1. LEGUMES

2. Legume Family - Fabaceae
All types of beans and peas
Soybean, peanut, alfalfa, clover
Also includes various trees such as black locust, redbud
One of the largest dicot families - 13,000 species
Ranks right behind grasses in human impact

3. Family characteristics
Five-petalled irregular flower with bilateral symmetry
Fruit is a legume (dry dehiscent fruit - two lines of dehiscence) with one row of seeds
Seeds contain two large cotyledons

4. Legume flower Irregular flower with bilateral symmetry
Often butterfly-shaped

6. Legume seeds Important food staple worldwide
Rich in both oil and protein
Higher in protein than any other food plants
Close to animal meat in protein quality
Often called "poor man's meat"

7. Legumes and nitrogen-fixing bacteria
High protein correlated with root nodules which contain nitrogen-fixing bacteria
convert atmospheric nitrogen to useful form
Because of this legumes enrich the soil
Farmers often rotate legumes with crops that deplete soil nitrogen (soybean & corn)
"Green manure" crops plowed sometimes
Reduces need for fertilizers - legumes can be cultivated worldwide - even in poor soils

8. Nitrogen cycle Nitrogen Nitrogen gas (N2) about 79% of the air
essential elements for all living organisms
major component of amino acids, proteins, nucleic acids
Nitrogen gas (N2) about 79% of the air
most living organisms cannot use this form of nitrogen

9. Nitrogen-fixing bacteria
Certain bacteria and cyanobacteria have ability to reduce nitrogen (N2) gas to ammonium NH4+
cells can convert NH4+ to compounds
called nitrogen-fixation
organisms are called nitrogen-fixing

10. Nitrogen-fixing organisms
Some bacteria and some cyanobacteria
Some live freely in the soil
Most are found in symbiotic associations in the root nodules of legumes
Azolla is known to have a symbiotic association with a nitrogen-fixing cyanobacterium

11. Non-legume plants
Must rely on the nitrogen compounds present in the soil
During decomposition microorganisms break down proteins and other nitrogen-containing molecules into ammonium NH4+

12. Nitrogen compounds in soil
Some plants take up ammonium directly
Bacteria in the soil quickly convert ammonium to nitrite (NO2) and then nitrate - (NO3)
Nitrate is the form of nitrogen usually absorbed by plants
Fertilizer contain a mixture of both ammonium and nitrate

13. Nitrogen Cycle Non-legume plants bacteria NO3 NH4 NO2 bacteria

14. Other sources of nitrogen
Burning fossil fuels, volcanic activity, and lightning combine nitrogen and oxygen into NO2 and NO3
These are washed into the soil by rain and contribute to the nitrogen cycle
Denitrifying bacteria actually break down ammonium and nitrates returning nitrogen gas to the atmosphere

15. Legume food crops
Cultivated for thousands of years in both the Old World and New World
seeds easily harvested
seeds low water content and easily stored for long periods of time
These features plus their high protein content and ease in growing make them ideal crops

16. Beans and peas -- Pulses
Some of the oldest and most common food crops
Good source of protein average about 25% for beans and 21% for peas
Traditionally cultivated for dry seeds
Some varieties today have edible pods
Beans warm season annuals
Peas grown during the cooler seasons

17. Common Edible Beans & Peas
Black-eyed peas
Butter beans
Chick peas
Fava (broad) beans
Green beans
Green peas
Kidney bean
Lentils
Lima beans
Mung beans
Navy bean
Pinto beans
Snow peas
Split peas
Wax bean

18. Peanuts Also called goobers and groundnuts Native to South America
Time of domestication is unknown
gold and silver peanut-shaped jewelry dicovered in Peru in the tomb of a Moche warrior priest
peanut played a prominent role in the ancient Moche civilization
Carbon dating of tomb A.D.

19. Sixteenth century
Spanish explorers discovered peanuts in South America and took to Europe
Trading introduced peanuts to Africa where it became widely cultivated
The slave trade brought the peanut to North America
Today a staple crop in the south grown in Georgia, North Carolina, Texas, Alabama, Oklahoma and Virginia

20. Peanut - Arachis hypogea
Unusual plant
After pollination the flower stalk grows downward pushing the developing fruit into the soil
Fruit matures underground - typically with two seeds (peanuts)

21. Nutrition Highly nutritious with 45-50% oil and 25-30% protein
Over one billion pounds per year consumed in the US
Mainly as a snack food, in candy, and in peanut butter
Half the U.S. crop is used to make peanut butter

22. Peanut butter
First developed by a St. Louis physician in the 1890's as a nutritious and easily digested food for invalids who had difficulty chewing
Consume enough peanut butter each year to “fill the Grand Canyon”

23. Peanut oil
Found in margarine, shortening, salad dressing, and cooking oil
Soaps, cosmetics, and shaving cream
Industrial products such as plastics and paints
Pressed cake that remains after the extraction of oil is used as a high protein livestock feed

24. Versatility of the peanut
George Washington Carver ( )
Developed over 300 food and industrial uses for the peanut
Encouraged its cultivation in the South
Revitalized Southern agriculture exhausted by years of cotton cultivation
Also introduced other soil-enriching legumes like soybean

25. Soybean - Glycine max
Relatively new to the West but used in the Orient for centuries
It was considered one of the sacred crops of the ancient Chinese
Domesticated in northern China at least 3000 years ago

26. History in North America
Introduced in late 18th or early 19th century
Little interest until the 1920's
Today U.S. - world's leading producer
Often called the "Cinderella crop"
Reasons: versatility of the soybean and its suitability for growing in the corn belt region

27. Nutritional value of soybeans
One of the richest foods with 13-25% oil and 30-50% protein
Higher protein content than beef
Although originally used solely as animal feed, the soy protein is used more and more in the human diet

28. Food use of soybean
Since ancient times in Asia, soybeans have been consumed in hundreds of different ways
Not edible raw
Cooked they can be eaten whole
Often made into a paste, curd, or "milk"

29. Soy Products Soy sauce Soy milk
Traditionally made by fermenting soybeans in brine but today some synthetic
Soy milk
Beans soaked in water and pureed
Mixture is heated and the liquid poured off as soy milk
Non-dairy substitute for milk and baby formula (for lactose intolerant) individuals

30. Tofu Made from the curds of soy milk
Extremely versatile and used in main dishes in Japanese and Chinese meals
Made into cheeses, sour cream, and other imitation dairy products
Ice cream-like desert - Tofutti

31. Soy flour
After the extraction of oil, the meal that remains can be made into flour
Can be mixed with wheat flour in a variety of bread, pasta, baked goods, and breakfast foods
Replacing just a small fraction of the wheat flour with soy flour significantly improves the protein content

32. Other soybean foods
Miso - (from Japan) prepared from soybeans, salt, and rice; fermented by fungi for a several months and then ground into a paste and used as a spread, in soups, etc
Tempeh- (from Indonesia) fermented soybean cakes made by inoculating parboiled soybeans with a fungus and allowing it to grow for a few days. The fungal mycelium binds the soybeans together into a cake which can be sliced and cooked in various ways

33. More Soy Products Textured vegetable protein
Produced by spinning the soy protein into long slender fibers
Picks up flavors from other substances
Made into imitation meats and used as meat extenders
Lecithin - common food additive
Lipid extracted from soybeans
Stabilizes and extends the shelf life
Added to packaged foods - cake mixes, instant beverages, whipped toppings, and salad dressings

34. Soybean oil Food uses Industrial uses
Cooking oil, salad oil, margarine, shortening, and prepared salad dressings
Americans consume almost 6 gallons per year
Industrial uses
Paints, inks, soaps, cosmetics, biodiesel fuel
Soybean-based "plastic" car body built by Henry Ford in 1940
Ford's commitment to the soybean was so great that at one point he stated his goal was to "grow cars rather than mine them"

35. Other legumes of interest
Forage plants - alfalfa and clover
Super tree - Leucaena leucocephala
tropical tree that is one of the fastest growing species of woody plants for fire wood, wood pulp, and enriching the soil
Beans of the future:
Winged bean - all parts of plant are edible - pod, seeds, leaves, flowers, root
Tepary bean - adapted to arid tropical areas

36. Summary
Legumes are second only to the cereals in their importance in human nutrition and are an excellent source of high quality protein
Nitrogen fixation is important for generating nitrogen compounds that can be used by plants
Soybean has been transformed into a variety of food products and is increasing its role in the human diet