How colour and crunch affect your perception of food

The first bite, as all new cooks are told, is with the eye. Taste and flavour are influenced by colour and vision. And food freshness is all about the crunch.

By Jeremy Ryland


Last week, I discussed Taste and how the flavour of food is affected by a number of factors including temperature, air pressure and texture as well as sound and colour.


It is said that “we eat with our eyes”. What we see “suggests” how food will taste like. So much of what we choose to eat is based on expectations. We look at a piece of chocolate cake and we can almost taste it before we touch it.



Colour is vital in providing an expectation of taste – a ruby red strawberry is going to taste better than a green one. We select our fruit and vegetables on the basis of colour.


People associate certain colours with certain flavours but colour preferences are due to our culture and upbringing. The British like green apples, the Americans light red and the Italians like them deep red.


West Indians buy bananas when they are ripe and brown, whilst we Australians eat them when they are yellow and immature.


Canned peas in France are green-grey; in Britain, they are died green and in Denmark, the water must also be green.


Similarly, some colours put us off. Would you eat a blue steak? What about blue sushi? Of all of the colours of the rainbow, blue is an appetite suppressant. Putting food on blue plates can assist in weight loss! Put a blue light in the fridge and you will probably snack less.


For our early ancestors, blue, purple and black were colour warning signs of potentially lethal food. Blue is associated with mould and “off foods”.


Red has strong associations with flavour. Tomatoes, strawberries and other red fruit and vegetables can often have little flavour but appeal because of their bright red colour.


Golden brown is so appetising that the baking and roasting of bread, cereals, nuts, pastries and roasts are controlled so that they are neither too dark or too light. A pale loaf of bread is not as “appetising” as a golden loaf.


Dark-coloured foods are associated with strong flavours such as sauces, coffee and beer, whilst white signifies refinement and delicacy. Refined white flour, sugar and rice, more costly because of the extra processing, used to be favoured as status symbols rather than the coarse brown unrefined foods of the peasants. In recent times, attitudes have changed with the “peasant” foods becoming trendy, but more white flour, rice, sugar and bread are still sold than brown.


Our response to the colour of food is powerful and determines both perception and taste. Give people a lime drink that is coloured orange and they will think they are drinking orange juice.


And when there is no colour, we have no reference. It is often difficult to correctly identify foods in the dark, although some flavours may be intensified by a lack of visual perception. Some restaurants serve food in the dark or with a blindfold on – so you have to taste the food – not “see” it. When we eat in the dark we often have trouble identifying foods and flavours, and there is a critical element missing in the enjoyment of the cuisine. The colour of food is significant in our selection.


Wine experts can be fooled into thinking a wine is a red wine by adding red dye to white wine. A startling demonstration of how vision influences perception of flavour came from research by Gil Morrot, a French wine expert based in Montpellier.


His team gave volunteers a glass of white wine to sniff. They used "yellow" words such as honey, straw and apricots to describe the smell and correctly identified the wines. Yet when they were offered the same wine coloured with a flavourless red dye, they were confused, immediately reaching for darker imagery such as tobacco, raspberries and tar. When asked to identify the wines, all opted for red grape varieties but had trouble with identification.


However, when the experiment was repeated again - this time with the tasters blindfolded - they were able to identify the wines correctly.


Because the visual clues are so important to our food choice, colours are added to make the food more appealing and more palatable, particularly in foods where the natural colour has been lost due to exposure to light, air, heat and moisture.


Some added colours are natural such as turmeric, annatto, cochineal, beetroot extract, paprika, riboflavin, saffron and caramel. Others are manufactured dyes. The use of colours is very strictly controlled by law and only those considered safe are permitted.


Colours are added to foods to offset colour loss due to light, air, temperature and storage conditions. Colours may be used to mask natural variations in colour and enhance naturally occurring colour. Colour provides identity to foods and protects vitamins from damage by light. And occasionally colour is added for decoration such as in cake icing.


Preservatives can be used to preserve the original colour of the foods. Vegetables are often blanched in hot water to help preserve their colour – especially when being frozen.


Apples, potatoes, etc., when cut will go brown due to oxidation. Rubbing them with lemon juice will stop this, preserving the original colour. The lemon juice contains citric acid which is a natural preservative.


Ascorbic acid (vitamin C) is added to some foods as a preservative – orange juice, for example, will go brown when exposed to light – a small amount of ascorbic acid will preserve its colour


When we choose something to eat, we first look at it - is it the "right" colour? Next, we touch it: is it firm or soft? At the same time, we listen to how it sounds when we break into it: is it crisp and fresh or soggy? Then we sniff it: are there any unpleasant odours? All these impressions tell us what to expect when we put food in our mouths.


So colour is important to the food we choose. But the crunch is also important. Back in September last year, I wrote about the effects of noise on eating and how research has shown that significant levels of background noise can affect the flavour of a meal, reducing a person’s ability to detect salt and sweet foods.



Sound plays a significant part in our flavour perception. When we eat food we actually listen to the crunch – if you cannot hear the crunch of a potato crisp or corn chip, it will taste stale! 


Dr Charles Spence, at Oxford University, asked volunteers to munch on crisps in a booth while they listened to an amplified sound of themselves through headphones. By changing the tone of the crunch as heard through the headphones, Spence fooled the volunteers into thinking the crisps were soggier or crisper than they were.


Heston Blumenthal has exploited our sound perception when he produced a delicate seafood dish called “Sound of the Sea” where he supplies ear pods playing the sounds of the ocean, which intensify the experience of a seafood dish.


And snack manufacturers use packaging that makes rustling, crisp sounds when you open and handle the pack to enhance the crispness of the chips inside!


So next time you consider the flavour of your meal, remember the importance of colour and crunch as well!