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Legumes

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The fruit (the pod) is 15 25 cm long in modern food cultivars. ... pinto beans refried beans in Mexican foods. white (haricot, navy) beans Boston baked beans ... – PowerPoint PPT presentation

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Title: Legumes


1
  • Legumes
  • Legumes are dicotyledonous plants in the family
    Fabaceae. They have in common a number of
    structural and functional characteristics
  • Their fruits are pods simple, dry fruits
    with (generally)
  • multiple embryos (seeds) attached to an
    elongated carpel
  • that dehisces (opens) along seams on two
    sides. Not all
  • legumes dehisce alfalfa (Medicago sativa)
    does not.
  • They are involved in a mutualistic association
    with nitrogen-
  • fixing bacteria (Rhizobium spp.) present in
    root nodules that
  • result in legumes having high levels of
    protein, as well as
  • adding available nitrogen to the soil
  • Their flowers are not radially symmetric, but
    bilaterally
  • symmetric.

2
Legumes are frequently divided into two groups
forage species like alfalfa, clover and vetch
that are eaten by grazing herbivores grain
species, cultivated for their seeds, like various
beans, peas, peanuts and lentils. This group
are also known as pulse crops. All have
high protein content. All add nitrogen to the
soil (90 million metric tons/yr).
3
  • Lets first consider beans
  • There are many types of beans, and taxonomic
    distinctions between them
  • broad bean (Vicia faba) is an Old World species
    that
  • originated in the Mediterranean area (or
    possibly Africa). It
  • was cultivated 6000 YBP. Since Im not a fan,
    here are some
  • of the health problems they can cause
  • favism caused by the presence of vicine and
    convicine in them. Individuals who are
    deficient in the titre of the enzyme glucose 6
    phosphate dehydrogenase (G6PDH) suffer from a
    hemolytic anemia
  • these beans have high tyramine, and should be
    avoided when taking MAO (monoamine oxidase)
    inhibitors
  • a health benefit they are rich in L-dopa,
    which is used to treat Parkinsons disease

4
Broad beans
Broad bean flowers
The fruit (the pod) is 15 25 cm long in modern
food cultivars. Pods contain 3 8 seeds, each
20 x 15 x 7.5 mm. Broad beans are eaten before
complete maturity, while young and tender.
5
  • Other dry beans (kidney, pinto, black, haricot)
    and some we consume with the enclosing carpel
    (green, string) are all varieties (cultivars) of
    a single species, Phaseolus vulgaris L.
  • These beans are originally from the Americas and
    were first cultivated in MesoAmerica. They are a
    staple food.

6
Nutritional content per 100g carbohydrates 60
g dietary fiber 25 g lipids 1
g protein 24 g B5 (pantothenic acid) 0.8 mg
(19 RDI) B9 (folic acid) 394 mg (99
RDI) Fe 8 mg (64) Mg 140 mg
(38) There is one health concern (that normally
doesnt apply) dry beans should be soaked, then
boiled for at least 10 minutes. They
(particularly red kidney beans) contain a lectin
phytohaemagglutinin, which can cause severe
gastric upset. What about flatulence? Caused by
complex sugars that are removed by soaking.
7
  • Compared to the dry beans, green and string beans
    provide less starch and protein, but more
    vitamins A and C.
  • Some uses
  • pinto beans refried beans in Mexican foods
  • white (haricot, navy) beans Boston baked beans
  • kidney beans chili, Louisiana creole dishes,
    southern U.S. red beans and rice
  • black (turtle) beans burritos, feijoada (a
    national dish of Brazil)
  • Lentils (Lens culinaris)
  • Originate in the Near East, and one of the first
    crops domesticated there. They are second only to
    soybeans in protein content 26. As a result
    they are very important in vegetarian diets.

8
The optical lens draws its name from the lentil,
because the seed has a lens shape. The largest
producer is India, but Canada is both a
significant producer and a large exporter. Of a
world total production of 3.2 million metric
tons, Canada (mostly Saskatchewan) produces about
520,000 tons, and exports around 400,000 tons.
9
This is a map of lentil growing areas (area of
origin in red)
In India lentils are boiled to a thick stew-like
consistency and mixed with oil and spices to make
dal. In Ethiopia they are roasted then boiled to
a very thick, stew-like consistency and mixed
with berber sauce (long-cooked cayenne pepper,
onions and water). In Europe and North America
they are added to soups.
10
  • A different genus of beans, Vigna, includes
    black-eyed peas (V. unguiculata), mung beans (V.
    radiata) and black gram (V. mungo). Growing areas
    and uses differ
  • Black-eyed peas are originally native to Africa,
    but are now grown in southern Asia, Africa, the
    West Indies, and the southern U.S. Along with
    peanuts, George Washington Carver promoted
    cultivation of this bean.
  • In the south the traditional dish is called
    hoppin John, and consists of black-eyed peas
    and pork (jowls, fatback or hocks). It is also
    traditionally served with greens (mustard or
    collard) and cornbread.
  • In the West Indies, the traditional dish is rice
    and beans.

11
mung beans are native to India, even the name
comes from a word in Hindi. In Chinese cuisine
they may be eaten whole or as bean sprouts. They
are also ground up to produce bean thread (or
cellophane) noodles. Black gram (or black
turtle bean) is originally from India, where it
is still used to make urad dal. It is also ground
to make various dishes. Though it is late in the
story of beans, its worth mentioning that beans
are valuable in a diabetic diet.
12
Two more bean genera first the chick pea or
garbanzo bean (Cicer arietinum) chick peas are
tropical and need a lot of rain (400 mm). There
are two types Desi-type is a smaller seed with a
rougher coat, and closely resembles
archaeological evidence of origin. It is now
grown in India, Ethiopia and Mexico, but
originated in the fertile crescent (southeast
Turkey). This type has a notably low glycemic
index (particularly good for diabetics). In India
it is ground as a coating flour and roasted as a
snack. Kabuli-type is grown around the
Mediterranean and Afganistan. This is the type
used in the mid-East to make falafal and
hummus. Chickpeas are a good source of zinc and
protein. They are also very high in dietary
fiber. They are low in fat, and most of the fat
content is monounsaturated.
13
There are other legumes than beans. Peas (Pisum
sativum), due to their rapid growth (they, like
the beans, are annual plants) and ability to
control parentage, were the plants used by Gregor
Mendel to develop the basic laws of
genetics. There are many types green peas, split
peas, and snow peas (with edible pods) among
them. Unlike many beans, that are tolerant of
heat and drought, peas are cool season plants.
The cultivars you see grown around here are among
the many that grow best at a temperature of about
13C.
14
Comparing dry split peas and fresh peas, there
are clear differences in nutritional value (per
100 g) Green peas split peas Carbohydrates
14.5 g 60 g Fiber 5.1 g
26.1 g Protein 5.4 g 25 g Vitamin
C 40 mg (67) ----- Vitamin B1
----- 0.7 mg (54) Pantothenic acid (B5)
----- 1.7 mg (34) Folic acid (B9)
----- 274 ?g (69) In Asia, dry peas are
roasted, salted and eaten as a snack. In England,
dry peas are rehydrated and mashed as mushy
peas
15
Soybeans (Glycine max) are native to and were
first cultivated in China about 5,000 years ago.
They were brought to Europe in the 17th century.
They were then brought to North America only
about a century later, but not widely grown until
the 1920s.
16
Soybeans are very nutritious. In dry soybeans,
protein is about 40 of seed weight and highly
unsaturated (good) oil about 20. The protein
contains all essential amino acids. Soybean oil
(along with canola oil) are the only vegetable
sources for omega-3 fatty acids. Soybeans contain
isoflavones (phytoestrogens) that may either aid
in cancer prevention or cause cancers (an active
debate). These same isoflavones have been
suggested to reduce cholesterol. The FDA and
American Heart Association think this is only
meaningful for individuals with very high
cholesterol. Unlike many kinds of protein, that
in soybeans is heat stable, so that soy products
can be cooked at high temperatures without
destroying protein value.
17
  • Soybeans also contain useful amounts of many
    vitamins and minerals.
  • Soybeans are used in many different ways and
    products. Among them
  • fermented to make soy sauce
  • extracted to make soy milk (for the lactose
    intolerant)
  • made into a cheese we call tofu
  • which is then used in many products, e.g.
    tofutti
  • boiled green as edamame (Japanese additive to
    dishes)
  • made into a paste with rice and fermented (miso)
    used in Japanese soups
  • sprouted for use as an alternative to mung beans
  • made into textured vegetable protein (TVP) added
    as a high protein extender to many meat
    products
  • extracted for soy oil used in many products (and
    the waste dry protein is then used in animal
    feed)

18
  • lecithin is an additive in chocolate and many
    baked goods. Its a lipid extracted from
    soybeans.
  • It should be obvious that soybeans are widely
    used, and I havent even mentioned industrial
    uses for soy oil.
  • One possible concern most (89) of the soybeans
    now grown in the U.S. are GMO. In 1995 Monsanto
    introduced a Roundup Ready soybean that, unlike
    previous genotypes, was not killed by
    glyophosphate, the active ingredient in the
    herbicide. The gene that made the soybean
    resistant came from a bacterium, Agrobacterium
    sp. The gene, EPSP (5-enolpyruvyl shikimic
    acid-3-phosphate synthase) is also in soybeans,
    but in an alternative allele that leaves
    natural soybeans sensitive and vulnerable. Like
    it or not, were all consuming GMO foods through
    this transgenic plant.

19
Lastly, peanuts (Arachis hypogaea) are native to
South America (probably Argentina or Bolivia). It
gets its species name from the strange way its
fruit matures. After pollination, the fruit
develops into a legume pod 3 to 7 cm (1 to 2
inches) long containing 1 to 3 (rarely 4) seeds,
which forces its way underground to mature. You
know, because you have to crack the pod open,
that this fruit, unlike most other legumes, is
indehiscent (doesnt open).
20
Raw peanuts are very nutritious. Contents (per
100 g) are Carbohydrate 20.91 g dietary
fiber 8.7 g protein 25.09 g fat
(oil) 47.58 g 20 or more of RDIs of thiamin,
riboflavin, niacin, pantothenic acid, folic
acid, B6, Mg, P, Zinc, and less of many
others How many ways do we use them? Give George
Washington Carver credit for a large number of
the literally 100s (300) of ways. A short list
would include peanut butter, roasted snacks, as
beer nuts, in candies, boiled Peanut oil is
widely used in cooking because it has the highest
smoke and flash point of all vegetable oils.
21
  • Peanut oil is used in the manufacture of paint,
    varnish, lubricating oil, leather dressings,
    furniture polish, insecticides, and
    nitroglycerin. Soap is made from saponified
    peanut oil, and many cosmetics contain peanut oil
    and its derivatives.
  • Peanut shells are put to use in the manufacture
    of plastic, wallboard, abrasives, and fuel. They
    are also used to make cellulose (used in rayon
    and paper) and mucilage (glue).
  • Problems with peanuts
  • peanuts are considered an incomplete protein,
    with relatively low amounts of the essential
    amino acids lysine, cystine and methionine
  • peanuts are also an unbalanced source of fat
    because they are devoid of required omega-3
    fatty acids
  • peanuts may be contaminated with the mold
    Aspergillus flavus which produces aflatoxin, a
    carcinogen

22
  • some people have severe allergic reactions to
    peanuts. Exposure can cause fatal anaphylactic
    shock. It is now believed that the underlying
    mechanism is a result of the tendency in North
    America to roast peanuts. Roasting makes
    the allergin, Ara h2, inhibit the digestive
    enzyme trypsin more strongly, so that it
    doesnt get digested. That also protects one of
    the other strong allergins, Ara h1, from
    digestion. as well.
  • In Asia, where peanuts are not roasted, the
    occurrence of peanut allergies is very rare.
  • Major producers are the India, China (both almost
    entirely for the oil), U.S., Argentina, Sudan,
    Senegal, and Brazil. We are major importers.

23
Apparent Group topics Cacao/chocolate Teas
(green/black/white/herbal) Fruit crops
(dates/pomegranates/figs/durian) Coffee
(arabica/robusta/fair trade) Ginger/ginger
root Plants as drugs (marijuana/cocaine/painkiller
s/cancer cures) Peanuts and peanut
allergies GMO Cinnamon Plants as herbal medicines
(ginseng/aloe vera)
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