Starchy (non-grass) Staples
-mostly root crops
-mostly of tropical origin, though often
temperate & tropical cultivation now
-mostly propogated asexually
-highly productive & often economically
important
-often among first plants used &
domesticated by humans
-often low in protein & oils
Starch: (from- http://www.carbs-information.com/starch.htm)
Starch is a type of carbohydrate. Specifically, starch is a complex
carbohydrate (polysaccharide) made from thousands of glucose units.
Starch is the main compound that plants use to store their food energy.
Starch is One of Three Types of Carbohydrates
There are three basic types of carbs: (1) starchy carbohydrates
(polysaccharides); (2) sugars (monosaccharides or disaccharides) and (3)
dietary fiber (polysaccharides). Carbs are one of three main food nutrients:
the others being protein and fat.
Starch is a Plant Chemical
Chemically speaking, starch is a white, odorless, tasteless, solid
carbohydrate, typically composed of long chains of glucose molecules (1000
or more). The most common forms are amylose and amylopectin. Plants
store the energy produced by photosynthesis in the form of starch.
Starch is a Complex Carbohydrate
Because the molecular structure of complex carbohydrates is more
complicated than more simple carbohydrate sugars, like sucrose and
glucose, the body cannot metabolize complex carbs into energy as quickly
as simple carbs. Result? Complex carbs are not digested and turned into
energy as fast as sugars and therefore keep us full for longer.
Starch (cont.)
Starch is an Intermediate or High Glycemic Index Food
However, the classification of carbs into "simple" or "complex
carbs" has been superceded by the Glycemic Index, which rates
carbs according to their effect on blood-glucose levels. Many
starchy foods (eg. potatoes) are now classified as intermediate or
high-glycemic-index foods and should (for best effects on bloodsugar and insulin sensitivity) be eaten in combination with lower
glycemic index foods.
Starch in Foods
Starch is found in plant-based foods, especially cereals, bread,
potatoes, legumes (beans), pasta and rice, which are all classified
as "starchy carbohydrates." Starch is also found in some fruits,
vegetables, and in the roots and stem pith of plants.
Starch continued
• Starch is made and stored in plastids: e.g.,
chloroplasts in leaves, and amyloplasts in roots.
• Salivary enzymes in humans begins the
breakdown of starch in the mouth, giving a
slightly sweet taste.
• In traditional diets, provides 85% of the total
carbohydrates consumed; sugars only 15%.
• In socioeconomically rich countries, provides
only 62% of the total carbohydrates consumed
and sugars provide 38%.
Starch makes a stand
USA Today.com 25 Feb 2004
• Potatoes, pasta, rice and bread-once the high-carb
heroes of dieters and marathon runners – are being
snubbed by consumers caught up in the lowcarbohydrate craze
• Potato: 100 calories for 1 medium size, 45% RDA
Vitamin C; 21% Calcium
• ‘good’ carbohydrates: nutrient-rich complex ones,
found in plant food such as fruits, vegetables, whole
grains, beans
• ‘bad’ carbohydrates: highly processed & refined foods
• ‘most of the world bases their diets on carbohydrates,
and they don’t have the obesity rates we do because
they eat less & exercise more’
Important starchy foods: (International Starch Institute, Denmark;
http://home3.inet.tele.dk/starch/isi/starch/botany.htm)
Amaranth*
Arrow Root**
Banana*
Barley**
Cassava***
Maize***
Millet**
Oat**
Potato***
Rice**
Rye
Sago**
Sorghum**
Sweet Potato**
Wheat***
Yam*
***
**
*
A major raw material for industrial starch
A raw material for industrial production in confined areas
A crop with potential but limited use as a raw material for starch
Modified stems and roots
• Stems
– Stolons or runners
• horizontal stems, long internodes, found above ground
– Rhizome
• horizontal underground stems
– Bulb
• vertical underground stem; food reserves in leaves
– Corm
• vertical underground stem; store food reserved in stem
• Storage Roots
– Tuber
• enlarged storage tips of rhizome
– Tuberous root
• fleshy fibrous roots, enlarged with food reserves
– Taproot
• biennial plants
“Potatoes”
• White, Sweet, and Yams
• Each a different species in a different
family
– White = Solanum tuberosum; Solonaceae
– Sweet = Ipomoea batatas; Convolvulaceae
– Yam = Dioscorea species; Dioscoreaceae
(White) POTATO
• “ scarcely innocent underground stem of
one of a tribe set aside for evil”
• “ could be used for exciting Venus”
• “could cause leprosy”
• “the English or Irish potato increaseth thy
seed and provoketh lust in both sexes”
“Potatoes are for peasants”
• Nobles/wealthy wanted peasants to eat
potatoes and save wheat for nobility &
export
• Easy to to cultivate
• Matures in 4 months
• High production
• Easy to prepare (just boil)
Solanaceae
(Nightshade or Potato family)
• simple, alternate leaves
• flowers are 5-mers
• sepals and petals fused
into a tube
• fruit a berry or capsule
• 85 genera, ca. 2800
species
• includes tomato,
potato, tobacco,
eggplant, nightshade,
carolina horse nettle,
mandrake, henbane
Market in Peru: farmers in the Andes cultivate up to 3,000 potato varieties.
The white potato
• Tuber crop
• Eye = buds located at the
nodes; each bud can give
rise to a new plant
• Origin = Andean highlands
of S. America
• Ca. 8000 years ago
• Staple of Incas
• Introduced to Europe ca.
1625
• Biggest producers are N.
Europe & China
White potato continued
U.S. crop mostly from Idaho, Washington, & Maine; but planted widely;
50% used for french fries & chips
>6000 cultivars of white potato known (12 make up most of U.S. crop)
Herbaceous annual
Cool-season crop
Only the tuber is non-toxic
GM versions rare
Four common types: round white, russet, round red, long white
High in CHO (ca. 25% FW); low in protein (2.5%), but it’s high quality;
little fat; lots of vitamins & minerals & fiber
The Potato: a cautionary tale
Late blight in potato
•
•
•
•
•
•
•
•
•
•
•
Introduced into Europe (Isle of Wight) in 1625 from Americas
Became most important in Ireland; allowed for population explosion; but
most of Ireland (the poor) relied very heavily on it for food
Major potato pathogen in Ireland is a fungus, Phytophthora infestans
In Ireland, major epidemics in 1845-49: island-wide potato failure
Control measures known at that time: plant only every 6th year, use clean
seed tubers not connected to diseased field; do not feed diseased tubers to
stock w/o boiling
Ireland = agricultural colony of Great Britain
absentee (foreign, English) landlords - Irish serfs
potato = major staple; wheat = export crop to England
no major industries: elimination of competition with GB; high unemployment
9 million people before epidemic; 1 million deaths from starvation, diseases
(cholera, typhus, etc.)
1.5 million emigrants after epidemic; 5.5 million emigrants until WWI, many
to U.S. East Coast (e.g., Boston)
Seeds of Change
• By Henry Hobhouse
• “Five plants that transformed mankind”
• Chapters on: quinine, sugar, tea, cotton,
potato
• Interesting, informative, historical
Botany of Desire
• By Michael Pollan
– 4 desires: sweetness, beauty, intoxication,
control
– history of people manipulating plants - or is it
a history of plants manipulating people?
– focus on four plants: apples, tulips, marijuana,
& potatoes
Sweet potato
• Species: Ipomoea batatas (L.) Lam.
Family: Convolvulaceae
• Tropical perennial (from S. America) cultivated
as an annual in temperate climates
• Enlarged edible storage (tuberous) roots; lots of
beta-carotene & sweet taste
• 80% of world production in China, U.S. accounts
for 1% of production
• Two types
– Cream-to-light yellow colored flesh, non-sweet flavor,
dry texture
– Yellow or deep orange, moist texture, distinct flavor,
high sugar content (often called “yams”)
Sweet potato continued
• Warm-season crop
• Introduced to Europe (Spain) by Columbus
• Rich in CHO (more sugar & calories, less
starch, compared to white potato); rich in
certain vitamins, especially A (from betacarotene) & C
(true) Yams
• Dioscorea species; Dioscoreaceae (Yam family); a
monocot
• Old World tropical origin (W. Africa)
• Tubers (up 90 lbs); hard to harvest, so mostly
replaced by cassava
• ca. 20% starch; low in protein, vitamins (low in
carotene too), & minerals
• Tubers contain saponins, type of steroid
– Once used to make human sex hormones and cortisone
Several decades ago, when orangefleshed sweet potatoes were
introduced in the southern United
States, producers and shippers
desired to distinguish them from the
more traditional, white-fleshed types.
The African word nyami, referring to
the starchy, edible root of the
Dioscorea genus of plants, was
adopted in its English form, yam.
Yams in the U.S. are actually sweet
potatoes with relatively moist texture
and orange flesh. Although the terms
are generally used interchangeably,
the U.S. Department of Agriculture
requires that the label "yam" always
be accompanied by "sweet potato."
• “potato of the humid tropics”
• Poi, traditional dish of native
Hawaiians
• Corms are steamed, crushed,
made into a dough, and
allowed to ferment naturally
by microbes. Doughy paste
eaten with fingers or rolled
into small balls; main staple in
the traditional diet.
• Can be cooked similar to
potatoes (baked, steamed,
roasted, boiled) or processed
into flour, chips, breakfast
foods
Taro
THE POTATO OF THE HUMID TROPICS
Taro, dasheen, or cocoyam (Colocasia esculenta var. antiquorum)
ARACEAE, Arum Family
About 10% of the world's population uses taro or taro-like plants (Araceae) as a staple in
the diet, and for 100 million people this is an important daily food. The Colocasia taro is
a very common crop for wet soils in the humid tropics, especially in Southeast Asia, the
Pacific Basin, wet tropical Africa and Egypt, the West Indies, and certain areas of South
America; the yautias (Xanthosoma), close cousins of taro, are native to and grow mostly
in the New World. The chief food from these plants is the "corm," an erect, starchy,
underground stem, which grows to be over a foot long, but leaves are also consumed.
Taro has leaves that are 1 to 2 meters long with a long, erect petiole and an arrowshaped blade. Plants like this are sometimes called "elephant ear." The plants rarely
flowers and never set seed, so vegetative propagation via replanting portions of the
corm is the only way to grow this plant.
Some have speculated that taro and yautia were among the first of all cultivated plants,
because natives learned to eat the bottom portion of the corm and then replant the
leaves and top of the corm, so that they could return in ten months for a new crop.
Estimates are that taro was in cultivation in wet tropical India before 5000 B.C.
When Captain Cook discovered the Hawaiian Islands in 1778, the native population
(est. 300,000) lived chiefly on dasheen and sweet potatoes (Ipomoea batatas),
supplemented with things from the sea. Poi was traditionally prepared by removing
the corm "skin" and then pounding the white flesh on a board with a stone pounder
(pohaku ku'I) to make a thick paste, which was dried, diluted with water, kneaded,
and then aged. The infamous Polynesian poi may be fermented (first bacteria, then
yeast) or sometimes unfermented forms of this sticky dasheen paste, eaten with the
fingers or as small balls. Some Polynesians were said to consume up to 20 pounds
of poi per day!
Taro corms are roasted, boiled, or baked, and may be made into cakes. Heating is
necessary to remove an acrid, irritating property of the raw corm. In the Hawaiian
Islands, taro plant is eaten after thoroughly boiled to destroy the toxins; the leaf
(luau, also the name of the feast using taro leaves) must be boiled at least 45
minutes over low heat, whereas corms are boiled in a deep pot with salted water for
at least an hour or until soft.
Taro is similar to the Irish potato (Solanum tuberosum) in many properties, and is
sometimes called the "potato" of the humid tropics. In comparison with potato, taro
corm has a similar proportion of protein (1.5-3.0%), calcium, and phosphorus; it has
a trace of fat, and is rich in vitamins A and C. Moreover, taro is 98.8% digestible,
because it has very small starch grains fairly rich in amylose (20-25%), which breaks
down to sugar with human saliva. This type of carbohydrate is excellent for people
with digestive problems, so that taro flour is used in infant formulae and canned baby
foods and is good for people with allergies, such as lactose intolerance.
Manioc or Cassava
Euphorbiaceae: Manihot esculenta
• starchy staple in tropics; e.g.,
Africa, S. America, Asia
• Originated from north S. America
• Other names: yuca, mandioca
• large herbaceous shrub up to 10
feet; with tuberous roots like large
sweet potatoes in appearance
• Grown in warm climates
• fleshy roots contain poisonous
compounds (cyanogenic
glycosides - compounds that
liberate cyanide) that must be
removed before eating
• heat, drought, & pest tolerant;
also tolerates acid & high- Al soil
• 30% FW starch; <1% protein
detoxification
• peeling and grating the flesh causes HCN production
• squeeze the contents and get the maximum surface area
exposed to enzymes and to squeeze out some of the toxic
leachate
• pulp stands overnight and the remaining toxins are
removed by the heat of cooking the pulp or meal into cakes
• Other methods– Sometimes drying in the sun is enough to remove the cyanide gas;
it will disperse into the air as the manioc dries in the heat.
• sweet manioc is less toxic & can be merely boiled or baked,
but is more pest & disease susceptible compared to more
toxic bitter varieties
• purified starch for thickening agent
– tapioca are gelatinized pellets
Banana
Musa species; Musaceae (banana family)
• Common Names: Banana, Bananier Nain, Canbur,
Curro, Plantain
• Origin: SE Asia.
• Fruits (a berry): ovaries develop parthenocarpically
(w/o pollination) into clusters of fruits, called hands.
• cultivated types are seedless with just vestiges of
ovules visible as brown specks. Occasionally, crosspollination with wild types will result in a number of
seeds in a normally seedless variety.
• Propagated vegetatively, so genetic uniformity
• Both sweet & starchy (plantain) varieties
• Needs warm temps & lots of water; grown in tropics;
• A large herbaceous annual
New test speeds search for
12 March 2004 resistant bananas
In recent years, Panama disease has had a major impact on banana yields in
Africa, Asia and Australia, and is expected to spread to Latin America and the
Caribbean. ….The fungus that causes the disease, known as Fusarium
oxysporum, establishes itself in the soil and is virtually impossible to control with
chemicals….The current method of detecting which banana strains are
susceptible to the disease is time-consuming and laborious. It involves infecting
soil with the fungus, waiting for the plant to grow, and then cutting the plant at the
base of the stem to evaluate the extent of internal damage. …. The new test
takes just a few days to get results, and can be carried out on a single leaf. The
fungus is grown in the laboratory and applied to tiny perforations in harvested
banana leaves. After 48 hours, lesions of around 18 mm in length can be seen in
the leaves of susceptible plants, while leaves from resistant plants have much
smaller lesions of less than 7 mm. …. Ninety nine per cent of bananas found in
Western supermarkets belong to a single variety, Cavendish, a sterile clone that
is propagated by cuttings. The variety was initially adopted in the 1960s, when
Panama disease forced banana growers around the world to abandon previous
varieties. But now Cavendish bananas are being infected with a new virulent
strain of the fungus, called race 4, making it essential that new resistant strains
are developed.
Jerusalem artichoke
• Helianthus tuberosus (Asteraceae)
• Pilgrims named this staple with
regard to the “New Jerusalem” they
were carving out of the wilderness
• Weedy hardy easily-cultivated
perennial produces tubers
• 10% protein, 76% carbohydrate
inulin, no oil, no starch
– Inulin is digested into fructose, which is
1.5 x sweeter than sucrose
– folk remedy of diabetes
• Eat fresh, cooked or pickled
Lotus
(Nelumbo nucifera in Asia, N. lutea in N. America)
Family Nymphaeaceae
• Water Lily family
• Lotus roots are good stir-fried or steamed; but
they can also be boiled, baked, or braised
– Chinese traditionally serve them candied as a New
Year treat.
– Japanese like them fried in oil, then cooked in lemon
water. In India, hot pickles are made with them.
• leaves and the flowers are also used as food,
seeds are peeled and eaten
• husk leaves are used as the basis of medicinal
teas in China
The lotus (Nelumbo nucifera) is a fresh-water plant that grows in
semitropical climates. It originated in India and was brought to other
countries, ranging from Egypt to China, about 2,000 years ago. It is
cultivated extensively in Southeast Asia (mostly in China), primarily
for food, with much smaller amounts for herbal medicine. All parts of
the plant are utilized, but the primary reason for its current widespread
cultivation is to collect the rhizomes (sometimes referred to as roots)
and seeds. The whole plant is harvested in late summer when the seeds
have matured.
The rhizomes are a food used extensively in China and Japan, sold
whole or in cut pieces, fresh, frozen, or canned. They are consumed as
a vegetable, usually fried or cooked in soups. Japan is one of the
primary users of the rhizomes, representing about 1% of all vegetables
consumed there. Japan grows its own lotus but still has to import
18,000 tons of lotus rhizome each year, of which China provides
15,000 tons.
Arrow root
Maranta arundinacea; Family: Marantaceae
•
•
•
starchy product of a New World tropical tuber
arrowroot starch that you can find in health
food stores may actually be almost anything
from bananas, rice, potatoes, to starch from
almost any tropical root
used for thickening sauces; makes very
delicate sauces, and it thickens at a lower
temperature than corn starch
Arrowroot was introduced into European
culture by some of the early European
settlers of the New World, who learned of
it from the Arawak, the people who lived
in the Caribbean Islands (and who still
live in remote areas of Guiana, a region
of mainland South America due north of
Brazil). The Arawak named the plant aruaru, which meant literally "meal of
meals," indicating how highly they valued
the starchy food made from the arrowroot
tubers. The Arawak also used arrowroot
tubers to draw poison from wounds
inflicted by poisoned arrows, which is
where the name "arrowroot" apparently
came from in English, first recorded in
1696.
Breadfruit (Artocarpus altilis), a
nutritious starchy melon weighing
between two to five pounds was
looked upon as an excellent food
source for the African slaves in the
plantations of the Caribbean.
Although it is a fruit, it’s light
yellow flesh has the starchy
consistency of unripe potatoes
which makes it seem more like a
vegetable. As the breadfruit ripens
it softens to about the consistency
of a mango but without the
sweetness.
The reason for the name “breadfruit” is that when eaten before it is
ripe, breadfruit not only feels like fresh bread, but also tastes like it.
Not only are breadfruit trees in the Pacific prized for their fruits but
their wood is also highly valuable. In Hawaii, the wood of breadfruit
trees were made into fine quality canoes, drums, and surfboards. In
Guam and Samoa, the bark of the breadfruit trees were used for
making tapa cloth.
Cattail (Typha species);
Typhaceae
Food: The roots may be
ground into a flour. The
sticky sap between the
leaves is an excellent
starch and can be used
to thicken soups and
broths. The white
colored shoots at the
base of the leaf clusters
can be boiled or
steamed or sliced and
eaten raw in salads.