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Published byRoland Hunt Modified over 9 years ago
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Freeze dried oven dried butanol ethanol B E Spray dried ethanol E ALPHA HELIX BETA SHEET
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0.1 mm mmmm MAINLY HELICAL MAINLY SHEET
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Heat treatment during the extraction and drying process appears to cause denaturation and aggregation of kafirin, decreasing solubility. Kafirin films, where the -helical structure of the “native” protein has been retained, are better quality, smoother and more transparent, than those containing aggregated proteins with a greater -sheet content. Denatured/aggregated kafirins give less homogeneous films showing phase separation
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α β abcdeabcde a = unmodified film, b = 5 %, c =, 10 %, d = 15 %, e = 20 % level of modification FT-IR spectra of kafirin films with sorghum condensed tannin
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Tannic acid and sorghum condensed tannins stabilised the kafirin α-helical structure and decreased β-sheet formation Tannic acid cross-linking decreased the mobility of the kafirin polypeptide chains
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PREDICTED VALUE RAW DATA CORRECTED FOR MOBILE PROTEIN WITH DEUTERATED GLYCEROL
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GLYCEROL INCREASES THE ALPHA HELICAL CONTENT OF THE PROTEIN AND CAUSES MORE MOBILE MATERIAL TO APPEAR THAN CAN BE EXPLAINED SIMPLY BY THE AMOUNT OF PLASTICISER ADDED. Glycerol must also act as solvent
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heat solvent Hydrophobic interiors unwind slightly And coagulation takes place. Degree of unwinding/ coagulation is determined by the thermal history of the sample
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dry Tannin dry
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plasticiser
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MOSTLY IMMOBILE MOBILE Reverts to random coil or alpha helix RIGID CORE Remains alpha helical Highly mobile region More plasticiser Some absorption of glycerol Glycerol acts at as a solvent for the unwound region.
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