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Cereal Crops

Cereal Crops. Major, minor, wild and Pseudo-. Wheat. Triticum- more than 10-20 species distributed through Eastern Mediterranean to Iran. Temperate crop Complex ancestry and were first domesticated in the Near east some time before 7000BC. Evolution through polyploidy

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Cereal Crops

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  1. Cereal Crops Major, minor, wild and Pseudo-

  2. Wheat • Triticum- more than 10-20 species distributed through Eastern Mediterranean to Iran. • Temperate crop • Complex ancestry and were first domesticated in the Near east some time before 7000BC. • Evolution through polyploidy • Diploid – T.monococcum(einkorn) • Tetraploid – T.dicoccon (emmer) • Hexaploid – T.aestivum (common bread wheat • T.durum (durum, flint, hard or macaroni)

  3. Wheat • Most important are bread and durum wheat • Prehistoric cultivars are being revived • Emmer and einkorn – high amylose and not suitable for leavened bread • Two main proteins- glutenin and gliadin which makes the dough elastic when mixed with water.

  4. Chemistry • 82-94% of the grain is endosperm • Starch 90% and proteins 6-9% • 6% - embryo rich in proteins and yield fatty oil. • Chief proteins are glutelins and gliadins which contain all essential amino acids except lysine and threonine. • Whole wheat – bran (pericarp and integumants) 11-15% proteins, vitB and minerals

  5. Cooking • Dough mixed with water and yeast. • Forms gluten complex produces loaves • Yeast carry out fermentation and produces CO2 and dough rises. • Baking sets the dough by • drying the starch • denaturing proteins and • Killing the yeast

  6. Wheat • Two major events impacted wheat production • Growing rust (Puccinia garminis) resistant varieties and • Modern industrial flour mills. • Flours • Whole or graham flour: 100% grain, nothing added or removed • Brown flour: 85% grain • White flour: 75-78% grain with bran and germ removed. • White flour has longer shelf life than brown due to oils

  7. Rice • Oryza – 20 species distributed in tropical and subtropical areas, growing in humid forests and open swamps • Oryza sativa; O.glaberima; and O.barthii • Irrigation began in china; 9000 – 12000 years • Second most important crop in terms of global population. • Usually associated with low income and poverty but considered a symbol of fertility • 1.7 billion people use it

  8. Rice • Needs hot, moist climate and large quantities of water to grow well • Two types • Upland rice – no need of standing water • Paddy rice – grows in standing water • Unhusked grain – known as paddy

  9. Rice • While cooking gelatinzes and cell wall ruptures. • Two to three races • indica type – long-grain; dry and separate • Japonica or sativa – short grain soft and slightly gleuy • Javanica – indochina; equatorial plane, gleuy • Gelatinous temperature and amylose content. • High amylose – dry and flaky • Low amylose – sticky and moist • Mainly contains starch, 12% proteins • Glutelins, albumins, prolines • Lack lysine and theornine • Removing bran and germ removes thiamine - beriberi

  10. Maize • Zea mays • Domesticated in Central America; only cereal used as vegetable; largest cereal • Ancestor – mexican teosinte • Flowers unisexual • 70% endosperm and 11% embryo • 11% protein in the aleuron layer • Germ yields glutelin while aleuron layer has zein • Zein – rich in leucine but lack lysine and tryptophan • Excess leucine prevent conversion of tryptophan to niacin - pellagra

  11. Maize has hard vitreous and soft floury endosperm Types Flint – mostly hard endosperm – round when dry Dent –high floury center – shrinks when dry Soft – mostly soft endosperm waxy corn Maize

  12. Barley • Hordeum vulgare • A temperate plant; domesticated plant • A major animal feed and brewing • Has low gluten and cannot be leavened • Has beta glucan – lower blood cholesterol • Reduces colon cancer

  13. Sorghum • Sorghum bicolor – tropical Africa. • Major food in India, and Africa where leavened bread is not important • Very versatile crop • Black and brown sorghum has polyphenol such as condensed

  14. Oats • Avena sativa • Has elongated caryopsis • Two aleurone layers • 12-13% proteins; 4-5% oils; 66-77% CHO and 12-15% crude fiber (reduce blood sugar by reducing absorption) • Oats used more for medicinal value • Has all essential amino acids • They are heat processed to denature enzyme

  15. Millets • General term for several small seeded grain • Pearl millets: Pennisetum glaucum • Most drought resistant • High proteins and ash content

  16. Rye • Secale cereale • Feed cereal • Alcoholic drinks • Infections – ergot • Has pentosans not starch – does not disintegrates and gelatinization – soft crumbs • Usually mixed with wheat flour

  17. Triticale • Intergeneric hybrid • Triticum and Secale

  18. Pseudocerals • Herbaceous dictolydons • Amaranthus – new world; mexico –Incas and Aztecs; puffed or milled, 30% proteins; squalene – precursor of steroids triterpenoids • Chenopodium – grains of chenopods. New and old world; essential amino acid lysine; need cortication • Fagopyrum: Buckwheat; China; high protein; dermatitis if not decorticated • Have salt soluble proteins and water soluble albumins • No gluten

  19. Sources of Sugar • Sucrose is the major source of sweetening principle • Artificial sweetener are introduced due to health problems, such as diabetes, obesity.. • Carbohydrates • Simple sweet; out of more the 60 monosaccharides, fructose is most sweet; sugar alcohols, amines and acids are sweet. • Complex-polymer not so sweet

  20. Sugarcane • Saccharum officinarum L.(Poaceae) • 12-15% sucrose, glucose and fructose • 12-20% fiber • .3-.4% nitrogenous compounds • Fats, waxes, acids and pectins • Sugarcane juice: acotinic acid, citric and malic acids; vit B, D and enzymes like invertase and oxidases

  21. Sugar beet • Beta vulgaris var. rapa • Roots have upto20% sugar • Betaine is commercially extracted • Waste has galacturonic acid – used to synthesize vit c

  22. Maple • Acer sacchrum and A.nigrum. • The sap is tapped by cutting incisions on the sapwood. • The extract is boiled and poured into molds

  23. Palm sugar • Coconut – Cocos nucifera • Wild date palm – Phoenix sylvestris

  24. Sweetening principles from plantsTerpenes • Licorice – Glycrrhiza glabra (Fabaceae) • Tripterpenoids – glycyrrhizin is a saponin. 50 times sweeter than sugar • Looses sweetness after hydrolysis • Expectorant, laxative and antiinflammatory

  25. Terpenes • Stevia

  26. Proteins • Discoreophyllum cumminsii Diels –Menispermaceae • Perennial dioecious twiner; produces small red berries. • Mucilage inside the berries are extremely sweet • Monellin -9,000 times sweeter than sucrose • A peptide with 91 amino acids • Not heat tolerant • Tropical W. Africa

  27. Proteins • Thaumatococcus danielli Benth. (Marantaceae) • Rhizomatous herb –tropical Nigeria • Rarely fruits – seeds are very sweet • Taste modifier • Thaumatin - protein

  28. Glycoprotein • Synsepalum dulcifolium (Sapotaceae) – taste modifier

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