Taste, Smell and the Other Senses
Sheryl Hoffmann
Concordia College
shoffmann@concordia.sa.edu.au
Summary of the Workshop
• Goodie bag & Scorecards
• Theory on Senses
• Theory on Taste
• Activities
• Theory on Smell
• Wine Odour Quiz & Tabulation of Results
• Results & Australian Curriculum
5 Traditional Senses
• Taste
• Smell
• Touch
• Sight
• Hearing
ESP the 6th Sense
Extrasensory perception involves reception of
information not gained through the
recognized physical senses but sensed with
the mind.
Other Human Senses
• Temperature
• Pain
• Balance
• Acceleration
Other Human Senses
Various internal stimuli e.g.
• Chemoreceptors for detecting carbon dioxide
concentrations in the blood
• Sensory receptors that sense fullness in the bladder
• Kinesthetic sense – relative position of the parts of the
body
Animals Have Other Senses
• Gravity eg plants
• Electroreceprtion – detect electric fields eg
sharks, platypus
• Magnetoception – detect earth’s magnetic field
eg birds
Taste
The sensation of taste can be categorized into four / five
basic tastes:
• Sweet
• Sour
• Salty
• Bitter
• (Umami)
A Myth
Taste
Taste receptor cells are found in the taste
buds, palate and early parts of the
digestive system like the larynx and
upper esophagus.
Taste bud
https://commons.wikimedia.org/wiki/File:Taste_bud.svg
Sweet
Lots of chemical compounds are sweet:
• All of the simple carbohydrates
• Some aldehydes and ketones
• Some of the amino acids are mildly sweet.
• A number of plant species
• Even some inorganic compounds are sweet, including
Beryllium Chloride and Lead(II) Acetate
Sweet
Hundreds of synthetic organic compounds are sweet but also toxic:
• Chloroform
• Nitrobenzene
• Ethylene glycol
Various artificial sweeteners including:
• Saccharin
• Cyclamate
• Aspartame
A Sense of Sweetness
 Radio National
 5.50pm Monday 13th May 2013
Dr Norman Swan
Sour
Sourness is the taste that detects acidity.
Common sour foods
• Lemon, lime & grapefruit
• Tamarind
• Vinegar
• Pickles
• Sour lollies
Salty
Saltiness is a taste produced
primarily by the presence of
sodium ions, but other ions of
the alkali metals group also
taste salty.
Hallstatt Salt Mine - Near Salzburg
Iodised Salt
• Table salt mixed with a minute amount of various salts of the
element iodine
• Prevents iodine deficiency
• Iodine is a micronutrient
• Naturally present in the food supply in some regions, especially
near sea coasts, but is generally quite rare in the Earth's crust
Bitter
Common bitter foods include
• Coffee
• Unsweetened cocoa
• Marmalade
• Beer (due to hops)
• Many plants in the Brassicaceae family
• Quinine (found in tonic water)
PTC
PTC - phenylthiocarbamide also known as phenylthiourea
Some people taste nothing. Some find it intensely bitter,
and still others taste is as only slightly bitter.
On average, 75% of people can taste PTC, while 25%
cannot.
Umami
Japanese word meaning good flavor" or
"good taste
• A pleasant savoury or meaty taste
• Subtle and blends well with other tastes
to expand and round out flavors
•
Umami
http://www.umami.org.au/
MSG
•
•
•
•
•
•
Mono-Sodium Glutimate
A non-essential amino acid
Taste enhancer
E621
LD50 15-18g / Kg
No scientific evidence for “Chinese Food
Syndrome”
Taste Threshold
Your taste threshold is the lowest
concentration of a solution that a you can
still taste.
Activities
A. Dry tongue, no taste
B. No smell, little taste
C. Number of taste buds
D. Taste threshold of Sweet
E. Taste threshold of Sour
Taste threshold of Salty
G. Taste threshold of Bitter
H. Toothpaste & OJ
F.
Flavour = Taste + Smell
flavour is the sensory impression of a food
or other substance, and is determined mainly
by the chemical senses of taste and smell
How Humans Experience Their Food
primary taste: umami.
How Humans Experience Their Food
▲Back to What is Umami?
http://www.umamiinfo.com/2011/02/What-exactly-is-umami.php
Smell
Olfaction or olfactory perception is the sense of
smell.
The sense of smell is considered to be one of the
least developed senses humans possess.
http://www.exploratorium.edu/cooking/seasoning/taste/smell.html
Odour Thresholds
Detection
The lowest concentration of an odour that is perceivable by the
human sense of smell.
Recognition
The concentration at which you can identify an odor.
Odour Thresholds & MSDS/SDS
Formaldehyde - ES 1 ppm ( 1.2 mg/m3)
Toxic, causes burns, may cause cancer, sensitiser
0.8 ppm typical threshold of perception
0.98ppm typical threshold of recognition
1-2 ppm typical threshold of irritation
At 0.3ppm up to 20% of people will not be protected
ChemWatch Blue
Odour Fatigue
Is the temporary, normal inability to
distinguish a particular odor after a prolonged
exposure to that airborne compound.
Activities
Wine Odour Quiz
Tabulation of Results
Australian Curriculum - Senses
Foundation Year - Science as a Human Endeavour
Nature and development of science
Science involves exploring and observing the world using the senses (ACSHE013)
Foundation Year - Science Inquiry Skills
Questioning and predicting
Respond to questions about familiar objects and events (ACSIS014)
Planning and conducting
Explore and make observations by using the senses (ACSIS011)
Australian Curriculum
Year 9 - Science Understanding
Biological sciences
Multi-cellular organisms rely on coordinated and interdependent
internal systems to respond to changes to their environment
(ACSSU175)
Year 9 - Science Inquiry Skills
Science Inquiry Skills
Taste & smell experiments are simple cheap
and interesting enough to explore and for
students to design their own experiments.
Results
A. Dry tongue, no taste
B. No smell, little taste
C. Number of taste buds
D. Taste threshold of Sweet
E. Taste threshold of Sour
F. Taste threshold of Salty
G. Taste threshold of Bitter
Toothpaste & OJ
Sodium Lauryl Sulfate
• lowers the surface tension of the saliva in your mouth
• suppresses your sweet receptors
• destroys phospholipids thus removing an inhibitors on your
bitter receptors
SLS dulls the sweetness and promotes the bitter taste in orange
juice.
Answer to Wine Quiz
White Wine
1. Mint
2. Lime
3. Honey
4. Vanilla
5. Lemon
Red Wine
6. Blackcurrant
7. Tobacco
8. Pepper
9. Chocolate
10. Raspberry
Referenece
The majority of information came from Wikipedia.
Other references are indicated on individual slides or curated at:
http://www.scoop.it/t/taste-and-smell
Plus:
Page 18 - Dehlia Smith, How to Cook, Book 2, 1999, BBC
Worldwide Ltd London. - TV Series & book
Weebly
Copy of powerpoint & handout:
http://sherylhoffmann.weebly.com/