SENSORY EVALUATION of FOOD

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SENSORY EVALUATION of FOOD
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Why we eat?

• Hunger
• Fuel our bodies
• Psychological ( emotional eating)
• Boredom

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Nutrient--

• to nourish
• Chemicals the body needs to function, grow,
  repair itself and creates energy.

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Basic Nutrients

• Proteins
• Carbohydrates
• Fats
• Vitamins
• Minerals
• Water

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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

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We taste with all of our senses.

• our flavor perception is actually determined by
  the
• Smell
• Taste
• Appearance
• sound

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• 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).

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'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.

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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

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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.

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• 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).

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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).
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• 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.

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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.

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• 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.

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• 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.

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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.

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• 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.

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• 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.

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

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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.

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• 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.

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• 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.

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• 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.

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SENSES

• Flavor is the distinctive quality that comes
  from foods blend of
• Appearance
• Taste
• Smell, odor
• Feel, texture
• Sound

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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.

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

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Sweet and bitter

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

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Salty and sour

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

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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.

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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?

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Sensory Evaluation Investigation

• 1. 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

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Data Table Individual Results
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DATA TABLE Class Results
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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.

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Odor

• Works with flavor
• No smell- no taste
• Olfactory- organs related to sense of smell
• Temperature changes odor

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• Olfactory nerve a single nerve that ends in
  sensory cells in the nasal cavity
• Runs straight to the brain
• Respond to odors in the form of a gas
• Cilia (nose hairs) have oily mucus that helps
  dissolve the odor-carrying gas so they can
  activate the sensitive nerve cells

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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.
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