Taste & Smell: Chemical senses

• McDonald’s Fries– Win best taste competitions– Not the method, potatoes, or machinery– Taste of fried foods determined by

cooking oil– McD’s uses 7% cottonseed oil, 93%

beef tallow: a fry has more beef fat/ oz than a burger

– McD’s worldlocations

Obviously there was criticism

• McD’s changed to pure veg. oil 1990

• Problem: how to make them taste like beef without using beef?

• “natural flavor”– Explains why most of our food taste the way it

does.

Natural Flavor vs. Artificial Flavor

• Both are man made• 90% of our food $ is for processed food• Canning, freezing, & dehydrating destroy flavor• Big money in making flavor• Name food brands• Name the companies that makes flavor

International Flavors & Fragrances (IFF)

• World’s largest flavor company– Also makes smell of best selling perfume’s,

deodorant, and soaps– 2005: 1.9 Bil.

• Givaudan: 2nd

• Haarman & Reimer: Largest German

• Takasago: Largest Japanese

Smell owns taste

• Aroma can be 90% of a food’s flavor

• What evolutionary benefit would organisms with a better sense of smell have?– Find food– Distinguish good food

from bad

Evolution puts pressure on us.

Flavors vs. smells

• Taste buds can detect ~ 5 basic flavors– Sweet, sour, bitter,

salty, astringent, umami

– About 4-10K taste buds on tongue, cheek, pharynx, epiglottis

– Bumps called papillae

• Olfactory system can percieve thousands of different chemicals

Mastication releases gases

• Thin layer of nerve cells called olfactory epithelium receives gases and transduces them into smell signals

• Brain combines smells signals with simple taste signals and decides if its something you want to eat.

Food preferences & personality form early in life

• Babies will adjust to hot & spicy, bland health food, or fast food depending on what the people around them eat.

Baby eating sushi

We don’t know it all yet

• Psychosomatic effects happen

• Color of food can determine perception of its taste

• People can grow accustomed to bad smells. – Come back from a long vacation

and immediately take a good whiff of what your house smells like. Other people smell that whenever they visit you

Aroma & memory• Nerve signals for smell go right past parts

of our brain associated with memory.– Smelling salts (ammonium carbonate can

wake you up by causing an inhalation reflex– Smells can bring back memories– Comfort foods– McD’s makes billions on this (Happy Meals)

Flavor in history

• Empires built, seas crossed, religions and philosophies changed over taste.

• Columbus went looking for flavor

• Salzburg Germany: Founded to protect salt trade

• Saffron is 12$ a gram

• So artificial flavors cropped up from perfume companies after canning started

• German scientist playing with chemicals: suddenly lab smells like grapes methyl anthranilate grape Kool-Aid purplesaurus rex

1.4 Bil a year

• ~10K new food products a year

• ~9/10 fail

Tech

• Spectrometers

• Gas chromatographs

• Vapor detectors

• Can discern chemicals at 1 ppb

• Human nose can tell 0.000000000003 %

• Dogs better still

Complex flavors

• Coffee, roast beast, strawberries; thousands of chemicals at once

• Chemical responsible for flavor of Bell pepper only need 0.02 ppb: a drop could flavor a swimming pool

• And its cheap: flavor in 12oz of Coke = ½ cent

• Often though, 1 chemical provides the over-riding sense of the food.

• Ethyl-2-methyl butyrate = apple

• Methyl-2-peridylketone = popcorn

• Ethyl-3-hydroxybutanoate = marshmallow

• Hexanal = fresh cut grass

• 3-methyl butanoic acid = B.O.

So what?So natural flavor means its made using old technology

• Natural

Getting amyl acetate from distilling bananas with a solvent

• Artificial

Getting amyl acetate from mixing vinegar with amyl alcohol, adding H2SO4 as a catalyst

Both taste exactly the same, both happen in the same factory, but people want to see natural on their label.

Art or Science?

• Mouthfeel: Its not just flavor,

• TA.XT2i Texture analyzer uses 250 probes to create an artificial mouth that senses bounce, creep, crunch, density, chewiness, gumminess, lumpiness, rubberiness, slipperiness, softness, wetness, spread, spring-back, tackiness

• How do you juggle all of this with subtleties of flavor?

Genetics

• Dominant gene • Phenylthiocarbamide,

also known as PTC, or phenylthiourea tastes very bitter or not at all depending on genetics

• Discovered when a guy at duPont accidently spilled a bunch of crystalline PTC, some complained, some did not

• May explain why some people are more offended by cig. smoke

Super Taster

~25% of people of European dissent

• Maybe more fungiform papillae

• Linked to food preference, body type

• Coffee, alcohol, may be too intense

• Olives too salty

Things go horribly awry• Ageusia (pronounced ay-GOO-see-uh)

Loss of sense of taste – From neural damage

• anosmia - a loss of the sense of smell. – Cold– Parkinson’s– Alzheimer's