Cereal Crops.ppt

1、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 Diploid T.monococcum(einkorn) Tetr

2、aploid T.dicoccon (emmer) Hexaploid T.aestivum (common bread wheatT.durum (durum, flint, hard or macaroni),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

3、 which makes the dough elastic when mixed with water.,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 b

4、ran (pericarp and integumants) 11-15% proteins, vitB and minerals,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,Wheat,T

5、wo 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% grainWhite flour: 75-78% grain with bran and germ removed. White flour has longer shel

6、f life than brown due to oils,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 associate

7、d with low income and poverty but considered a symbol of fertility 1.7 billion people use it,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,Rice,While cooking ge

8、latinzes 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 c

9、ontains starch, 12% proteins Glutelins, albumins, prolines Lack lysine and theornine Removing bran and germ removes thiamine - beriberi,Maize,Zea mays Domesticated in Central America; only cereal used as vegetable; largest cereal Ancestor mexican teosinte Flowers unisexual 70% endosperm and 11% embr

10、yo 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,Maize,Maize has hard vitreous and soft floury endosperm Types Flint mostly hard endosperm rou

11、nd when dry Dent high floury center shrinks when dry Soft mostly soft endosperm waxy corn,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,Sorghum,Sorghum bi

12、color 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,Oats,Avena sativa Has elongated caryopsis Two aleurone layers 12-13% proteins; 4-5% oils; 66-77% CHO and 12-15% crude fiber (reduc

13、e blood sugar by reducing absorption) Oats used more for medicinal value Has all essential amino acids They are heat processed to denature enzyme,Millets,General term for several small seeded grain Pearl millets: Pennisetum glaucum Most drought resistant High proteins and ash content,Rye,Secale cere

14、ale Feed cereal Alcoholic drinks Infections ergot Has pentosans not starch does not disintegrates and gelatinization soft crumbs Usually mixed with wheat flour,Triticale,Intergeneric hybrid Triticum and Secale,Pseudocerals,Herbaceous dictolydons Amaranthus new world; mexico Incas and Aztecs; puffed

15、or milled, 30% proteins; squalene precursor of steroids triterpenoidsChenopodium 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 gl

16、uten,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-

17、polymer not so sweet,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,Sugar beet,Beta vulg

18、aris var. rapa Roots have upto20% sugar Betaine is commercially extracted Waste has galacturonic acid used to synthesize vit c,Maple,Acer sacchrum and A.nigrum. The sap is tapped by cutting incisions on the sapwood. The extract is boiled and poured into molds,Palm sugar,Coconut Cocos nucifera Wild d

19、ate palm Phoenix sylvestris,Sweetening principles from plants Terpenes,Licorice Glycrrhiza glabra (Fabaceae) Tripterpenoids glycyrrhizin is a saponin. 50 times sweeter than sugar Looses sweetness after hydrolysis Expectorant, laxative and antiinflammatory,Terpenes,Stevia,Proteins,Discoreophyllum cum

20、minsii 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,Proteins,Thaumatococcus danielli Benth. (Marantaceae) Rhizomatous herb tropical Nigeria Rarely fruits seeds are very sweet Taste modifier Thaumatin - protein,Glycoprotein,Synsepalum dulcifolium (Sapotaceae) taste modifier,