papillae are prominent protrusions on the tongue containing taste buds and are concentrated toward the tip and sides. The studies introduce a standardized tongue-coordinate system and an automated image-analysis pipeline to estimate papillae density and distribution, reducing variability introduced by tongue posture in photographs. Using data from 152 participants, the research explores links between fungiform papillae density, PROP responsiveness, gender, ethnicity, and preferred oral processing behaviors. Results indicate cross-cultural differences: Chinese participants showed higher papillae density and greater PROP responsiveness than Danish participants, and texture preferences diverged between the groups. The findings suggest potential relationships between tongue anatomy, taste sensitivity, and oral processing preferences, but larger studies are required to confirm these patterns.
About this press release
Source: University of Copenhagen. Contact: Press Office – University of Copenhagen. Image: public domain.