Aromas that change flavours

Imagine that you could reduce sugar and retain the sweet taste without sweeteners. It might be possible. As you know, the taste of food depends not only on what the mouth senses but also scents reaching the nose. Can that be used to mask reduced sweetness? Let’s find out

24 November 2020 •

Sales dropped for Campbell Soup Company when they in 2007 reduced the amount of salt in their soups from about 800 mg per serv­ing to as lit­tle as 480 mg in some prod­ucts. To pick up sales, they had to increase the amount of salt again – to 650 grams. A news that caused the share to rise.

There are plen­ty of sim­i­lar sto­ries. Many con­sumers want to eat health­i­er. But not at the expense of taste. This is a dilem­ma that the indus­try is grap­pling with: How do we make food health­i­er with­out los­ing taste. The solu­tion may be in the nose. In any case, there is research that shows that possibility.

Taste, smell, mouthfeel

There are three fac­tors that affect how we expe­ri­ence food: taste, smell and mouthfeel.

Taste. When we put food in our mouths, enzymes in the sali­va begin to break it down, releas­ing flavours that are in the food. Via the sali­va, these flavours get in touch with the taste buds. We have between 5,000 and 10,000 taste recep­tors. They send sig­nals to the brain that make us per­ceive the taste.

Smell. The num­ber of taste recep­tors may sound like a mouth­ful (pun intend­ed), but it is noth­ing com­pared to the 100 mil­lion olfac­to­ry cells in the nose that react when they are reached by dif­fer­ent odor mol­e­cules. They also send sig­nals to the brain.

Mouthfeel. A third fac­tor that affects how we per­ceive food is what we call mouth­feel. It sum­ma­rizes the food’s struc­ture and con­sis­ten­cy but also how the food affects the mouth via heat or cold or oth­er expe­ri­ences such as tick­les from car­bon dioxide.

It is the com­bi­na­tion of taste, smell and mouth­feel that gives us the total experience.

To put in anoth­er way: The taste isn’t in your mouth. Nor is it in your nose. It’s in your brain. That’s where all the sig­nals come togeth­er and form an expe­ri­ence of taste.

Sweet tomatoes

For a long time it was thought that basic tastes, such as sweet and salty, were main­ly per­ceived in the mouth, while the sense of smell played an impor­tant role for more com­plex flavours such as cof­fee and alco­hol. Recent research shows that even sweet and salty are affect­ed by aroma.

A study that showed the impor­tance of the scent for us to expe­ri­ence sweet­ness was done on toma­toes. The researchers test­ed 152 dif­fer­ent types of toma­toes and dis­cov­ered that toma­to vari­eties that con­tained the same sug­ar con­tent could be per­ceived as dif­fer­ent sweet. It was the scent that made some vari­eties feel sweet­er than others.

Another study was done by Robert Sobel, who after read­ing Taste, Aroma, and the Brain decid­ed to inves­ti­gate how scents can ‘trick’ the brain into per­ceiv­ing foods as sweet­er. Among oth­er things, he test­ed vanillin and dis­cov­ered that sub­jects are expe­ri­enc­ing foods that smell vanillin as sweet­er than they actu­al­ly are.

Robert Sobel says that the smells need to be bare­ly notice­able. The brain still per­ceives them and makes them a part of the taste expe­ri­ence. He calls a such scent for phan­tom aro­ma.

Sweet as vanilla

In Denmark, researchers have recent­ly stud­ied which smells make us per­ceive food as sweeter.

They test­ed five dif­fer­ent scents: vanil­la, hon­ey, banana, rasp­ber­ry and elder­flower. Although all five were con­sid­ered sweet in a Danish cul­tur­al con­text, the sub­jects expe­ri­enced two of the aro­mas as sour: rasp­ber­ries and elder­ber­ries. The smell of elder was the one that was per­ceived as least sweet.

The smell of vanil­la, hon­ey, banana was expe­ri­enced as sweet. The smell that was per­ceived as most sweet was vanilla.

The smell of vanil­la made the sub­jects expe­ri­ence the sam­ples as much sweet­er. In fact, sam­ples with a medi­um con­cen­tra­tion of sweet­ness were per­ceived as sweet­er than sam­ples with a high con­cen­tra­tion of sweet­ness, if they came with a vanil­la scent.

kniv som "gröper ur" en vaniljstång

Sweet aromas

Although most peo­ple would do well to con­sume less sweet, salt and fat as most con­sumers are unwill­ing to reduce intake, as it makes the food taste less. When they buy foods with a low­er con­tent of sweet, salt or fat, they often add this when cook­ing, argues Thierry Thomas-Danguin, head of the Centre for Taste and Feeding Behavior in France (CSGA).

His team has devel­oped a method for screen­ing, select­ing and iden­ti­fy­ing odor­ants that are asso­ci­at­ed with taste.

First, they used an olfac­tome­ter to allow a test per­son to smell fruit juice in a con­trolled way. The sub­ject is allowed to describe how sweet, salty, bit­ter and sour they expe­ri­ence the odour. Thereafter, the exper­i­ment is repeat­ed, but now a scent is added by gas chro­matog­ra­phy-olfac­tom­e­try. The sub­jects are allowed to re-describe the expe­ri­ence of the four basic tastes.

In this way, it has been shown that eth­yl butyrate and three oth­er test­ed esters increase the expe­ri­ence of sweet­ness by 20 to 70 percent.

Researchers like Thomas-Danguin believe that sug­ar can be reduced, with no loss in taste, with more than 30 per­cent by just work­ing with odors.

En person som luktar på en apelsin

Way forward

Consumers want to eat health­i­er, but opt out of foods with less salt, sug­ar or fat if the reduc­tion affects the taste experience.

In case of sug­ar reduc­tion, a solu­tion is to add a phan­tom aro­ma that gives a sweet­er expe­ri­ence. For exam­ple, vanillin.

Another solu­tion is to reduce by stealth. Heinz has done that. Without mak­ing much of it, they have grad­u­al­ly reduced added sug­ar by 34 per­cent in their clas­sic toma­to soup. They also grad­u­al­ly reduced the salt in their ketchup by let­ting test pan­els test how much salt they could remove each time. Read more in this col­umn.

If you want to bang the big drum, you can instead do it for what replaces what you reduced – if it is some­thing that con­sumers expe­ri­ence as pos­i­tive. If sug­ar is replaced with sweet­ened fibres, you can empha­size that the food or drink is fiber-enriched instead of boast­ing that it is sugar-reduced.

Or why not do both? Both grad­u­al­ly reduce added sug­ar with­out mak­ing a big deal of it and add phan­tom aro­ma that increas­es the per­ceived sweetness.

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