This document discusses the perception of flavor from a neurological perspective. It defines taste as sensations detected by the tongue alone, while flavor is a multisensory perception incorporating taste, smell, sight, sound, temperature, and even pain. Smell is particularly important for flavor, with retronasal smell crucial for complex flavors. Enzymes play a key role in breaking down foods and releasing volatile molecules that stimulate our flavor receptors. The Maillard reaction is highlighted for its role in producing the attractive smells of cooked meat. Everything from texture to temperature to the sizzle of food contributes to the full flavor experience in the brain.

1. Dr. Russ L’HommeDieu
Dr. Russ L’HommeDDiPeTu
DPT

2. Dr. Russ L’HommeDieu
Dr. Russ L’HommeDDiPeTu
DPT

3. Dr. Russ L’HommeDieu
DPT

4. Dr. Russ L’HommeDieu
DPT

5. Dr. Russ L’HommeDieu
DPT
Disclosures
• http://sccbookrecs.askdocruss.com

6. Dr. Russ L’HommeDieu
DPT

7. Dr. Russ L’HommeDieu
DPT
Disclosures
• http://sccbookrecs.askdocruss.com
• www.loseweightforgood.org

8. Dr. Russ L’HommeDieu
DPT

9. Dr. Russ L’HommeDieu
DPT
Disclosures
• http://sccbookrecs.askdocruss.com
• www.loseweightforgood.org
• www.iloveyoutohealth.com
• Business coaching / consulting
• www.askdocruss.com

10. Always Know the Question
Why are you here?

11. The Obesity Epidemic
The food industry has gotten a bad rap for
their role in the obesity crisis.

12. The Obesity Epidemic
The food industry has gotten a bad rap for
their role in the obesity crisis.
Do they deserve it?

13. The Obesity Epidemic
Good Chefs can no longer get by on loading
food up with fat, sugar and salt and
Great chefs NEVER have.
~Dr. Russ L’HommeDieu

14. Always Know the Question
How does “Flavor”
Differ from
“Taste”?

15. “Taste”
Molecules sensed by receptors on the
tongue.
The neurons of the different tastes go
right to the brainstem and are
hardwired to emotions.
a. Saltiness is essential for maintaining
salty body fluids..
b. Sweetness is innate in all mammals,
because of sugar’s high energy.
c. Sourness warns of food that may
have gone bad.
d. Bitterness warns of toxic substances
that should be rejected.
e. Umami or Savoriness is a meaty
quality, signaling a high-energy food.
The problem is that “taste” does not
account for all the flavor that we can
experience.
Outdated

16. 126 Combinations?

17. With only 126 “tastes”, how do you
explain . . .
Wine Flavor Coffee Flavor

18. “Flavor”
Taste impulses proceed
further to their cortical
areas, where they interact
with all the other sensory
representations at the core
of flavor.
(Adapted from G. M. Shepherd, Smell images and the flavour system in the human brain, Nature 444 [2006]: 316–321)

19. While taste is a sensation of the
tongue, flavor is a
multisensory perception
which includes
taste, touch, smell, vision,
emotion, hearing and even PAIN.

20. Taste is a
Sensation

21. Flavor is
Mulitsensory

22. Flavor is a
Perception

23. While foods do contain molecules that provide
us with flavor, the flavor is not in the food, it’s a
perception that originates in our brain.

24. Why Does
FLAVOR
Matter?

25. Flavor Matters Because
It drives
human
behavior

26. Why Does FLAVOR Matter?
“The human craving for flavor has been a largely
unacknowledged and unexamined force in
history. Royal empires have been built,
unexplored lands have been traversed. . .”
Eric Schlosser, in Fast Food Nation: The Dark Side of the All-American Meal

27. Why Does FLAVOR Matter?
“. . . great religions and philosophies have been
forever changed by the spice trade. In 1492
Columbus set sail to find seasoning.”
Eric Schlosser, in Fast Food Nation: The Dark Side of the All-American Meal

28. Why Does FLAVOR Matter?
“Today the influence of flavor in the world
market-place is no less decisive. The rise and fall
of corporate empires—of soft drink companies,
snack food companies, and fast food chains—is
frequently determined by how their products
taste.”
Eric Schlosser, in Fast Food Nation: The Dark Side of the All-American Meal

29. The Perception of Flavor
Taste
Smell
Temperature
Sight
Sound
Pain

30. The Perception of Flavor: Smell
Two Types of Smell
Orthonasal & Retronasal

31. The Perception of Flavor
Deconstructed: Smell
• Orthonasal
From Monell Chemical Senses Center

32. The Perception of Flavor
Deconstructed: Smell
• Orthonasal
From Monell Chemical Senses Center

33. The Perception of Flavor: Smell
• For flavor to be perceived, molecules need to
reach the olfactory epithelium, located in the
nasal cavity. This can be achieved through
orthonasal (sniff) or retronasal (mouth) airways.
• The intensity perceived will depend on the
number of molecules that reach the receptor
cells.
• Which type of “smell” do you think is most
important to flavor?

34. The Perception of Flavor: Smell
• Whereas taste is analytic,
smell is synthetic.
• What do you suppose this means?

35. The Perception of Flavor: Smell
• It means that smells combine and a
mixture of several smells makes a
new unified smell.
• Knowing what you now know about smell and flavor, how
might this relate to the complexity of human flavor
perception?

36. Smell: Intramodal Enhancement
• When two weak flavor molecules which cannot
be sensed by themselves (sub-threshold), but
together they can be perceived.
• This works for taste and smell together. A weak
smell and weak taste can be subthreshold by
themselves, but together they can be sensed.
• This usually only works if they complement each
other.
• This congruency may be innate, or it may be
learned.

37. Smell: The Molecules of Flavor
• We humans actually have a sense of smell that
is better than the most powerful molecule-detecting
devices available.
• We know this because we can perceive odors
in a food that come from molecules in such
trace amounts that they are undetectable by a
gas chromatograph/mass spectrometer.

38. The Perception of Flavor:
Plant Odors
• Fruit.
Ethylene (ethene) (C2H4) is a volatile molecule
that plays a central role in the ripening of fruit.
When we smell C2H4, we know the peak of
ripening is occurring.

39. The Perception of Flavor:
Plant Odors
• Terpene.
These are five-carbon molecules that can take
many forms. They are common constituents of
plants as well as of fruits, herbs, and spices. The
distinctive smell of pine trees in the forest is due
to terpenes in the tree resins. They are highly
volatile and therefore act quickly when raw
vegetables are cut or chewed, and they are
quickly lost in cooking. They are also highly
reactive with each other and with other
molecules.
Adapted from: On Food and Cooking: The Science and Lore of the Kitchen by Harold McGee

40. The Perception of Flavor:
Plant Odors
• Sulfur.
Sulfur-containing molecules often are produced
by a plant for defensive purposes. They have an
aroma with an “edge” that gives a “pungent”
quality to the smell.
Adapted from: On Food and Cooking: The Science and Lore of the Kitchen by Harold McGee

41. The Perception of Flavor:
Plant Odors
• Phenols.
These are six-member carbon-ring molecules with
a variety of side groups hanging off them.
Different phenolic compounds are responsible for
the main “notes” of different herbs and spices
.
Adapted from: On Food and Cooking: The Science and Lore of the Kitchen by Harold McGee

42. The Perception of Flavor:
Plant Odors
• Green.
This aroma is faint until the plant tissue is torn
apart, or cut, as by a knife, or chewed. These
actions damage the cell membranes, causing an
oxidizing enzyme called lipoxygenase (lipid = fat,
oxygenase = to break down by combining with oxygen) to
act on the fatty molecules that make up the cell
membrane to break them down into small,
volatile fatty acids, which are further dismantled
by other enzymes in the cell contents.
Adapted from: On Food and Cooking: The Science and Lore of the Kitchen by Harold McGee

43. ENZYMES
So, what is the role of enzymes in producing
flavor?

44. ENZYMES
• Enzymes are super important for both flavor and
digestion.
• In fact, the process of digestion begins in the
mouth with an enzyme in the saliva called
amylase.
• The enzyme amylase works to break down starch
into simple sugars such as maltose and dextrin
that can be further broken down in the small
intestine.
• Did you know that about 30% of starch digestion
takes place in the mouth cavity.

45. ENZYMES
So, what is the role of enzymes in producing
flavor?
The role of enzymes in the perception of flavor is
to break down large molecules in food into
smaller molecules which alters their perception
by the flavor system.

46. Meat
• According to Richard Wrangham in his book Catching
Fire: How Cooking Made Us Human, the great leap
forward in the development not only human cuisines,
but also the associated emergence of human culture
and language, was the discovery of the use of
controlled fire to cook foods.
• The greatest effect was achieved by cooking meat. Our
attraction to meat comes mostly from the smell, both
orthonasal and retronasal, smell from ingested food in
the mouth associated with flavor.
• The most attractive volatile molecules from cooked
meat are produced by the “Maillard reaction.”

47. Meat
• The Maillard reaction is a chemical reaction between
an amino acid and a reducing sugar, usually requiring
the addition of heat above 285°F (140°C).
• This is a form of non-enzymatic browning where the
sugar interacts with the amino acids in the meat.
• This process accelerates in an alkaline environment.
• This reaction is the basis of the flavoring industry,
since the type of amino acid determines the resulting
flavor.

48. The Perception of Flavor:
Sight
The sight of our food and drink before we
consume it has a highly significant influence on
how we judge its flavor.

49. The Perception of Flavor:
Sound
The sound of our food as we eat it is an integral
part of the flavor experience. Sizzle? Crunch?

50. The Perception of Flavor:
Feel
Does food texture contribute to the flavor of
food?
The different types of touch that food and liquid
produce in the mouth go to the brain to the
cortex.
The touch receptors in the mouth and tongue
have an enormous representation in the cortex,
which explains why the way our food feels in our
mouth contributes so heavily to taste.

51. The Perception of Flavor:
Pain
Pain commonly signals something to be avoided. Fish
bones, for instance.
While you would think that most people reject food
that causes pain in the mouth, many people learn to
LOVE the pain wrought by the capsaicin (N-Vanillyl-8-
methyl-6-(E)-noneamide ) molecules.
Where are they found? In chili peppers. This is an
example of how the hardwired aversive behavioral
responses at birth can be overcome by learning.

52. The Perception of Flavor:
Temperature
The temperature of food has and effect on all the
somato-sensory pathways for flavor.

53. What is the most important thing
for you to know?
When it comes to flavor, EVERYTHING counts. If
you want happy customers, maximize the flavor
(and thus the emotion) of their experience.
Don’t cop out with French fries (High Fat, High
Sugar, High Salt)
Be creative, be smart and be professional!

54. Dr. Russ L’HommeDieu
Dr. Russ L’HommeDDiPeTu
DPT