Food chem 14 pics

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    Egg proteins have been the subject of extensive investigation and much is known about them
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    • Ovalbumin is a globular phosphoglycoprotein with a molecular weight of about 45,000 daltons
    • It has 4 SH groups and 2 disulphide linkages and is readily denatured by surface forces, but not by heat
    • Responsible for meringue (foam) forming properties of egg white
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    Lysozyme- a low m olecular weight basic protein which is capable of hydrolyzing the cell walls of bacteria- considered a bacterial defence mechanism agains organisms that penetrate the egg shell
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    • Egg yolk can be split into two major fractions by high speed centrifugation into a higher density aqueous plasma fraction and a lower density lipidic granular fraction
    • The plasma fraction contains mainly globular proteins collectively termed livetin
    • Granular fractionis mainly composed of lipoproteins which have a fiar amount of phosphorous associated with it- termed phosvitin
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    • Gluten is uniwue- being capable of providing loaf volume, a property whihc makes bread and other wheat based leavened products to palatable
    • Gluten is made up of glutenin and gliadin
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    • Gluten is made up of glutenin and gliadin
    • Both contains ulfur and amino acids in the form of cysteine and cystine
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    • Glutenin is a glutelin- protein soluble in dilute alkali or acid- consits of a hterogeneous group of proteins which are cross inked by intermolecular disulphide bonds
    • If this fraction is isolated and hydrated, it forms a very tough elastic mass, somewhat like chewing gum
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    • gliadfin is a hydrophobic prolamine (requires alcohol for solubilization)
    • Consits of a heterogeneous group of proteins which are not cross linked, but contain extensive intramolecular disulfide bonds and free SH groups
    • If isolated and hydrated gliadin will form a very viscous solution
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    When glutenin and gliadin are mixed together, a viscoelastic mass (dough) is formed
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    A wide varity of other plant seeds have high protein contents, typically legues and oilseeds
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    Soybeans are a major oilseed crop in north america with most of the protein being used as animal feed
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    • After expelling and solvent extraction and desolventization we are left with a high protein press cake
    • When ground to 100-200 mesh the product is termed soy grits
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    • Glutenin is a glutelin- protein soluble in dilute alkali or acid- consits of a hterogeneous group of proteins which are cross inked by intermolecular disulphide bonds
    • If groung to <200 mesh it is called soy flour
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    • Production of soy concentrates
    • Soy bean concentrate contains both polysaccharide and protein, but the olidosaccharides and much of th ash has been removed
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    • Soy isolate
    • A more concentrated protein isolate can also be produced using an alternative process by removing all the carbohydrate
Author
Morgan.liberatore
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142581
Card Set
Food chem 14 pics
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food chem 14 pics
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