Polysaccharides Other than Starch

Meier, H., and Reid, J.S.G., Reserve polysaccharides other than starch in higher plants, in Encyclopedia of Plant Physiology, Vol. 13, Loewus, F.A. and Tanner, W., Eds., Springer-Verlag, Berlin, 1982, pp. 1418-1471. 

NSP, by definition, includes all the plant polysaccharides other than starch. For the reasons given above, NSP are divided into two broad classes in the classification and measurement scheme described here (Table 1) (1) the cell-wall NSP, which impart rigidity, and encapsulate and control the release of other nutrients, and (2) other NSP, including gums and refined preparations of cell-wall material, which occur in foods mainly as additives. There is no endogenous human enzyme for the hydrolysis of NSP, which are therefore nonglycemic, and all become available for fermentation in the large intestine. 

Cereals also contain polysaccharides other than starch. In endosperm cells their content is much less than that of starch (cf. Table 15.29). They include pentosans, cellulose, 3-glucans and glu-cofructans. These polysaccharides are primarily constituents of cell walls, and are more abundant in the outer portions than the inner portions of the kernel. Therefore, their content in flour increases as the degree of fineness increases (cf. rye as an example in Table 15.36). 

From a nutritional and physiological viewpoint, soluble and insoluble polysaccharides other than starch and lignin (cf. 18.1.2.5.1) are also called dietary fiber. The most important fiber sources are cereals and legumes, while their content in fmits and vegetables is relatively low. 

A more precise analytical method permits measurement of the specific polysaccharides other than starch (section 4.2.1.6) that are the main constituents of dietary fibre the results of such analysis are quoted as non-starch polysaccharides (nsp). 

Non-starch polysaccharides A group of polysaccharides other than starch which occur in plant foods. They are not digested by human enzymes, although they may be fermented by intestinal bacteria. They provide the major part of dietary fibre. The main non-starch polysaccharides are cellulose, hemicellulose (insoluble non-starch polysaccharides) and pectin and the plant gums and mucilages (soluble non-starch polysaccharides). 

In the third paper of the series, concerned with the formation of -(copper thiolthiocarbonyl) derivatives of polysaccharides, Lieser and Hackl reviewed the few earlier studies on polysaccharides other than cellulose. They claimed that the starch xanthates obtained by Cross, Sevan, and Briggs and by Ost and his colleagues had been given incorrect formulas,... 

In the present experiment, we measure the amount of the active ingredient, acetylsalicylic acid (see also Experiment 35), in common aspirin pills. Companies use different fillers and in different amounts, but the active ingredient, acetylsalicylic acid, must be the same in every aspirin tablet. We separate the acetylsalicylic acid from the filler based on their different solubilities. Acetylsalicylic acid is very soluble in ethanol, while neither starch, nor other polysaccharides, or even mono- and disaccharides used as a fillers, are soluble in ethanol. Some companies may use inorganic salts as fillers but these too are not soluble in ethanol. On the other hand, some specially formulated aspirin tablets may contain small amounts of ethanol-soluble substances such as stearic acid or vegetable oil. Thus the ethanol extracts of aspirin tablets may contain small amounts of substances other than acetylsalicylic acid. 

The malleable term hemicellulose in the title of this Chapter refers to all of the types of polysaccharide in the Gramineae, other than celluloses, starches, and fructans. The term implies nothing concerning the nature of the polysaccharides, their biological role, or their location in the plants. 

Matsumura [185-188] has oxidized a wide range of polysaccharides, starch, xyloses, amyloses, pectins, and the like with hypochlorite/periodate. The products are either biodegradable at low oxidation levels or functional at high oxidation levels the balance has not yet been established for commercial success. Other than Matsumura, van Bekkum and co-workers, at Delft University, has been the major player in the search to control the hypochlorite/periodate liquid-phase oxidations of starches [189-191]. He has been searching for catalytic processes to speed up the oxidation with hypochlorite. Hypobromite is a more active oxidant than hypochlorite but more expensive, however, it may be generated in situ from the cheap hypochlorite and bromide ion in one solution [191, 192]. This is shown in Scheme 16. 

Other large scale biopolymers are polysaccharides. Polysaccharides are relatively complex carbohydrates. They are polymers made up of many monosaccharides joined together by glycosidic linkages. They are therefore very large, often branched, macromolecules. Polysaccharides tend to be amorphous, insoluble in water, and have no sweet taste. When all the constituent monosaccharides are of the same type they are termed homopoly saccharides, when more than one type of monosaccharide is present they are termed heteropolysaccharides. Examples include storage polysaccharides such as starch and glycogen and structural polysaccharides such as cellulose and chitin. 

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