Thursday Lecture – Plant Beverages
with Caffeine
Reading: Textbook, Chapter 13
Quiz
Quiz
1. The alkaloid from this New World plant passes into the
brain more rapidly than heroine or cocaine and is thus
highly addictive – what is the name of the alkaloid and
what is the name of the plant?
2. The world’s most widely used psychoactive drug is
caffeine, which is produced by a variety of different
plants – name a plant source of caffeine originally
native to the New World and one originally native to the
Old World.
Caffeine and Theobromine –
Mild Stimulants
- alkaloids (note N, ring structure)
caffeine
- “methylated xanthines”=
methylxanthines
theobromine
Caffeine and Theobromine –
Mild Stimulants
- alkaloids (note N, ring structure)
caffeine
- “methylated xanthines”=
methylxanthines
Effects of Caffeine:
- central nervous system stimulant
theobromine
Caffeine and Theobromine –
Mild Stimulants
- alkaloids (note N, ring structure)
caffeine
- “methylated xanthines”=
methylxanthines
Effects of Caffeine:
- central nervous system stimulant
- mild diuretic
theobromine
Caffeine and Theobromine –
Mild Stimulants
- alkaloids (note N, ring structure)
caffeine
- “methylated xanthines”=
methylxanthines
Effects of Caffeine:
- central nervous system stimulant
- mild diuretic (makes you go “pee”)
theobromine
Caffeine and Theobromine –
Mild Stimulants
- alkaloids (note N, ring structure)
caffeine
- “methylated xanthines”=
methylxanthines
theobromine
Effects of Caffeine:
- central nervous system stimulant
- mild diuretic
Mode of action:
- interferes with enzyme, so that adrenaline remains active  alert feeling
Caffeine and Theobromine –
Mild Stimulants
- alkaloids (note N, ring structure)
caffeine
- “methylated xanthines”=
methylxanthines
theobromine
Effects of Caffeine:
- central nervous system stimulant
- mild diuretic
Mode of action:
- interferes with enzyme, so that adrenaline remains active  alert feeling
- blocks adenosine receptors  inhibits sleep signals
Caffeine and Theobromine –
Mild Stimulants
- alkaloids (note N, ring structure)
caffeine
- “methylated xanthines”=
methylxanthines
theobromine
Effects of Caffeine:
- central nervous system stimulant
- mild diuretic
Mode of action:
- interferes with enzyme, so that adrenaline remains active  alert feeling
- blocks adenosine receptors  inhibits sleep signals
Note: latter activity also interacts with dopamine receptors
Health Effects of Caffeine
Most widely used psychoactive drug
- small amounts  no long term effects have been noted
Health Effects of Caffeine
Most widely used psychoactive drug
- small amounts  no long term effects have been noted
- even small amounts taken regularly can produce withdrawal if
stopped (often manifested as headaches)
Health Effects of Caffeine
Most widely used psychoactive drug
- small amounts  no long term effects have been noted
- even small amounts taken regularly can produce withdrawal if
stopped (often manifested as headaches)
- large amounts  adverse symptoms such as anxiety, insomnia
Health Effects of Caffeine
Most widely used psychoactive drug
- small amounts  no long term effects have been noted
- even small amounts taken regularly can produce withdrawal if
stopped (often manifested as headaches)
- large amounts  adverse symptoms such as anxiety, insomnia
- dose-dependent, so that effects on young, unborn
NOTE: current recommendations, pregnant women should reduce
or eliminate caffeine consumption during pregnancy
Health Effects of Caffeine
Most widely used psychoactive drug
- small amounts  no long term effects have been noted
- even small amounts taken regularly can produce withdrawal if
stopped (often manifested as headaches)
- large amounts  adverse symptoms such as anxiety, insomnia
- dose-dependent, so that effects on young, unborn
NOTE: current recommendations, pregnant women should reduce
or eliminate caffeine consumption during pregnancy
- effects on other animals can be different, e.g. dogs, cats, birds
Major Plant Sources of Caffeine
Coffee – Coffea arabica and related species
Chocolate – Theobroma cacao
Tea – Camellia sinensis
Major Plant Sources of Caffeine
Coffee – Coffea arabica and related species
Chocolate – Theobroma cacao
Tea – Camellia sinensis
Other sources of caffeine:
- Mate, Ilex paraguariensis
- Guaraná, Paullinia capana
- Kola, Cola nitida
Tea –Beverage of the World
Camellia sinensis – Theaceae
Shrub, native to China
Tea – In the Field
Tea Shrubs are grown in
large plantations
Picking is done by hand –
only the shoot tips are taken
Tea – Processing
Tea Types
White tea – leaves are dried only; weak
Tea Types
White tea – leaves are dried only; weak
Green tea – leaves are steamed (destroys fermentation enzymes),
dried, and rolled; weak
Tea Types
White tea – leaves are dried only; weak
Green tea – leaves are steamed (destroys fermentation enzymes),
dried, and rolled; weak
Black tea – leaves are withered, rolled, fermented, dried; strong
Tea Types
White tea – leaves are dried only; weak
Green tea – leaves are steamed (destroys fermentation enzymes),
dried, and rolled; weak
Black tea – leaves are withered, rolled, fermented, dried; strong
Oolong tea – intermediate between black and green – short
fermentation
Food of the Gods
Theobroma cacao – Sterculiaceae
Understory tree, native to New
World
Cacao - the Cauliflorous Tree
Main Varieties:
Criollo (“native”) – best
quality, worst yield, worst
disease tolerance
Cacao - the Cauliflorous Tree
Main Varieties:
Criollo (“native”) – best
quality, worst yield, worst
disease tolerance
Forastero (“foreign”) – worst
quality, best yield, best
disease tolerance
Cacao - the Cauliflorous Tree
Main Varieties:
Criollo (“native”) – best
quality, worst yield, worst
disease tolerance
Forastero (“foreign”) – worst
quality, best yield, best
disease tolerance
Trinitario – hybrid of other
two, intermediate in quality,
yield, and disease tolerance
Cacao - the Cauliflorous Tree
Cacao - the Tropical Crop
Chocolate Chemistry
Caffeine – less than coffee (chocolate bar 30 mg; cup coffee, 100 mg)
Theobromine – stimulates heart muscle
Chocolate Chemistry
Caffeine – less than coffee (chocolate bar 30 mg; cup coffee, 100 mg)
Theobromine – stimulates heart muscle
Phenylethylamine – reputed to be “mood elevator”, antidepressant
- found in brain; low levels linked to depression; chocolate contains
low levels of PEA; knowledge of chemistry still incomplete
Chocolate Chemistry
Caffeine – less than coffee (chocolate bar 30 mg; cup coffee, 100 mg)
Theobromine – stimulates heart muscle
Phenylethylamine – reputed to be “mood elevator”, antidepressant
- found in brain; low levels linked to depression; chocolate contains
low levels of PEA; knowledge of chemistry still incomplete
Chocolate Myths:
- chocolate does not cause acne
Chocolate Chemistry
Caffeine – less than coffee (chocolate bar 30 mg; cup coffee, 100 mg)
Theobromine – stimulates heart muscle
Phenylethylamine – reputed to be “mood elevator”, antidepressant
- found in brain; low levels linked to depression; chocolate contains
low levels of PEA; knowledge of chemistry still incomplete
Chocolate Myths:
- chocolate does not cause acne
- chocolate is not a trigger for migraines
Chocolate Chemistry
Caffeine – less than coffee (chocolate bar 30 mg; cup coffee, 100 mg)
Theobromine – stimulates heart muscle
Phenylethylamine – reputed to be “mood elevator”, antidepressant
- found in brain; low levels linked to depression; chocolate contains
low levels of PEA; knowledge of chemistry still incomplete
Chocolate Myths:
- chocolate does not cause acne
- chocolate is not a trigger for migraines
- chocolate is probably not an aphrodisiac
Chocolate Chemistry
Caffeine – less than coffee (chocolate bar 30 mg; cup coffee, 100 mg)
Theobromine – stimulates heart muscle
Phenylethylamine – reputed to be “mood elevator”, antidepressant
- found in brain; low levels linked to depression; chocolate contains
low levels of PEA; knowledge of chemistry still incomplete
Chocolate Myths:
- chocolate does not cause acne
- chocolate is not a trigger for migraines
- chocolate is probably not an aphrodisiac
NOTE: chocolate “craving” is probably real; reasons, mechanism are unclear
Cacao - Processing
1. Seeds are spread out and allowed to ferment
2. Fermented seeds are dried and roasted
3. Seed coats are removed
4. “Nibs” are ground, which produces a thick liquid called
chocolate liquor (non-alcoholic)
5. Chocolate liquor is fed through a high pressure press
which separates the fat (cocoa butter) from the solids
(cocoa powder)
6. The cocoa butter and cocoa powder can be recombined
together with sugar or milk to produce chocolate
Cacao – Processing 2
Notes:
Chocolate liquor is intensely flavored, bitter – diluted with water
and flavored it provides a drink – this is how Montezuma and
other Aztec royalty would have consumed it, flavored with
vanilla and chili pepper
Cacao – Processing 2
Notes:
Chocolate liquor is intensely flavored, bitter – diluted with water
and flavored it provides a drink – this is how Montezuma and
other Aztec royalty would have consumed it, flavored with
vanilla and chili pepper
Cocoa powder contains the chocolate flavor – it can be darkened
and the flavor intensified by treating with alkalinization =
“Dutching”
Cacao – Processing 2
Notes:
Chocolate liquor is intensely flavored, bitter – diluted with water
and flavored it provides a drink – this is how Montezuma and
other Aztec royalty would have consumed it, flavored with
vanilla and chili pepper
Cocoa powder contains the chocolate flavor – it can be darkened
and the flavor intensified by treating with alkalinization =
“Dutching”
Cocoa butter is the fat – it is tasteless but has the distinctive
property of melting at about the human body temperature
Cacao – Processing 3
Further Notes:
Two other processes are critical to the production of chocolate
Conching – the chocolate is placed in a machine and mixed with
steel beads, the heat generated by friction alters the texture of the
cocoa/sugar particles. The highest quality chocolate is conched
for about 72 hrs, low quality chocolates only for about 4-6 hrs
Tempering – chocolate is heated to enhance the development of
crystals of cocoa butter with the proper characteristics: snap
rather than crumble and melt at body temperature
Chocolate – the Products
Unsweetened: Chocolate liquor + cocoa butter,
no sugar
-- mole sauce etc.
Chocolate – the Products
Unsweetened: Chocolate liquor + cocoa butter,
no sugar
-- mole sauce etc.
Semisweet
and
bittersweet –
sugar added
Chocolate – the Products
Unsweetened: Chocolate liquor + cocoa butter,
no sugar
-- mole sauce etc.
Milk chocoloate – has milk solids +
sugar + unsweetened chocolate
Semisweet
and
bittersweet –
sugar added
Coffee – Out of Africa
1. Discovery in Ethiopia (goats, goatherds, goddesses?)
Coffee – Out of Africa
2. 1600s – spread to Europe of coffee drinking
Coffee – Out of Africa
3. 1700s – Dutch plantations in East Indies (“Java”)
Coffee – Out of Africa
4. French take (smuggle?) coffee to West Indies (Martinique)
Coffee – Out of Africa
5. Coffee production starts in Brazil (now #1 producer)
Coffee arabica
Coffea – member of Rubiaceae
- Shrubs
- Fruit = berry
- Pericarp, seed coats removed
 seed used
This Bean is a Berry
The coffee fruit is a berry, sometimes called a “cherry”
The “bean” is the interior of the seed, with the seed wall removed
Hand-picking selects the best quality fruits
Coffee Processing
1. Seeds dried, fermented (chemical fermentation)
2. Seeds roasted (hot air)
3. Seeds ground, brewed
Coffee Issues
1. Pollution
- processing of coffee (in beneficios)  large amount of water
2. Disease
- fungal diseases wiped out coffee production in Sri Lanka (Ceylon)
- fungal diseases still threaten crops in Brazil
3. Shade vs. sun coffee
- traditionally, coffee grown under shade
 coffee plantations preserve biodiversity
4. Decaffeination – solvent vs. water extraction
- solvent extraction  caffeine recovered, sold
Thursday Lecture – Alcoholic
Beverages
Reading: Textbook, Chapter 14