The cause of dark chocolate’s mouth-watering smell has finally been discovered as scientists pinpoint the exact chemicals responsible for the aroma.
A host of chemicals, including one which also gives roses their unique fragrance, is the guilty party, according to a new study.
Roasted cocoa beans are rich in beta-ionone, also found in perfume and essential oils, which contributes to its scent.
The breakthrough explains why the smell of chocolate is so alluring – and could lead to even tastier snacks being custom made in future, suggests the research.
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Roasted cocoa beans are rich in beta-ionone – found in perfume and essential oils, say scientists. The breakthrough explains why chocolate is so alluring – and could lead to even tastier snack bars, suggests the research (stock)
Now a German team has identified the substances that make up this heavenly aroma – opening the door to unique ‘designer chocolates’.
They bought two types of dark chocolate, each with a distinctive aroma, from a local shop.
Chemicals within the smell of chocolate were analysed using a technique called extract and stable isotope dilution analyses.
it found various volatile compounds are directly involved responsible for the smell.
These are chemicals that transform into gases easily at room temperature – and are inhaled along with the air we breathe.
That brings them into contact with more than 900 receptors in the upper half of the nostril – making us crave chocolate.
Some, such as beta-ionone, have never been identified in chocolate before.
Using the data, the researchers then reconstructed the aromas of both chocolate varieties. These smelled very similar to the original bars, a trained sensory panel decided.
The findings, published in the Journal of Agricultural and Food Chemistry, may help manufacturers control and improve the flavour of chocolate bars.
Dr Carolin Seyfried, of the Technical University of Munich, said: ‘Chocolate is one of the most-consumed treats around the world.
‘Flavour is more than just what the tongue tastes – smell also plays a key role, with many compounds working together to create a unique sensory experience.
‘Although nearly 600 compounds have been identified in chocolate over the last century, only a fraction of them are known to contribute to the aroma.’
Previous studies have identified compounds responsible for the scent of milk and dark chocolates.
But it has been unclear how much of each component is needed to make something smell specifically like dark chocolate.
So Dr Seyfried and co author Dr Michael Granvogl decided to build the scent from scratch for the first time.
They said: ‘In summary, this study is the ﬁrst to successfully characterise the key aroma compounds in dark chocolate.
‘Owing to its production with fermentation and roasting steps, the aroma of chocolate and cocoa products is very complex, containing a relatively high number of odorants, and thus more than 25 compounds were needed to simulate the overall aroma.’
The researchers were funded by the Research Association of the German Food Industry through the German Federal Ministry of Economic Affairs and Energy.
The smell alone is usually enough to evoke strong cravings from even the most disciplined eaters. Much like a fine wine, high quality chocolate has a multi layered scent and flavour with notes of vanilla, banana or vinegar (stock)
IS CHOCOLATE GOOD FOR YOU?
Chocolate is undoubtedly the nation’s favourite dietary vice but lots of research over the years has found that it could actually be good for us.
With more than 300 chemicals in chocolate, scientists are investigating a whole range of health benefits linked to the food.
Researchers at Harvard University studied 8,000 men aged over 65 and found that those who ate modest amounts of chocolate lived almost a year longer than those who ate none.
Dr Neil Martin of the Cognition and Research Centre at Middlesex University exposed people to different smells and measured their brain activity.
The results showed that smell receptors in the nasal passages reacted so strongly to the chemical mix in chocolate that it left people on an emotional high.
A 100g bar of dark chocolate gives you 2.4mg of iron and 90mg of magnesium, around one third of the recommended daily amounts.
White chocolate, on the other hand, contains no cocoa solids, just cocoa butter, and is relatively high in fat. A 100g white Toblerone bar has a whopping 540 calories and 30.7g of fat.
Yet, despite its sugar content, chocolate is said by dentists to be less damaging to the teeth than many other sweets because it tends to be chewed quickly, not sucked.
There are also naturally-occurring tannins in chocolate that help to inhibit the growth of dental plaque.
And there is known to be a substance in all chocolate called phenylethamine (PEA), which is produced naturally by the brain and thought to increase levels of the mood-enhancing chemicals, serotonin and endorphins.
In theory, the more PEA you eat, the more amorous and aroused you feel, which is why chocolate has gained a reputation as an aphrodisiac.
A TV series on the Food Network called Food: Fact or Fiction? looks at how eating chocolate affects the brain.
Researchers found sharing chocolate with a loved one increased oxytocin levels.
This much-loved sweet treat also stimulates theobromine and phenylethylamine.
Phenylethylamine stimulates the release of B-endorphin which stokes the production of dopamine and norepinephrine.
These chemicals flood your system when you’re feeling loving.
Theobromine is chemically similar to caffeine and like its chemical cousin it stimulates the central nervous system and also has mood enhancing effects.
An earlier study by the same group found the aroma of roasted cocoa beans – the key ingredient for chocolate – emerges from a host of substances.
Individually these smell like potato chips, cooked meat, peaches, raw beef fat, cooked cabbage, human sweat, earth, cucumber and honey.
Chocolate pioneer Professor Peter Schieberle, who runs the lab, says: ‘To develop better chocolate, you need to know the chemistry behind the aroma and taste substances in cocoa and other ingredients.
‘That understanding must begin with the flavor substances in the raw cocoa bean, extend through all the processing steps and continue as the consumer eats the chocolate.
‘When you put chocolate in your mouth, a chemical reaction happens. Some people just bite and swallow chocolate. If you do that, the reaction doesn’t have time to happen, and you lose a lot of flavour.’
Chocolate is made from cocoa beans, the seeds of the cacao tree. But they have to be processed to bring out their characteristic flavour.
This starts with fermentation, in which the moist seeds sit for days in baskets covered with banana leaves while yeasts and bacteria grow on the beans and alter their nature.
The beans are dried in the sun and then roasted. Worldwide, about 3 million tons of cocoa are produced each year.
Cocoa production developed over the years by trial and error, not by scientific analysis, so the substances that give chocolate its subtle flavours were largely unknown.
Over the past three decades Professor Schieberle’s team has uncovered many secrets of chocolate’s allure.