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Arabinogalactan

Arabinogalactan is a polysaccharide which varies in molecular weight from low molecular weight polymers to large macromolecules. Arabinogalactan is a polymer of arabinose and galactose in varying ratios which are combined to form molecules with a general ball-like configuration. Arabinogalactan is also commonly referred to as larch gum, larch wood sugar, galactoarabinan, L-arabino-D-galactan, and stractan. Arabinogalactan includes naturally occurring or synthetic arabinogalactan, portions of arabinogalactan (such as degradation products), and chemically or biochemically modified arabinogalactan or portions thereof. Preferably, the arabinogalactan is a naturally occurring arabinogalactan, isolated from one or more natural sources. Arabinogalactan is obtained from several plant and tree sources including, for example, the genus Larix (also referred to as Larex) which may contain up to about 35% of arabinogalactan within the total heartwood of some species. Arabinogalactan proteins (AGPs) are found in flowering plants from every taxonomic group tested. These proteoglycans are widely distributed in most higher plants, occurring in almost all tissues including leaves, stems, roots, floral parts, seeds, and in many of their secretions. Among the hydroxyproline-rich glycoproteins isolatable from plants, AGPs are characterized by their generally low protein content and their general ability to bind the beta-glucosyl Yariv reagent. AGPs are components of gum arabic, a gummy exudate from the acacia tree, Acacia senegal, that is frequently used in food products as an emulsifier, crystallization preventer, and flavor eincapsulator. Arabinogalactan provides a useful low cost alternative to the use of fractionated dextrans in aqueous two phase extractions of biological material. Arabinogalactan from Larex species is useful since it is extremely water-soluble, occurs naturally with a very narrow molecular weight distribution. In addition, arabinogalactan can be used in the presence of enzyme systems which degrade other polysaccharides. Arabinogalactan has physical and organoleptic properties which makes it suitable for inclusion in sweetening compositions. It has no noticeable sweetness itself and thus does not itself add sweetness to the composition. Its inclusion in a sweetening composition does not increase the effective calorific value per unit sweetness of the composition, and thus compositions of the invention are suitable for incorporation into dietetic and diabetic foods.

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