10 scientific facts about flavour

As a learned journal brings together research findings about how we taste, Clint Witchalls looks at what scientists have discovered so far.

view gallery VIEW GALLERY

Taste is fairly well understood. It is detected by the tongue and is neatly categorised into sweet, bitter, sour, salty and umami. If food was only experienced as taste, chefs and restaurant critics would be out of a job. Luckily, taste is only one facet of the complex thing we call flavour.

Flavour is, of course, the stock in trade of chefs. For centuries, they have been combining flavours to create something that is more than the sum of its parts. From a scientific point of view, however, flavour is not that well understood. Although there has been a drip-feed of research over the years, there has been no cohesive effort to study flavour as a discipline.

That has just changed. BioMed Central, publishers of open access science journals, launched a new title last month: Flavour. For the first time, there will be a forum for flavour research, whether you're a biologist, a chemist, a neuroscientist, a psychologist, an anthropologist or even a philosopher. Unlike most science journals, which are aimed at a narrow group of specialists and are all but indecipherable to everyone else, Flavour hopes to appeal to a much broader church, including chefs.

Before the research starts pouring in, here is a quick run down of some of the things scientists know about flavour.

'Flavour' is published by BioMed Central (biomedcentral.com)

1. Flavour is evolution's way of making sure we eat a varied diet

This is because we need certain nutrients in order to survive. "There needs to be ways of guiding us through to ensure we get enough of these macro and micro nutrients," says Per Moller, editor-in-chief of Flavour. "Nature solves that problem by endowing us with the ability to sense flavours of food."

Different macronutrients tend to have different flavours. Bread and potatoes and pasta are more similar than different meats are. "If you eat potatoes, after a couple of hundred grams you won't like the potatoes quite as much as you did when you started eating them," says Moller. "So there is a decline in the liking of the thing you have eaten a bit of, but without a decline in liking of other foodstuffs." Or, in science-speak, we possess neuro-biological systems that are sensory-specific satiety mechanisms. "Luckily, we don't need a degree in nutritional science to get a balanced diet," quips Moller.

2. We don't just sense flavour with our tongues

Taste, smell, touch, sight, sound, temperature, trigeminality (the irritating component of odour, as experienced when eating a chilli or horseradish), and interoception (stimuli arising inside the body) are all involved in creating the sensation in our brains that we call flavour.

3. Colour affects how we perceive flavour

Red wines are usually described in terms of red or dark objects and white wines in terms of light or yellow objects. The Independent on Sunday's wine expert, Terry Kirby, described Sequillo 2008, a blended white wine, as tasting of "straw, nuts and honey", and Lirac Clos de Sixte 2006, a blended red, as tasting of "spices, dark chocolate and black fruits". Had those wines been decanted into opaque glasses, even Kirby might have described the flavours differently. Researchers at the School of Enology at Bordeaux University found that when students were given white wine, tinted red with a flavourless additive, and asked to describe it, they tended to use adjectives usually reserved for red wines.

4. Coffee tastes worse in a flimsy cup than a substantial one

Researchers at Rutgers University and University of Michigan found that the firmness of a cup influences people's perceptions of taste and quality. Give them the same beverage in a firm cup and they will prefer the taste to the beverage in a flimsy cup. The subjects were also divided into groups who like to touch things before they buy them (high autoletics) and people who don't like to touch before they buy (low autoletics). Oddly, the people who touch everything when out shopping are least influenced by touch in taste evaluations.

5. Even how food is described can affect its flavour

Protein bars taste less good if they are described as soy protein and yoghurt, and ice-cream is perceived to be more flavoursome when described as full fat or high fat.

6. There is no such thing as a 'tongue map'

The human tongue does not have distinct zones for discerning sweet, bitter, sour, salty and savoury tastes. The so called "tongue map", often seen in primary school textbooks, is based on dodgy research published in 1901 by a German scientist named DP Hanig. Despite the science being debunked back in 1974, some wine-glass makers still make spurious claims that this or that shaped glass will draw wine to a specific part of the tongue. Taste buds actually have 50 to 100 receptors for each taste, including umami (the taste of glutamate).

7. Some people have many more tastebuds than the rest of us

They are called super-tasters. That doesn't mean they're connoisseurs, it means they're very sensitive to bitter tastes. Do you hate the taste of Brussels sprouts? You may be a super-taster.

8. Although it's yet to be utilised, the smell of food matters

Aroma is an extremely important component of flavour and it is detected by receptors in the nose (orthonasal) and the mouth (retronasal). You might think that the brain treats both of these signals the same, but scientists have found, using fMRI brain scans, that different parts of the brain are stimulated depending on whether the aroma is detected by the nose or the mouth. What this means for chefs, though, is not clear yet.

9. Aroma affects the amount of food we put in our mouths

Scientists in the Netherlands developed an experiment where a "custard-like dessert" was fed to volunteers while different scents were presented to their noses. The research, published in the inaugural issue of Flavour, reported that strong aromas lead to smaller bites, suggesting that aroma could be used to control portion size. Forget the fat tax, what we really need are strongly flavoured fast foods.

10. Our liking for flavours develops before birth

A recent study took 24 pregnant women and divided them into two groups. One group was given a diet containing anise, and the second group was given an anise-free diet. Shortly after the babies were born, they were presented with cotton soaked in anise. The babies whose mothers had consumed anise during their pregnancy showed no aversion to the swab, while the babies whose mothers had avoided anise showed a strong aversion to the aroma.

Unanswered questions

One thing science hasn't answered yet is why some flavour combinations work while others don't. One theory is that there is a chemical overlap between flavours that work well together. Heston Blumenthal's unlikely combination of white chocolate and caviar is said to work well because both ingredients contain trimethylamine.

But, it turns out the flavour-sharing hypothesis doesn't have legs. Yong-Yeol Ahn, of Harvard University, and colleagues did a statistical analysis of 56,000 recipes from various regions and found that, indeed, there is a tendency in North American and Western European cuisine to use ingredients that share many flavour compounds.

However, the researchers found that Southern European and East Asian cuisines tend to avoid compound-sharing ingredients, yet few would argue that these regions don't produce delicious food. So we're still none the wiser as to why we like certain food combinations and not others.

But if food is essential to our survival, why did evolution endow us with a dislike for, say, strawberries and liver? Scientists, please send your answers to Mr Moller.

Independent Comment
blog comments powered by Disqus
News in pictures
World news in pictures
Life & Style blogs

Million pound investment to bring Liverpool homes back into use

Dozens of empty homes in two of Liverpool’s most deprived areas will be brought back into use thanks...

Building blocks

A roundup of the latest property news

London renters are getting poorer and moving further out

Plus, do energy saving measures boost house prices?

       
 

ES Rentals

    iJobs Job Widget
    iJobs Food & Drink

    Graduate Trainee Opportunity – Executive Recruitment

    £20,000 - £45,000 OTE: Co-Venture: Working on international markets without ge...

    Graduate Trainee – Recruitment Consultant

    £20,000 - £45,000 OTE: Co-Venture: Working for this company will give you a ch...

    Associate/Director of Transport

    £40000 - £60000 Per Annum: The Green Recruitment Company: The Green Recruitmen...

    Travel Sales Consultant

    £18000 - £35000 per annum + Award-Winning Benefits & Uncapped Comm: Flight Cen...

    Day In a Page

    Babies behind bars: A Palestinian fertility doctor has become an unlikely hero by helping women conceive – even though their husbands are in jail

    Babies behind bars

    A Palestinian fertility doctor has become an unlikely hero by helping women conceive – even though their husbands are in jail
    Sonic youth: The high-pitched sound alarm for under 25s

    Sonic youth: The high-pitched sound alarm

    Is Mosquito, the alarm only under-25s can hear, a blessing or a bane?
    The art of living in small spaces: Architects are learning how to make less, more

    The art of living in small spaces

    Space in cities at a premium so architects are learning how to make less, more...
    Special report: The story of Sir Mervyn King's reign at the Bank

    The story of Sir Mervyn King's reign at the Bank

    After four 'nice' years as Governor of Bank of England, things turned decisively nasty
    Zombie nation: Our enduring fascination with a world full of death and destruction

    Zombie nation: Our fascination with death and destruction

    A new season of shows on Radio 4 is inspired by dark tales of future dystopias. Meanwhile, zombies are marauding in the multiplexes...
    Martin Stephen: 'Ofsted says comprehensives are failing the most able but teaching bright children isn't rocket science'

    'Teaching bright children isn't rocket science'

    It doesn't take a selective system to nurture the best minds, says a former head of St Paul's boys' school.
    The retail empires strike back: Can new technology lure us back to the high street?

    Can technology lure us back to the high street?

    The high street has been bruised and battered by online firms but in-store technology is helping to enliven the retail experience...
    The 10 Best new smartphones

    The 10 Best new smartphones

    Photos, films, music, apps and browsing - the latest mobiles can do it all
    Jenson Button: Downbeat driver cannot wait to put season behind him

    Jenson Button: Downbeat driver cannot wait to put season behind him

    McLaren man admits 'failed gamble' with car has left him pinning hopes on 2014 campaign
    James Lawton: Firmer fist will be required to win Champions Trophy final battle with stouter foe

    James Lawton

    Firmer fist will be required to win Champions Trophy final battle with stouter foe
    'To farm I have to rape the countryside. It’s got to be wrong': The true effect of the badger cull

    The true effect of the badger cull

    'To farm I have to rape the countryside. It’s got to be wrong'
    Theatre review: Daniel Radcliffe gives an admirably honest performance in Michael Grandage's The Cripple of Inishmaan

    First night: The Cripple of Inishmaan

    Daniel Radcliffe gives an admirably honest performance in Michael Grandage's comedy
    Girls Guides drop religious reference but pledge to self and the Queen

    Guides drop religious reference but pledge to self and the Queen

    After 103 years, organisation changes oath to welcome 'all girls, of all faiths, and none'
    Steve Tongue: Joe Kinnear was one of the boys and a breath of fresh air... 21 years ago

    Steve Tongue

    Joe Kinnear was one of the boys and a breath of fresh air... 21 years ago
    Chris Froome: Free from 'pain in neck' after Bradley Wiggins' exit

    Chris Froome: Free from 'pain in neck' after Wiggins' exit

    Sky's lead rider says he is in fantastic form for the Tour and happy pecking order debate is over