Topic overview

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Polysaccharides can be classified by composition as homopolysaccharides or heteropolysaccharides, and by function as storage, structural, or protective materials. Starch, cellulose, inulin, and dextran illustrate how different sugar units and glycosidic linkages distinguish homopolysaccharides; pectin, gums, mucilages, and glycosaminoglycans represent heteropolysaccharides. Their properties support varied roles, including energy storage, rigidity, water swelling, gel formation, and use in pharmaceutical formulations. The topic also introduces extraction by hot-water treatment and alcohol precipitation, along with diagnostic reactions such as Molisch and iodine tests. Hydrolysis can release constituent sugars for identification and quantitative assays, while quality testing includes measures such as the swelling index.