Science Fair Project Encyclopedia
Dextrins are a group of carbohydrates produced by the hydrolysis of starch. They have the same general formula as carbohydrates but are of shorter chain length. Industrial production is generally performed by acidic hydrolysis of potato starch. Dextrins are water soluble, white to slightly yellow solids which are optically active. Analytically, dextrins can be detected with iodine solution, giving a red coloration. Cyclical dextrins are known as cyclodextrins. They are formed by enzymatic degradation of starch by certain bacteria, for example Bacillus macerans. Cyclodextrins have toroidal structures formed by 6-8 glucose residues.
Dextrins find widespread use in industry, due to their non-toxicity and their low price. They are used as water soluble glues, as thickening agents in food processing, and as binding agent in pharmaceuticals. In pyrotechnics they are added to colored fire formulas, allowing them to solidify as pellets or "stars." Cyclodextrins find additional use in analytical chemistry as a matrix for the separation of hydrophobic substances, and as excipients in pharmaceutical formulations.
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