Thickening agents polysaccharides

Another example of a food emulsion is the ice cream, in which the colloidal dispersion of ice particles is achieved together with tiny entrapped air bubbles in an emulsion consisting of fats, sugar, and thickening agents (polysaccharides). 

Some by-products from the food industry contain high proportions of plant cell walls which can be used in human nutrition to produce "dietary fibre" or "functional fibre", i.e. compounds which can be used for their water-holding/binding properties, oil-binding capacity,... or as a source of polysaccharides such as pectins which are suitable after extraction, as gelling or thickening agents. 

Other natural polysaccharides used as thickening agents include gum arabic, gum tragacanth and xanthan gum, but these are of diminishing significance nowadays. 

The main function of the foam stabilising agent is to reinforce the intercellular film wall by contributing rheological characteristics of viscoelasticity. The increased viscosity may also assist handling. The aim, as so often with auxiliaries, is to achieve an optimum balance. If the bubbles are too thin and wet too quickly they will collapse prematurely, whilst too stable a film could hinder uniform application. Examples of products used as foam stabilisers include thickening agents such as the polysaccharides, hydroxyethylcellulose, methylcellulose,... 

The addition of hydrocolloids (e.g. carrageenans, pectins or car-boxymethyl cellulose) as thickening agents will greatly increase the apparent viscosity of the product. The production of extracellular polysaccharides by certain bacteria will also increase the viscosity of milk products. 

Starch Polysaccharide (n times Glu) Used in foods as a filler and thickening agent naturally present in many foods... 

Other polysaccharides have found widespread application Gums, which are complex, highly branched polysaccharides produced by plants, form very viscous solutions in water at low concentrations. Examples such as gum tragacanth have been used as thickening agents in foods in place of starch and to alter the texture of ice cream. 

In addition to the synthesis of polysaccharides, the transglucosylation activity of GH family 13 amylosucrase from N. polysaccharea has been employed to modify amylo-polysaccharides, underlying the interest of this enzyme for the design of novel thickening agents, resistant starches, and original carbohydrate-based dendritic nanoparticles [73, 74]. 

Polymeric thickening agents used in foods typically are well soluble polysaccharides, with an excluded volume parameter [j clearly above zero. This implies that especially the dilute and semidilute regimes are often of importance. Viscosity of very dilute solutions has been discussed in Sections 6.2.2 and 6.3.2. For higher concentrations, the reduced viscosity (j sp/c) is higher, as is true for any system (see Figure 5.5), but for polymer solutions the viscosity increases far stronger with concentration as soon as the chain overlap concentration is reached. 

Although pectins are not employed as thickening agents, pectin solutions exhibit the non-Newtonian, pseudoplastic behavior characteristic of most polysaccharides. As with solubility, the viscosity of a pectin solution is related to the molecular weight, DE, and concentration of the preparation and the pH and presence... 

Fundamental concepts of starch chemistry provide an interpretation of its function and behavior in various food uses. The characteristics of modified starches depend on granule structure and on specific size and shape of the component molecules. Most native starches contain both linear and branched polysaccharides. The linear fraction is responsible for gel formation and for various retrogradation effects, the branched fraction for high colloidal stability and good suspending qualities. Starches are employed in the food industry as gel formers, thickening agents, and colloidal emulsifiers. Desired characteristics can frequently be enhanced by choice of an appropriate modified starch. The various food uses are individually discussed from the standpoint of molecular behavior and optimal types of modification. 

Tamarind flour is used as food thickeners, stabilizers, and gelling agents. Polysaccharides from tamarind seeds can be used to replace pectin in the manufacture of jellies and jams, can be used in fruit preserving with or without acids, and can be used as a stabilizer in ice cream, mayonnaise, and cheese. 

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