Gums or Hydrocolloids

These natural homo- and copolymers (such as starch and cellulose) are composed of sugar residues and/or their derivatives. The names carbohydrate polymer and polysaccharide refer to the chemical structure. Carbohydrate polymers are also designated as gum or hydrocolloid, which refers to the property that these polysaccharides hydrate in hot or cold water to form viscous solutions or dispersions at low concentration. The gums/hydrocolloids may be harvested from nature or obtained by the chemical modification of native polysaccharides. 

Among the additives, the most common are the gums or hydrocolloids. These products have a structure that makes them especially suitable to retain water and increase the viscosity of the masses, in fact are often referred to as thickeners. Their inclusion in the masses improves gas retention and makes less sticky mass. In some articles of bakery, products are called hydrocolloids gluten substitutes. Tara gum finds application in pastry and bakery, imparting smoothness and shape to the dough and makes cutting easier. 

The hydrocolloids used stabilize this type of icing by their ability to form a gel or a highly viscous solution. Agar-agar, locust bean gum, sodium alginate (combined with a buffer and calcium salt), Irish moss extract, pectin, and karaya gum are hydrocolloids used. The finished icing may contain from 0.1 to 0.5% hydrocolloids. 

W e know of many examples of the effect of impurities of crystallization. In many cases impurities will completely inhibit (2-4) nucleus formation. Reading the literature on this subject impresses one with the frequent occurrence of hydrocolloids as crystal modifiers, particularly where sugar or water is the material being crystallized. The use of gelatin, locust bean gum, or sodium alginate in ice cream is just one example of many practical applications of hydrocolloids in crystal modification. 

Other hydrocolloid dressings with formulations consisting of sodium carboxymethylcellulose combined with karaya gum or sodium carboxymethylcellulose on its own are also available. 

Cairns R, Morris V. J., Miles M. J., Brownsey G. J. 1986. Comparative studies of the mechanical properties of mixed gels formed by kappa carrageenan and tara gum or carob gum. Food Hydrocolloids. 1(1), 89-93. 

Polysaccharides are sometimes referred to as polyglycans or hydrocolloids . Most cosmetically interesting polysaccharides are primarily composed of six-membered cyclic structures known as pyranose ring (five carbon atoms and one oxygen atom). Many polysaccharides form helices, which is a tertiary spatial configuration, arranged to minimize the total energy of the polysaccharide (e.g. xanthan gum). 

Carbohydrate-based replacements rely on a viscosity increase and smooth gel-like textures to simulate the properties of fats and oils. These substitutes include gums, hydrophilic hydrocolloids that increase product viscosity and improve emulsion stability polydextrose, a polymer of dextrose with small amounts of sorbitol and citric acid made by Pfizer Chemical Division, New York and a variety of com, tapioca and potato starch maltodextrins made by various starch processors. Neither the protein- nor the carbohydrate-based replacements can be used as frying or dry coating oils. 

Many hydrocolloids may fulfill one or several of the requirements of a fully balanced ice cream stabilizer and still present production problems. For this reason most stabilizers are blends of several hydrocolloids provided for the specific type of frozen confection being manufactured. Soft-served ice cream and ice milk present other production and distribution problems and require substantially different blends of gums. Many studies and comments have been made on the types and levels of hydrocolloids used for stabilizing ice cream, ice milk, and mellorine (5, 6, 8, 15, 16, 2Ir 27). 

Gellan gum with various acyl contents in the presence or absence of potassium. Food Hydrocolloids 22,1148-1159. 

In addition to the necessary protection of the contents of the emulsion droplets, effective encapsulation technology requires that the release of the active matter be controlled at a specified rate. Benichou et aL (2004) have demonstrated that a mixture of whey protein isolate (WPI) and xanthan gum can be successfully used for the controlled release of vitamin Bi entrapped within the inner aqueous phase of a multiple emulsion. The release profile, as a function of the pH of the external aqueous phase, is plotted in Figure 7.25. We can observe that the external interface appears more effectively sealed against release of the entrapped vitamin at pH = 2 than at pH = 4 or 7. It was reported that an increase in the protein-to-potysaccharide ratio reduced the release rate at pH = 3.5 (Benichou et aL, 2004). More broadly, the authors suggest that compatible blends of biopolymers (hydrocolloids and proteins) should be considered excellent amphiphilic candidates to serve as release controllers and stability7 enhancers in future formulations of double emulsions. So perhaps mixed compatible biopolymers wall at last allow researchers to... 

Milk fat and milk solids-not-fat (MSNF) are most commonly obtained from cream and condensed skim milk, but may also be obtained from a combination of fluid milk, condensed whole milk, frozen cream, frozen condensed milk, nonfat dry milk, dry whole milk, and butter. Sweeteners used in the mix normally include a combination of liquid or dry sucrose, corn sweetener, high-fructose corn sweetener, and corn syrup solids. Ice cream stabilizers are formulated to contain one or more polysaccharide hydrocolloids, e.g., carboxymethyl cellulose, locust bean gum, carageenin, alginate, and other gums. Ice cream emulsifiers normally contain monoglycerides and diglycerides of palmitic and stearic... 

In addition to their role in primary stabilization related to viscosity increase, some hydrocolloids (particularly carrageenan) are traditionally used as secondary stabilizers. Many of the primary stabilizing hydrocolloids, including locust bean gum and carboxy methyl cellulose induce precipitation of the milk proteins in the mix. This phenomenon in ice cream mix is known as wheying-off, and may be due to direct protein-polysaccharide binding and/or protein-polysaccharide incompatibility in the water phase40. The latter phenomenon may be due to decreased solvent quality due to the competition between protein and polysaccharide for solubilisation. 

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