Foods, carbohydrates oligosaccharides

The nutritional value of a dietary food carbohydrate(s) depends to a large extent on the amount and type of carbohydrates that is provided to elicit a function. This underlying concept of nutrition forms the basis for all analytical methods used to determine the carbohydrate nutritive value of a food. One of the most commonly performed analyses is the determination of carbohydrates. As mentioned above, these carbohydrates include simple sugars, sugar alcohols, oligosaccharides, and polysaccharides. 

Low, N. H., Brisbane, T., Bigam, G., and Spoms, P. (1988). Carbohydrate analysis of western Canadian honeys and their nectar sources to determine the origin of honey oligosaccharides. /. Agric. Food Chem. 36, 953-957. 

Carbohydrates mainly occur in food in the form of polymers (starches and glycogen). They are cleaved by pancreatic amylase into oligosaccharides and are then hydrolyzed by glycosidases, which are located on the surface of the intestinal epithelium, to yield monosaccharides. Glucose and galactose are taken up into the enterocytes by secondary active cotransport with Na"" ions (see p. 220). In addition, monosaccharides also have passive transport systems in the intestine. 

Acetonitrile precipitation has been the subject of some papers dealing with the analysis of mono- and disaccharides in milk and dairy products, oligosaccharides in soybeans, and general methods for sugars in foods (23). Aqueous ethanol has also been frequently utilized in the extraction of lipids as undesirable components along with the carbohydrates. A further treatment with chloroform will free the hydroalcoholic extract from the lipids. 

These carbohydrates may be added to all kinds of foods, such as cereals, cakes, biscuits, and health drinks. They can be extracted from things like chicory root or produced from sugar by the action of specific enzymes. A little FOS is also to be found in bananas, leeks, and wheat, and the other prebiotics also occur naturally, but no fruit or vegetable by itself can supply the 5 g of oligosaccharides needed daily to boost the good bacteria. Indeed the normal person s diet contains only about 2 g of these carbohydrates. 

Ourane, R., Guibert, A., Brown, D., and Bomet, F., A sensitive and reproducible analytical method to measure fructo-oligosaccharides in food products, in Complex Carbohydrates Definition, Analysis and Applications, Cho, L., Prosky, L., and Dreher, M., Eds., Marcel Dekker, New York, 1997, pp. 191-201. 

Among the renewable raw materials, cellulose is among the most abundant ones. In contrast to other carbohydrates, such as saccharose or starch cellulose, processing does not compete with food production. In the context of examples of the conversion of carbohydrates, the term cellulose may also include oligosaccharides and monosaccharides, such as sucrose or glucose. This is because cellulose conversion almost always includes a depolymerization to soluble fragments, which are further converted. 

NPC has also found some apphcations in the held of carbohydrate analysis. Typical stationary phases used for this application are alkyl amine-, diol-, or polyol-bonded silicas [50-53]. Alkyl amino-bonded silicas are commonly used for the separation of saccharides and oligosaccharides in various matrixs, such as food or biological huids. Although water is used as part of mobile phase, the retention behavior of carbohydrate follows the NPC retention behavior. 

Structural studies on melanoidins are in their infancy, but it does appear that they can contain intact carbohydrate fragments, particularly if oligosaccharides are involved. Pyrolysis yields a range of compounds containing aromatic heterocycles, which contribute to the odour of cooked food, with many having furan rings. ... 

Such traditional soybean foods as tofu (soybean curd) and tempeh have little flatus activity (42). In the case of tofu, oligosaccharides are presumably eliminated during the course of its preparation, and, in the case of tempeh, enzymes produced by the mold (Rhizopus) during fermentation probably hydrolyze the oligosaccharides. As might be expected because of their low carbohydrate content (< 1%), soy protein isolates are devoid of flatus activity (43). It follows that textured meat analogs made from isolated soy protein are most likely free of flatus activity. 

Carbohydrates are ubiquitous. Every organism contains some carbohydrate. Carbohydrates can range from a simple monosaccharide to a large complex polysaccharide. Polysaccharides in combination with proteins, lipids, and nucleic acids play an important role in many plant and animal metabolic systems. Carbohydrates have many roles in food systems, where they function to provide flavor, structure, and texture to food and nutritional benefits to the consumer. This chapter attempts to address the role of common plant monosaccharides, oligosaccharides, and polysaccharides as ingredients in food systems by discussing their occurrence in plants, commercial processing, functionality, food uses, and healthful properties. 

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