Dispersions powdered polysaccharide

The surface of a powdered polysaccharide equilibrated in air is hydrophobic and resistant to wetting—a condition that poses difficulty in dispersal when cereal flour, for example, is mixed with water in the preparation of doughs and batters. Dispersion usually requires a large expenditure of mechanical energy. 

The addition of dispersed saccharides/polysaccharides to enhance the adherence of composite or fat coatings on a bakery product has been suggested in various patents (Anonymous 1979 Haynes et al. 2004 Heuvel et al. 1997 Youcheff et al. 1996). The effect of sugars, cocoa powder, emulsifier and fat type on the WVP (3.5%-100% RH, 20°C) of chocolate coatings was investigated by Gosh et al. (2005) and rmder-lined the favourable effect of sucrose on the WVP of the barrier. 

Tamarind kernel powder is insoluble in cold water, but upon heating forms thick viscous coUoidal dispersions at relatively low concentrations (2—3%). Upon drying, elastic films are formed. Tamarind seed polysaccharide is used as a low cost textile sizing agent in India. 

In a binary dispersion, there is usually one of five interfaces to consider, where a polysaccharide, for example, may act as a protective colloid. These interfaces are liquid-solid (sol), liquid-liquid (emulsion), solid-solid (mixed xerogel), liquid-air (foam), and solid-air (powder). In any of these systems at... 

For polysaccharide dispersions, SV is exceedingly small relative to Vi. Equations (3.11) and (3.12) are mathematical propositions that the exchangeable energy stored in a dispersed polysaccharide solute is equal to the energy absorbed from an external source and any increase in surface area of the solute is consequently a repository of +A . Conversely, aggregation and desorption correspond to a loss of energy, felt as heat in the latter occurrence ( —A ) when a dry polyaccharide powder is wetted (positive adsorption). 

Arabinogalactan occurs as a white to yellow-white, coarse or fine powder. It is the dried water extract from the wood of the larch trees Larix occidentalis and Larix laricina (Fam. Pinaceae). It is a highly branched polysaccharide that has a molecular weight of 15,000 to 60,000 daltons and is composed of galactose units and arabinose units in the approximate ratio of 6 1. It is freely dispersible in hot or cold water. It is insoluble in alcohol. 

The quality of the final encapsulated lipid powder depends on a number of factors including, the amount of Hpid encapsulated, the fraction of lipid exposed to the environment, the long-term chemical stability of the lipid, the flowability of the powder, the dispersibility of the powder, etc. These parameters can be controlled by selecting appropriate concentrations and types of components to make up the initial emulsion, as well as appropriate operating parameters for the spray dryer (e.g. flow rates, inlet, and outlet temperatures). Water soluble polymers (such as proteins and polysaccharides) are often used as emulsifiers to stabilize oil-in-water emulsions prior to spray drying, and after re-dispersion of the dried powder into liquid. Alternatively, water soluble polymers may make up part of the wall material that helps encapsulate and protect the lipid in the powder during storage. 

Pol 4ner films basing on ultra dispersed low-density polyethylene powder modified by the natural polysaccharide, chitosan have been obtained under the combined effect of high pressure and shear deformation. Their water-absorbent capacity and biodegradability are estimated... 

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