2Legume Family - Fabaceae All types of beans and peasSoybean, peanut, alfalfa, cloverAlso includes various trees such as black locust, redbudOne of the largest dicot families - 13,000 speciesRanks right behind grasses in human impact
3Family characteristics Five-petalled irregular flower with bilateral symmetryFruit is a legume (dry dehiscent fruit - two lines of dehiscence) with one row of seedsSeeds contain two large cotyledons
4Legume flower Irregular flower with bilateral symmetry Often butterfly-shaped
6Legume seeds Important food staple worldwide Rich in both oil and proteinHigher in protein than any other food plantsClose to animal meat in protein qualityOften called "poor man's meat"
7Legumes and nitrogen-fixing bacteria High protein correlated with root nodules which contain nitrogen-fixing bacteriaconvert atmospheric nitrogen to useful formBecause of this legumes enrich the soilFarmers often rotate legumes with crops that deplete soil nitrogen (soybean & corn)"Green manure" crops plowed sometimesReduces need for fertilizers - legumes can be cultivated worldwide - even in poor soils
8Nitrogen cycle Nitrogen Nitrogen gas (N2) about 79% of the air essential elements for all living organismsmajor component of amino acids, proteins, nucleic acidsNitrogen gas (N2) about 79% of the airmost living organisms cannot use this form of nitrogen
9Nitrogen-fixing bacteria Certain bacteria and cyanobacteria have ability to reduce nitrogen (N2) gas to ammonium NH4+cells can convert NH4+ to compoundscalled nitrogen-fixationorganisms are called nitrogen-fixing
10Nitrogen-fixing organisms Some bacteria and some cyanobacteriaSome live freely in the soilMost are found in symbiotic associations in the root nodules of legumesAzolla is known to have a symbiotic association with a nitrogen-fixing cyanobacterium
11Non-legume plantsMust rely on the nitrogen compounds present in the soilDuring decomposition microorganisms break down proteins and other nitrogen-containing molecules into ammonium NH4+
12Nitrogen compounds in soil Some plants take up ammonium directlyBacteria in the soil quickly convert ammonium to nitrite (NO2) and then nitrate - (NO3)Nitrate is the form of nitrogen usually absorbed by plantsFertilizer contain a mixture of both ammonium and nitrate
14Other sources of nitrogen Burning fossil fuels, volcanic activity, and lightning combine nitrogen and oxygen into NO2 and NO3These are washed into the soil by rain and contribute to the nitrogen cycleDenitrifying bacteria actually break down ammonium and nitrates returning nitrogen gas to the atmosphere
15Legume food cropsCultivated for thousands of years in both the Old World and New Worldseeds easily harvestedseeds low water content and easily stored for long periods of timeThese features plus their high protein content and ease in growing make them ideal crops
16Beans and peas -- Pulses Some of the oldest and most common food cropsGood source of protein average about 25% for beans and 21% for peasTraditionally cultivated for dry seedsSome varieties today have edible podsBeans warm season annualsPeas grown during the cooler seasons
18Peanuts Also called goobers and groundnuts Native to South America Time of domestication is unknowngold and silver peanut-shaped jewelry dicovered in Peru in the tomb of a Moche warrior priestpeanut played a prominent role in the ancient Moche civilizationCarbon dating of tomb A.D.
19Sixteenth centurySpanish explorers discovered peanuts in South America and took to EuropeTrading introduced peanuts to Africa where it became widely cultivatedThe slave trade brought the peanut to North AmericaToday a staple crop in the south grown in Georgia, North Carolina, Texas, Alabama, Oklahoma and Virginia
20Peanut - Arachis hypogea Unusual plantAfter pollination the flower stalk grows downward pushing the developing fruit into the soilFruit matures underground - typically with two seeds (peanuts)
21Nutrition Highly nutritious with 45-50% oil and 25-30% protein Over one billion pounds per year consumed in the USMainly as a snack food, in candy, and in peanut butterHalf the U.S. crop is used to make peanut butter
22Peanut butterFirst developed by a St. Louis physician in the 1890's as a nutritious and easily digested food for invalids who had difficulty chewingConsume enough peanut butter each year to “fill the Grand Canyon”
23Peanut oilFound in margarine, shortening, salad dressing, and cooking oilSoaps, cosmetics, and shaving creamIndustrial products such as plastics and paintsPressed cake that remains after the extraction of oil is used as a high protein livestock feed
24Versatility of the peanut George Washington Carver ( )Developed over 300 food and industrial uses for the peanutEncouraged its cultivation in the SouthRevitalized Southern agriculture exhausted by years of cotton cultivationAlso introduced other soil-enriching legumes like soybean
25Soybean - Glycine maxRelatively new to the West but used in the Orient for centuriesIt was considered one of the sacred crops of the ancient ChineseDomesticated in northern China at least 3000 years ago
26History in North America Introduced in late 18th or early 19th centuryLittle interest until the 1920'sToday U.S. - world's leading producerOften called the "Cinderella crop"Reasons: versatility of the soybean and its suitability for growing in the corn belt region
27Nutritional value of soybeans One of the richest foods with 13-25% oil and 30-50% proteinHigher protein content than beefAlthough originally used solely as animal feed, the soy protein is used more and more in the human diet
28Food use of soybeanSince ancient times in Asia, soybeans have been consumed in hundreds of different waysNot edible rawCooked they can be eaten wholeOften made into a paste, curd, or "milk"
29Soy Products Soy sauce Soy milk Traditionally made by fermenting soybeans in brine but today some syntheticSoy milkBeans soaked in water and pureedMixture is heated and the liquid poured off as soy milkNon-dairy substitute for milk and baby formula (for lactose intolerant) individuals
30Tofu Made from the curds of soy milk Extremely versatile and used in main dishes in Japanese and Chinese mealsMade into cheeses, sour cream, and other imitation dairy productsIce cream-like desert - Tofutti
31Soy flourAfter the extraction of oil, the meal that remains can be made into flourCan be mixed with wheat flour in a variety of bread, pasta, baked goods, and breakfast foodsReplacing just a small fraction of the wheat flour with soy flour significantly improves the protein content
32Other soybean foodsMiso - (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, etcTempeh- (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
33More Soy Products Textured vegetable protein Produced by spinning the soy protein into long slender fibersPicks up flavors from other substancesMade into imitation meats and used as meat extendersLecithin - common food additiveLipid extracted from soybeansStabilizes and extends the shelf lifeAdded to packaged foods - cake mixes, instant beverages, whipped toppings, and salad dressings
34Soybean oil Food uses Industrial uses Cooking oil, salad oil, margarine, shortening, and prepared salad dressingsAmericans consume almost 6 gallons per yearIndustrial usesPaints, inks, soaps, cosmetics, biodiesel fuelSoybean-based "plastic" car body built by Henry Ford in 1940Ford's commitment to the soybean was so great that at one point he stated his goal was to "grow cars rather than mine them"
35Other legumes of interest Forage plants - alfalfa and cloverSuper tree - Leucaena leucocephalatropical tree that is one of the fastest growing species of woody plants for fire wood, wood pulp, and enriching the soilBeans of the future:Winged bean - all parts of plant are edible - pod, seeds, leaves, flowers, rootTepary bean - adapted to arid tropical areas
36SummaryLegumes are second only to the cereals in their importance in human nutrition and are an excellent source of high quality proteinNitrogen fixation is important for generating nitrogen compounds that can be used by plantsSoybean has been transformed into a variety of food products and is increasing its role in the human diet