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. Slide 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). Slide 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 Slide 4 Broad
bean flowers Broad beans 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. Slide 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. Slide 6
Nutritional content per 100g: carbohydrates60 g dietary fiber25 g
lipids 1 g protein24 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. Slide 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. Slide 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. Slide 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. Slide 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. Slide 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. Slide 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.
Slide 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. Slide 14 Comparing dry split peas and fresh peas, there are
clear differences in nutritional value (per 100 g): Green peassplit
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 B 1 ----- 0.7 mg (54%)
Pantothenic acid (B 5 ) ----- 1.7 mg (34%) Folic acid (B 9 ) -----
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
Slide 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 17 th century. They were then brought to North
America only about a century later, but not widely grown until the
1920s. Slide 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. Slide 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) Slide 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. Slide 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). Slide 20 Raw peanuts are very
nutritious. Contents (per 100 g) are: Carbohydrate20.91 g dietary
fiber8.7 g protein25.09 g fat (oil)47.58 g 20% or more of RDIs of
thiamin, riboflavin, niacin, pantothenic acid, folic acid, B 6, 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. Slide 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 Slide 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.
Slide 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/painkillers/cancer cures) Peanuts and peanut
allergies GMO Cinnamon Plants as herbal medicines (ginseng/aloe
vera)