Tas and Sensaon Tas and Sensaon (gustation)
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Taste and SensationTaste and Sensation(gustation)
Anatomy of Taste
papillae are not taste buds
Anatomy of TasteFour primary types of papillae:
• Vallate (or Circumvallate)- large, near back of tongue
• Foliate- on side of tongue
• Fungiform- larger, ‘mushroom’ shaped- “buds”
• Filiform- cover majority of tongue and
does not contain taste buds- used for mechanical grinding
Anatomy of Taste
Anatomy of Taste
taste buds (3)
papillae (plural)papilla (singular)
Fungiform papillae each have ~ 1-5 taste buds eachOthers can contain many more - up to 100 each
Each taste bud consists of 50 - 150 taste receptor cells
Taste buds are located within the papillae
Anatomy of Taste
neurons
Anatomy of Taste
Salt
Sour
Acidity - lactic, acetic and citric acid
Bitter
Probably developed as defense mechanism
and... Umami From the Japanese word ‘umami’ which means delicious
Na+Cl-
Sweet
5 basic qualities of taste (gustatory stimulation)
citric acid
Sweet and Umami
HO
O
NH2
O-Na+
O
monosodium glutamate
O
OOH
HO
HO
HO
HO OH
OOH OH
Sucrose (glucose & fructose)
nutritive sweetener
Saccharin (Sweet-N-Low)(300-500 x)
Sucralose (Splenda)(600 x)
SO2
NH
O
O
OOH
HO
Cl
HO
HO OH
OCl Cl
Aspartame (NutraSweet/Equal)(180-200 x)
Neotame(7000-13000)
NH
O OMeOH2N
HO2C
NH
O OMeOHN
HO2C
non-nutritive sweeteners
Umami:
N+ NH
ODenatonium
needs more work...
Bitter
Sour
citric acid
SaltyNa+ ions
flows into ion channels
causes polarization/depolarization within
cell and…
opens voltage dependent Ca2+
channel
increase in Ca2+ causes generation of
ATP (neurotransmitter)
SourH+ ions
flows into ion channels
H+ blocks a K+ channel
opens voltage dependent Ca2+
channel
H+ flow causes polarization/
depolarization within cell and…
increase in Ca2+ causes generation of
ATP (neurotransmitter)
SweetG-protein coupled
receptors (GPCRs)
cAMP transduction cascade
Blocks K+ channel
causes polarization/depolarization within
cell and…
opens voltage dependent Ca2+
channel
increase in Ca2+ causes generation of
ATP (neurotransmitter)
BitterG-protein coupled
receptors (GPCRs)
cAMP transduction cascade
CAN Block K+ channel
polarization/depolarization within
cell and…
opens voltage dependent Ca2+
channel
increase in Ca2+ causes generation of
ATP (neurotransmitter)
5th Cranial (Trigeminal) Nerve (Somatosensory System)
hot/coldtexture, mouthfeel, astringency
tingle/prickling
7th, 9th and 10th Cranial Nerves(Gustatory System)
5 basic qualities of taste
of the 12 pairs of cranial nerves...
Facial nerveTrigeminal nerve
Vagus nerve
Glossopharyngealnerve
5th Cranial (Trigeminal) Nerve (Somatosensory System)
hot/coldtexture, mouthfeel, astringency
tingle/prickling
7th, 9th and 10th Cranial Nerves(Gustatory System)
5 basic qualities of taste
of the 12 pairs of cranial nerves...
Facial nerveTrigeminal nerve
Vagus nerve
Glossopharyngealnerve
Somesthetic senses - responsible for chemical sensibility of the skin and mucus membranes.
• coolness of menthol• warming of chili peppers• tingle of carbonation
Tingle compounds
NH
O
NH
O
OH
enhances carbonation and alcoholic effect,cooling, warming and sweetness
refreshing or cleansing
Somatosensory system- made up of MANY nerves
hydroxy alpha sanshool
The sanshool chemicals, such as alpha-hydroxy-sanshool from the Japanese Sanchoo pepper and other Asian peppers, are particularly interesting because they not only give a hot sensation in the mouth cavity but also a tingling effect on the tongue
Tingle compounds
hydrophobic tail (lipid solubility)hydrophilic head (binding to receptor/nerve ending)
hydrophilic/hydrophobic balance required for trigeminal stimulation
{ {
NH
O
NH
O
OH
conjugated amide
NH
O
O
ONH
O
Synthetic Compounds
Cooling compounds
Mouthwash, body wash, shampoo, chewing gum, mints
OH
(+) menthol
OH
(-) isopulegol
Synthetic Compounds
O
O
OHO O
OOH
HNO O
NO
• hydrogen-bonding group• compact hydrocarbon skeleton• must have correct hydrophilic/hydrophobic balance
Pungent, Warming and Hot Irritants
pepper, chili pepper, ginger, mustard, horseradish, Wasabeact on thermal receptors
O
HO
NH
O
capsaicin(chili pepper)
N
O
Piperine(black pepper)
O
O
O
HO
O
zingerone(ginger)
O
HO
O
6-gingerone(ginger)
OHN C S
allyl isothiocyanate(mustard/horseradish/Wasabe)
Tannins - polyphenols
Astringency - irritate tactile receptors
Menthol
mintiness - olfactory stimulationirritation, cool/hot - somatosensory stimulationbitterness - gustatory stimulation
OH
All these add up to our perception of FLAVOR
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