Belgium: Belgian researchers explain why beer is more bitter when consumed warm

A new study reveals why our taste perception is enhanced as the temperature of food and beverage products increases, explaining why beer is more bitter and ice cream is sweeter when consumed warm, according to the report of 19 December of Foodproduction Europe.

By increasing our understanding of the taste mechanism, the findings could be used to help manufacturers mask bitter, unwanted tastes that often turn consumers off, say researchers in Belgium's Katholieke Universiteit Leuven. The study, published in last week's Nature journal, identified microscopic channels in our taste buds- termed TRPM5- as being responsible for different taste perception at different temperatures.

According to the researchers, the reaction of TRPM5 in our taste buds is much more intense when the temperature of food or fluid is increased, sending a stronger electrical signal to the brain and resulting in an enhanced taste.

“The clearest example for sweet taste is ice cream. As we all know, ice cream does not taste sweet when it is frozen but only when we melt it in the mouth. On the other hand, melted ice cream is very hard to drink because it is extremely sweet,” said the researchers. Interestingly, because ice cream is consumed cold, ice cream makers need to add considerable amounts of sugars or sweeteners in order to endow the product with the much rewarding sweet taste, in detriment of our health,” they added.

The same effect occurs with beverages like beer or wine, in which a bitter taste becomes much more apparent when the products are consumed above the appropriate temperature. On the other hand, consumers enjoy a certain bitter taste in some beverages, such as coffee, tea or cocoa, which is why these taste better when hot.

How consumers sense food is crucial knowledge for a food industry constantly organising the building blocks of new food formulations. And according to lead author Dr Karel Talavera and his colleagues, their findings could allow for the modification of the taste channel in order to achieve required tastes.

“Taste perception could be modulated by adding something to the food that could enhance or inhibit the work of the TRPM5 channel, such as a particular chemical, or by changing the temperature of food,” said Dr Talavera.

“Bitter taste inhibitors could also help fulfill the nutritional requirements of sensitive sectors of the population, such as children.”

“For example, many children do not like salads because of their bitter taste. By understanding the functioning of the TRPM5 channel, certain chemicals could be added to the salad in order to mask our perception of this bitter taste,” he told FoodNavigator.com.

He added, however, that his team of researchers had little knowledge of the family of chemicals that could be used, but suggested their findings serve as a starting point for further investigation.

Previous research into taste has revealed that the human tongue has about 10,000 taste buds with five taste sensations: sweet, bitter, and umami, which work with a signal through a G-protein coupled receptor; salty and sour which work with ion channels.

Contrary to popular understanding, taste is not experienced on different parts of the tongue. Though there are small differences in sensation, which can be measured with highly specific instruments, all taste buds, essentially clusters of 50 to 100 cells, can respond to all types of taste.

Taste buds (or lingual papillae) are small structures on the upper surface of the tongue that provide information about the taste of food being eaten. Indeed, human taste perception is being increasingly examined by scientists in an effort to improve consumers' nutritional intake.

Earlier in 2005, a new $10.9 million (€9m) molecular biology centre in the US- part of Monell's University City facility in Philadelphia- was established in order to better understand taste and smell, and could help the food industry tackle issues such as salt substitution.

An understanding of how human salty taste works is imperative to facilitating the identification of acceptable and practical salt substitutes and enhancers. Using recent advances in molecular genetics, Monell's scientists aim to identify and express genes related to the ENaC receptor subunits believed to be critical to salty taste detection.

"Such knowledge will address important public health concerns by enabling new strategies to reduce salt intake, while also benefiting the food industry's attempts to respond to those concerns," Leslie Stein, science communication officer for Monell Chemical Senses Center had told sister site FoodNavigator-USA.com.

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