No Slide Title · 2012-08-10 · •Molecular Gastronomy has its origins in a series of workshops...
Transcript of No Slide Title · 2012-08-10 · •Molecular Gastronomy has its origins in a series of workshops...
AIChE Webinar 26 October 2011 Peter Barham - Department of Physics, University of Bristol, UK
- Department of Food Science, University of Copenhagen, DK - Animal Demography Unit, University of Cape Town, RSA
Molecular Gastronomy The Science of Taste and Flavour
2
Where did it all start
• Molecular Gastronomy has its origins in a series
of workshops for chefs and scientists held in Erice
in Sicily initially suggested by Elizabeth Thomas
and organised by Nicholas Kurti.
• The meetings were called “International
Workshops on Physical and Molecular Aspects of
Gastronomy”. Later abbreviated to Molecular
Gastronomy.
4 What is Molecular Gastronomy?
Today, we want to understand what it is that
makes one dish delicious and another not;
whether it be the choice of ingredients and
how they were grown; the manner in which
the food was cooked and presented; or the
environment in which it was served.
5
Example: Salt – why use it?
Most people, when they cook, add salt to nearly
everything.
Almost all recipes call for a “pinch of salt”.
But is it really necessary?
6
Salt and green vegetables • Reasons given to add salt
• It raises the boiling point
• It decreases the boiling point
• It makes water boil more vigorously
• It „fixes‟ the color
• It adds seasoning
• What it actually does today • It raises the boiling point (by a fraction of a degree)
• It encourages nucleation and so gives the appearance of vigorous boiling
• What it may have done in the past • Divalent ions can replace any missing Mg in the chlorophyll – this
can lead to a color change from brown to green
7
Taste sensations
•Salt
•Sweet
•Bitter
•Sour
•Umami
We each have five different types of taste buds distributed around the
tongue and the sides of the mouth.
•Salt an essential nutrient we would not get in a „natural‟ diet
•Sweet the taste of sugars needed to provide bursts of energy
•Bitter the taste of alkaloids – potentially toxic substances
•Sour the taste of acids – possibly dangerous
•Umami the taste of an essential nutrient – amino acids
Particularly the taste of the sodium salt of glutamic
acid
Also known as mono (sodium glutamate)
Or MSG
8
Perception of Flavour
Flavour is the combination of taste in the mouth (from the
taste buds) and aroma in the nose.
Our noses are very much more sensitive than our tongues
– we have around 400 different types of aroma sensor
compared to just 5 types of taste sensors.
9 Perception of Flavour
An easy way to demonstrate the importance of aroma is
to try to identify the flavor of a food while holding your
nose – without the information about aroma you cannot
tell what you are eating.
This is why food tends to lose its flavor when you have a
cold and your nose is blocked.
Interestingly we detect different aromas depending on
whether we are breathing in (ortho-nasal) or out (retro-
nasal.
This explains why some really smelly foods taste so good.
– the best example is Durian fruit, but really ripe soft
cheeses also have the same effect.
10
Adaptation
Our sense of smell evolved to help us
know what is in our environment.
We thus are more sensitive to changes in
the aromas around us.
This means that we quickly ”adapt” to
aromas – ignoring constant smells.
In food, constant flavours become “boring”
and are ignored.
Perception of Flavour
11 Perception of Flavour
In practice flavour is constructed in our minds.
We use all our senses to determine flavour.
What we see tells us what to expect.
A white wine coloured red will evoke red
wine memories and descriptions.
The colour of the plates on which we
serve food affects expectations and thus
appreciation. Food served on patterned
or blue plates often has a poorer rating
than food served from plain white plates.
12 Perception of Flavour
What we hear affects how we eat.
Try recording yourself eating a crunchy
food and then play the sound back while
trying to eat something soft.
Or take some chips and simply crush
them in your hands near the ears of a
„friend‟ who is trying to eat!
If you listen to music when eating, you
are liable to start to chew in time to the
beat.
13 Perception of Flavour
What we feel affects how we perceive
texture.
Try eating a creamy food (maybe a
yogurt) – note how creamy you think it
is.
Take a second spoonful while stroking
a smooth silky surface – it will
probably seem creamier.
Take a third spoonful while rubbing
your hand with sandpaper – the food
will probably seem a little gritty.
14
Molecular Gastronomy: A New Emerging
Scientific Discipline
Peter Barham, Leif H. Skibsted, Wender L. P.
Bredie, Michael Bom Frøst, Per Møller, Jens
Risbo,Pia Snitkjær and Louise Mørch Mortensen
http://pubs.acs.org/doi/abs/10.1021/cr900105w