Transcript Herbs and Spices

Herbs and Spices
Herbs and spices are what make our food enjoyable. They are
essentially all plant products, and mostly all get their flavor
from plant secondary chemicals. Spices come mostly from
tropical regions, herbs are more from temperate areas. The
herbs’ flavor generally comes from aromatic leaves. The
aroma comes from volatile oils.
Further, many are essential oils built from a basic unit that is a
terpene:
A diterpene phosphate, the carbon backbone is C10H16
The basic unit for these terpenes is C5H8 , but multiples of this
unit are what we find as the essential oils.
Wikipedia lists more than 30 herbs used in cooking of various
international cuisines. We can’t begin to consider all of them.
Among the more important ones are:
From the mint family (Lamiaceae): peppermint, spearmint,
marjoram, oregano, rosemary, thyme, sage, savory and basil
peppermint
oregano
sweet basil
From the parsley family (Apiaceae): parsley, dill, caraway
parsley
caraway
From the mustard family (Brassicaceae): mustard, horseradish
(in the mustards the flavour is released by a reaction between
an enzyme, myrosin, and sinigrin (in stronger black mustards)
or sinalbin (in milder white mustards).
The reaction releases volatile essential oils. Preparation with
acid (vinegar) causes the reaction (and the flavour) to last
much longer.
wasabi
mustard
horseradish
From the lily family (Liliaceae): onion, garlic, leek, shallot,
and chives (all contain closely related sulphurous
compounds; the one in garlic is called allicin since onions,
garlic, etc. are all in the genus Allium. All these species seem
to originate in central Asia. The individual species are:
Onions – Allium cepa
Garlic – A. sativum
Leeks – A. porrum
Shallots – A. ascalonicum
Chives – A. schoenoprasum
garlic in flower
If you need an excuse to eat onions and garlic, here’s what
allicin is believed to do:
1. inhibits pathogenic bacteria by blocking enzymes
they use to penetrate healthy cells
2. inhibits the formation of blood clots (that should
lower the probability of heart attacks and strokes)
3. inhibits cholesterol synthesis (lowering LDL and
probably triglycerides in circulation)
The only problem with consumption of onions, garlic, etc. is
that the sulfurous compounds directly consumed and modified
into others enzymatically enter the circulation from the
digestive tract, are circulated to the lungs, and diffuse into the
gases of the lungs. When you exhale, you smell of the sulfur
compounds.
Many herbs were used for centuries as natural dyes. Some are
also used as spices (note the sneaky transition). Among them:
Tumeric (or turmeric; Curcuma longa, in the same family as
ginger) – a bright yellow rhizome. The active ingredient as a
spice is curcumin. It is actually not a very good dye for cloth,
because it fades readily in light.
However, it is a widely used food dye. It is the reason mustard
and Indian curry powder are yellow.
It also has uses in medicine: It inhibits the plaques that
characterize Alzheimer’s, it helps with STDs chlamydia and
gonorrhea, and has been suggested as an anti-cancer drug.
Indigo was an herbal dye obtained from Indigofera tinctoria.
Aztecs used indigo to dye cloth, and its use continued into the
20th century before replacement by a synthetic dye.
It’s indigo dye that colours our bluejeans. The Celts went into
battle having stained their faces and bodies using a temperate
plant (Isatis tinctoria) that has the same chemical (indigotin)
in the leaves. Think of Mel Gibson playing William Wallace
in Braveheart.
There are closely related species, with flowers that are
‘electric’ blue in midwestern prairies.
Herbal blue dyes were rare; so were herbal red dyes. The one
that was used for centuries was the madder plant (Rubia
tinctorum – rubia indicates red). This is the plant the British
army used to dye the red coats they were famous for at the
time of the American Revolution. The plant is in the same
family as coffee (remember those red fruits?)
Another red dye plant, of great importance in science, was a
bean known to the Aztecs for its dye quality, and later used as
a stain in cellular microscopy, Haematoxylium spp. The dye
used as a cellular stain is hematoxylin.
The dye system used in microscopy combined hematoxylin
(red) with eosin (blue) that stained different parts of tissues
and cells. Hematoxylin has not been replaced with a synthetic
dye.
This is a picture of lung tissue from someone with emphysema
Table 17B in the text lists a number of other plants used as
dyes and the colours they produce. Among the more common:
Black walnut (Juglans nigra) – the pulp surrounding the
walnut is used as a dark brown dye.
Various Coreopsis species’ flower heads (basically petals) are
used to produce an orange dye.
The outer, dry layers of yellow onion (Allium cepa) were used
to make a dye to colour cloth burnt orange.
Lastly, what seems like an unlikely colour from the colour of
the plant tissue extracted: a blue or lavender dye extracted
from the outer leaves of red cabbage (Brassica oleracea).
Spices
Definition (Oxford English Dictionary)
One or other of various strongly flavored or aromatic
substances of vegetable origin, obtained from tropical plants,
commonly used as condiments.
Spices are typically of tropical origin. They are aromatic
plants parts – leaves, twigs, bark, flowers or other plant parts.
The search for spices was one of the driving forces in world
exploration. Going back to the heyday of the Egyptian
pharaohs, herbs and spices were in common use. There was,
even then, an established spice trade between the Mid-East
and Southeast Asia and China.
Arab traders were the agents by the time of the Golden Age of
Greece. Alexander the Great built Alexandria as the key trade
center between Asia and Europe, and the key product in this
trade was spices.
Marco Polo traveled throughout much of China, but also
visited (and later wrote about) Java and India. The spices he
described included pepper, cinnamon and ginger.
Overland trade was slow, inefficient, and subject to seizure
along the route. The exploration of navigators like Vasco de
Gama, Christopher Columbus and others was a search for a
sea route from Europe to Southeast Asia, China and India.
It was Ferdinand Magellan who discovered a route to the
Spice Islands, where cloves, nutmeg and mace were native, in
the course of his round-the-world voyage.
Much more recently, a voyage by Alfred Russell Wallace was
duplicated to show English schoolchildren the Spice Islands.
Apparently it is a tricky and dangerous sailing trip, and
Wallace’s accounts tell much about his travails.
Originally, most spices came from the Old World. More
recently a number of New World spices have been added to
our gustatory spectrum.
Old World spices:
Cinnamon – there are two plant sources, one more properly
called cassia (Cinnamomum cassia) from southeast Asia, and
the other the higher quality cinnamon (Cinnamomum
zeylandicum or aromatica) native to India and Sri Lanka.
The spice we use is the inner bark of the tree for cinnamon or
the whole bark for cassia. That inner bark curls as it dries and
forms what we call cinnamon sticks. Broken pieces are
ground into cinnamon powder.
Pepper – here we need to be careful, there are two very
different kinds of plants described as peppers. The black and
white pepper you grind comes from Piper nigrum, and are the
dried berries of a climbing vine native to India and the East
Indies.
Black pepper comes from picking
these green berries and allowing them
to dry, blacken and shrivel.
White pepper comes from allowing the
berries to ripen on the vine, then
removing the hull, leaving the whitish
seed kernel within.
New World peppers are completely separate. They are in the
genus Capsicum, of which there are 5 major species, but
probably thousands of varieties. All are in the same family
(Solanaceae) as tomatoes, eggplants, and tobacco. To separate
them, sometimes New World peppers are called chili peppers.
They have been in cultivation in the Americas for at least
9,000 years.
“Heat” among these peppers is measured on a scale called
Scoville units. It comes from alkaloids primarily in the ribs
that seeds are attached to within the pepper and the seeds
themselves. The most important is capsaicin. Capsaicin is the
active ingredient in pepper spray. Heat is not necessarily
evident from what species a capsicum pepper is in. For
example, both ordinary bell peppers and cayenne peppers are
varieties of Capsicum annuum (Scoville units <1 to ~40,000).
The hottest peppers are the habanero or Scotch bonnet
peppers (Capsicum baccatum) with a Scoville rating of
100,000 – 300,000. All these peppers originate in southern
Mexico and Central America.
Scoville units: 100,000
– 350,000
Thai peppers: 50,000 – 100,000
Jalapenos: 2,500 - 8000
Green pepper: 0
As a comparison, police pepper spray has a Scoville rating of
500,000 – 5,300,000.
Other old world spices:
Cloves – the dried, unopened flower buds of Eugenia
aromaticum
Nutmeg and Mace - from Myristica fragrans native to the
Spice Islands. The species is dioecious (separate male and
female plants). Mace comes from
a netlike aril within the fruit. The
dried seed within is nutmeg.
Saffron – comes from the stigmas of the flowers of the
autumn crocus, Crocus sativus. It is native to the eastern
Mediterranean and southwest Asia (sometimes called Asia
Minor). You can grow it locally! However, it takes 800,000
stigmas to make up one kilogram, and there are only 3 per
flower. It was used as a yellow dye, and is still used in
cooking both for flavor and to give a yellow colour, for
example in the rice of Spanish paella.
Lastly, vanilla. It comes from the ‘fruit’ pods of the vanilla
orchid, Vanilla planifolia. This is a tropical, perennial vining
orchid originally from southern Mexico and Central America.
Today, the largest producer is Madagascar.
vanillin
To maximize fruit production, flowers are hand-pollinated.
The pods are picked green and allowed to ferment for weeks
to several months, alternately heating and cooling them.
During this process they blacken. During the curing there is a
chemical change, and the pods produce vanilla as crystals on
the pods. The extraction process percolates 35% alcohol over
the cured pods, which extracts both the vanillin and other
chemicals that contribute to the flavor.
Imitation vanilla is now produced (synthesized) from clove
oil, lignin, or coal tar. Now you know why the real stuff tastes
better.