Did you know that taste was discovered long before birth?Acid,bitter, salty, sweet andumami (or the 5th flavour, meaning "delicious" in Japanese) cause a set offacial expressions. These are gusto-facial reflexes! These mimics are different for each flavour, but they are identical for the same flavour from one individual to another. I will tell you more about them in this article!
Let's start from the beginning! The gustatory system gradually develops in-utero. From 10 weeks of pregnancy, taste buds and papillae appear. The foetus therefore begins to perceive the different flavours of the amniotic fluid. The maturation of this taste system continues until mid-childhood.
After birth, reactions to sweet and umami are usually interpreted as positive pleasure reactions. Bitter and acidic stimuli trigger reactions that are considered negative. The response to saltiness is less characteristic.
THE SWEET TASTE
It causes the corners of the mouth to contract and the lips to thin. The sweet taste is frequently accompanied by relaxation of the facial muscles and licking of the lips. This produces a reaction similar to a smile. This reflex is followed by a strong sucking action.
THE BITTER TASTE
This stimulation triggers lowering of the mouth angles and opening, blinking, flattening and protrusion of the tongue out of the mouth, head movements, heavy salivation and delayed sucking. These reactions are interpreted as anger or displeasure.
THE ACIDIC TASTE
A similar but attenuated response is observed with acidic stimulation: lowering of the corners of the mouth, opening of the mouth, prolonged pursing of the lips, wrinkling of the nose and blinking of the eyelids. As with bitterness, these reactions are generally considered negative. Salivation is increased after acid stimulation.
THE SALTY TASTE
Salt solution, on the other hand, causes a repulsive response with the eyes and nose wrinkling and the mouth twisting slightly. Responses to salty stimulation are more variable.
As anaside, from a sensory point of view, food is characterised by its texture, appearance and flavour. The latter is often cited as the primary reason for liking or rejecting a food, with texture coming second.
Overall, the attraction to sweetness and the rejection of bitterness and acidity increases in childhood and decreases in adulthood. All the gusto-facial reactions and reflexes described above towards flavours are innate or reflexive. However, the development of taste perceptions is partly done throughexperience orlearning. The acquired will outweigh the innate! So again, let your child taste as many foods as possible to create their own food repertoire!
Dietician - Nutritionist specialising in paediatrics
Sources: BELLISLE F. Food behaviour and sweet taste. Pratiques en nutrition, January-March 2017, volume 13, number 49, pages 22-25
NICKLAUS S. Taste perceptions in children. Archives of Pediatrics, May 2005, volume 12, number 5, pages 579-584
FAVRE E. Taste education and food diversification. University Diploma "Specialisation in child and adolescent dietetics", Faculty of Nancy, November 2019
