SENSORY EVALUATION of FOOD

Why we eat?

Hunger Fuel our bodies Psychological ( emotional

eating) Boredom

Nutrient--

“to nourish” Chemicals the body

needs to function, grow, repair itself and creates energy.

Basic Nutrients

Proteins Carbohydrates Fats Vitamins Minerals Water

Influences on our food choices Culture Geography Psychology and

emotions Beliefs and religion Health concerns Costs Social, friends Advertising, current

food trends

Technology Likes and dislikes Special occasions

We taste with all of our senses. our flavor perception is actually

determined by the: Smell Taste Appearance sound

Texture play a big role in our appreciation of foodstuffs:

just think how unappealing food tastes when it is accidentally served at the wrong temperature (such as food served cold, when it should be hot or vice versa).

'Superadditive' personalities The human brain actually

combines the information from each of our senses according to a number of very specific rules.

So, for example, our brains tend to combine weak signals (such as the combination of a very weak taste with a very faint odour) in a 'superadditive' way that gives rise to a perception of flavour.

Sensory cues If you get the combination of

sensory cues wrong then the brain will not be impressed and it will give a subadditive response.

That is, a response that is far lower than would have been elicited by either of the sensory triggers had they been presented in isolation.

Example: Combining the taste of strawberry with the 'incongruent' smell of a savoury chicken soup

Where you grew up matters to your brain!

The combinations (smell and taste) that the brain will put together in a superadditive manner will depend upon where you grew up.

So, for example, those people who have grown up in the UK, experienced the combination of a sweet taste together with the smell of almond in their diet, will tend to integrate the smell of almond and the sweet taste of sugar in a superadditive manner.

The brain of someone who has grown up in Japan will not integrate sugar and almond in a superadditive manner (since they will not have come across that particular combination of taste and smell in Japanese cuisine).

Instead, Japanese people show a superadditive response to the smell of almond when it has been paired with a salty taste (since that combination of smell and taste is common in Japanese cuisine, especially in things like pickled condiments).

Thus, brain science is beginning to help explain why it is that what tastes so pleasant to the people from one country can taste so bad to someone who has been brought up in another country.

The stronger sense of eating Another important rule that psychologists and

brain-scientists have discovered about how the human brain combines the signals reaching each of the senses is known as 'sensory dominance'.

That is, our brains use the most accurate of our senses when trying to figure out what is out there in the world around us, and this 'cognitive short-cut' even applies when we are trying to decide what exactly it is that we are eating and/or drinking.

Our sight is generally very accurate in terms of being able to tell us what something is.

Our perceptions tend to be dominated by what our brains see, rather than by what they smell or taste or feel, etc.

An example of the visual dominance over flavour perception comes from researchers in Bordeaux, France.

People (even trained wine tasters) were fooled into thinking that they are drinking a glass of red wine simply by colouring white wine red using an odourless food dye.

The people (more than 50 people enrolled on a university wine course) perceived the white wine as having the bouquet of a red wine when it was coloured red.

Hearing things Our perception of food is also determined by

the sound it makes as we eat or drink it. In a study, people's perception of the

freshness and crispiness of potato crisps could be changed simply by altering the sounds that people heard when they bit into the chips.

In particular, whenever the high frequency components of the crisp-biting sounds were boosted, people would judge the crisps as being both fresher and crisper.

A microphone was placed by peoples' mouths so the crisp biting sounds were picked up and were fed back to the participants ears through a pair of headphones.

Our brains are continuously monitoring the signals going into our ears, and using them in order to help determine what exactly it is we are eating or drinking and just how much we like it.

We don't often pay much attention to the subtle sounds that we make whenever we eat and drink.

Research has been able to show that people's perception of the flavour of food can also be influenced by the sounds (or music) that is played in the background environment while they are eating.

So, for example, in one recent experiment, people were given two scoops of bacon and egg ice cream, one after the other.

They had to rate the relative strength of the bacon flavour versus the egg flavour in each scoop. It was found that

when the people heard the sound of farmyard chickens squawking, then the ice cream tasted much 'eggier‘.

When sizzling frying bacon sounds were played over the loudspeaker system, people really thought that the ice cream had a much more prominent bacon taste.

The incorporation of the multisensory cues in the environment into our perception of the food and drink that we are consuming might then help to explain why so many of us have had the experience of buying a cheap bottle of great-tasting wine on holiday in the Mediterranean, only to find that when we get it home and open it in front of our friends that it suddenly tastes awful.

What happened?

Well, while on holiday your brain

was taking in all those pleasant environmental cues such as the smell of the salty sea air, the warmth of the sun on your skin and the sound of the waves crashing on the beach and none of those environmental cues are present when you try the wine back in your own living room, it no longer tastes as good.

SENSES

Flavor – is the distinctive quality that comes from food’s blend of

Appearance Taste Smell, odor Feel, texture Sound

Taste Taste-buds: sensory organs located on the tongue- cells

lining the surface have pores that are activated with contact.

Only foods dissolved in water can gain entry.

4 distinct tastes1.sweet 2.bitter3. salt 4.sour

Sweet and bitter

Pass over taste buds Chemical reaction occurs Receptor cells send message to the brain

Salty and sour

Tastant molecules pass over taste buds Receptor cells do not perceive them An electrical charge occurs Signals the brain

Taste

Tasters 50% Non tasters 25% Super tasters 25% [ potassium chloride, salt

substitute tastes bitter to a super taster] PTC and Sodium benzoate are chemicals

that some people taste and some don not depending on their genetic make up.

INVESTIGATION

Q: Is taste affected by the other senses?Appearance?Smell?Sound?Texture?

Q: How well can you predict the taste identity of a food if one of the other sensory qualities is removed or compromised?

Sensory Evaluation Investigation1. Predict how well you will be able to identify

foods with and without the sense of smell. Ex: 50% without smell, 95% with smell

2. Using a blindfold to remove the sense of sight, you will taste a variety of foods to try to identify them. Each food sample will be tasted with the nose pinched closed and then tasted again with the sense of smell intact.

2. Record your results in a table like this:

Data Table : Individual ResultsFood

ItemWithout

Smell

Correct Incorrect

With

SmellCorrect Incorrect

A

B

C

D

E

F

G

DATA TABLE: Class Results

Group Without

Smell

Correct Incorrect

With

SmellCorrect Incorrect

1

2

3

4

5

6

6

Analysis

1. Calculate the % correct for your group and for the class. How do they compare? Was your hypothesis correct?

2. Why is it easier to identify flavor with smell? 3. Give explanations for the individual differences

among the taste testers. 4. List 3 things that are important about this

experiment 5. List ways to improve this experiment.

Odor Works with flavor No smell- no taste Olfactory- organs

related to sense of smell

Temperature changes odor

Olfactory nerve: a single nerve that ends in sensory cells in the nasal cavityRuns straight to the brainRespond to odors in the form of a gasCilia (nose hairs) have oily mucus that helps dissolve the odor-carrying gas so they can activate the sensitive nerve cells

Olfactory receptor sends its electrical impulse to a particular microregion of the olfactory bulb. The microregion, then passes it on to other parts of the brain. The brain interprets the "odorant patterns" produced by activity as smell. There are 2,000 microregions in the olfactory bulb -- twice as many microregions as receptor cells -- allowing us to perceive a multitude of smells.