Australian_Geographic_-_December_2015_AU_

November–December 2015 17

ILLUSTRATION BY ZOE LAWRENCE; TEXT AND RESEARCH BY MADELEINE VAN DER LINDEN

TOPOGR APHICAL

Accounting

for taste

The centre of the

tongue has few

tastebuds and is the

least sensitive to taste.

TONGUE

Palatine tonsil – tonsils Lingual tonsil

are masses of lymphoid

tissue that have a role

in the immune system.

Epiglottis – this directs

food into the esopha-

gus and away from the

trachea; it also has

tastebuds on it.

Circumvallate papil-

lae are at the back

of the tongue and

shaped in circles.

Fungiform papillae

on front of tongue.

Foliate papillae are

in ridges/grooves

towards the back

and sides of tongue.

Filiform papillae

are mostly on the

sides of tongue.

We each have up

to 10,000 tastebuds

on our tongue

“I

SN’T SHE SWEET”, “bitter old

man”, “He’s a good salt.” English is

littered with sayings relating to our

sense of taste. It’s one of the earliest senses,

developing 21 weeks after conception, and

is also one of the most powerful. There are

fi ve basic tastes: sweet; sour; salty; bitter;

and savoury, or umami (and perhaps now

a sixth – fat). The historic diagram that

shows the tongue divided into diff erent

regions responsible for each taste is in

fact a myth. All tastebuds detect all

fl avours, but the concentrations of cells

able to detect diff erent chemicals (sodium

chloride for salty, sucrose for sweet, for

example) varies across the tongue,

meaning that some fl avours appear

to be detected in diff erent regions fi rst.

SPICY

The ‘fl avours’ of hot

and spicy in chilli and

pepper are sensa-

tions, not tastes. The

chemical capsaicin

stimulates pain recep-

tors, producing the

impression of heat.

BABIES

Babies are born with

tastebuds not only on

their tongue, but all

over their mouth.

The tongue is covered with sensory

structures called papillae, which are

packed with hundreds of tastebuds and

come in a variety of types and shapes.

PAPILLAE

CORIANDER

Some people hate the

taste of coriander, but

it’s actually the smell

they don’t like.

Roughly 80% of

what we perceive to

be taste is actually

smell. When it comes

to coriander, some

people only smell the

bitter chemicals in the

herb, creating a nasty

taste in the mouth.

TASTEBUD

Tastebuds each contain separate cells that

pick out the fi ve different fl avours and their

levels of intensity as they wash over the

tongue in saliva. Each individual tastebud

only lives for about 10 days.

BITTER

Our dislike of bitter

tastes was developed

to stop us eating

poisons. Pregnant

women have a

heightened ability to

taste bitter things in

order to protect them

and the baby from

toxins. Breast milk has

a bitter inhibitor to

ensure that the baby

will drink it.

SUPERTASTERS?

Some people have a

greater concentration of

tastebuds, making them

‘supertasters’. They are

sensitive to bitter fl avours

from foods such as coffee

or broccoli and are more

likely to be fussy eaters –

although some scientists

have now contested the

supertaster theory.

UMAMI

Umami – also

known as ‘savoury’ –

is the fl avour of MSG,

glutamic acid or

aspartic acid and is

thought to be linked

to the overall protein

content of food.

Filiform papillae

Circumvallate papillae

There are still many chemi-

cal receptors on taste cells

that scientists don’t under-

stand. We may soon fi nd

taste receptors for sub-

stances such as fat, carbo-

hydrate, phosphorus and

calcium, says Professor

Russell Keast at Deakin

University in Melbourne.

NEW FLAVOURS