Caffeine and Plant Beverages: Sources, Effects, and Processing, Slides of Sociology

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Plant Beverages with Caffeine

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.

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

Other sources of caffeine:

• Mate, Ilex paraguariensis
• Guaraná, Paullinia capana
• Kola, Cola nitida

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

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 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.

Milk chocoloate – has milk solids + sugar + unsweetened chocolate

Semisweet and bittersweet – sugar added

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