Hydrocolloid stabilizers

Starch is also of interest because it is reported to increase the viscosity of caseinate solutions in a synergistic manner, especially at caseinate concentrations 10% (Platt, 1988). The increase in viscosity was thought not to be due to any chemical interaction (Jones and Wilson, 1976) but rather to the increase in the swelling volume of the starch (Lelievre and Husbands, 1989). 

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Hydrocolloid stabilizers are vitally important in the manufacture of sherbet and ices. The absence of larger amounts of milk colloids and the presence of larger amounts of water emphasize the need for proper stabilization. Stabilizers help to maintain a Arm body and smooth texture during manufacture, storage, and distribution. Bleeding and surface sugar crystallization are two problems related to crystal structure in sherbet and ices and are very closely associated with the use of the proper hydrocolloid stabilizer. 

UHT whipping cream is intermediate between a standard whipping cream and a nondairy whipped topping. In addition to cream, the product will also contain emulsifiers and hydrocolloid stabilizers. Homogenization, which is deleterious to standard whipping cream, is essential to UHT whipping cream. 

The key factors that influence the selection of the hydrocolloid thickener for this type of application are its stability in relation to the product formulation and process and the stability and rheology of the final product. Dressings for example are usually manufactured with a cold make-up process. They often have high levels of salt and acid, which influence the hydration and stability of the hydrocolloid. Stability in the final product in terms of oil emulsions and suspension of herbs and spices is critical. The flow properties are also important and the pseudoplastic behaviour of hydrocolloids is ideal. This provides suspension and stability due to high viscosity at low shear rates but the product remains pourable at higher shear rates. Sauces are usually prepared with a hot process and consideration of the heat stability of the hydrocolloid is important. 

Qv, X. Y., Zeng, Z. P. Jiang, J. G. (2011). Preparation of lutein microencapsulation by complex coacervation method and its physicochemical properties and stability. Food Hydrocolloids, Vol. 25, 6, (August 2011), pp. (1596-1603), ISSN 0268-005X... 

Hubbermann, E.M. et al., Influence of acids, salt, sugars and hydrocolloids on the colour stability of anthocyanin rich black currant and elderberry concentrates, Eur. Food Res. Technol, 223, 83, 2006. 

Emulsifiers assist the stabilizing hydrocolloids in controlling crystal structure. They accentuate the function of the homogenizer in reducing the size of the fat globules. They also reduce the interfacial tension between the fat and water phases of the mix. The result is smaller ice particles and air cells when the mix is frozen and a smoother and creamier finished product. 

Hydrocolloids for ice cream stabilization must fill the following requirements in addition to providing heat shock protection during temperature fluctuations 16). 

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). 

In most plants, ice pop mixes are prepared cold and the hydrocolloid should be readily dispersible and soluble in cold mix. The hydrocolloid must be compatible with acid. Karaya gum (0.4%), locust bean gum (0.25%), and pectin (0.2%) were originally the stabilizers used. More recently CMC (0.25%),... 

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. 

In the production of aerated confections it is very important to add various hydrocolloids, in order to obtain a foam which will withstand the specific stability requirements of the specialty food product involved. 

The structure and the formation of foams are discussed from a theoretical point of view. The conditions for foam stability are stressed and a novel hypothesis is presented on the action of hydrocolloids as plasticizers of the walls of foams. 

A study was made of the comparative stabilities at various exposures of an upset stomach remedy suspension. This product consisted of a dispersion of bismuth subsalicylate and phenylsalicylate in an aqueous system. Methyl-cellulose and magnesium aluminum silicate were selected as the suspending agents, because the presence of polyvalent metallic ions precluded the use of hydrocolloids affected by these ions. In addition, it was found that methyl-cellulose contributed a demulcent effect. The viscosity, as well as the suspension characteristics of the combination of protective colloids used, was of a synergistic nature. These colloids formed a thixotropic system. The thixotropy undoubtedly aids in stabilizing this system. In order to make this product palatable and impart elegance, color and flavor were added. Sample 1 (with protective colloids) showed no separation, while sample 2 (without... 

Figure 6. Effect of magnesium aluminum silicate and cellu-losic hydrocolloids on stability of suspensions...

Because stabilization in the Verwey and Hamaker picture is electrical, the use of electrical methods for predicting the stability of a dispersion appears to be mandatory. Other than the work of Voet described above, little has been done in this direction. Beyond doubt, the important developments in the area of dispersion stability that will come forth will be based either on electrokinetics (for high dielectric media, especially hydrocolloids) or electrostatics. 

Spagnuolo, P. A., Dalgleish, D. G., Goff, H. D., and Morris, E. R. (2005). Kappa-carrageenan interactions in systems containing casein micelles and polysaccharide stabilizers. Food Hydrocolloids 19,371-377. 

Qian, C. and McClements, D.J. (2011) Formation of nanoemulsions stabilized by model food-grade emulsifiers using high-pressure homogenization factors affecting particle size. Food Hydrocolloids, 25 (5), 1000-1008. 

Lee, S.J. and McClements, D.J. (2010) Fabrication of protein-stabilized nanoemulsions using a combined homogenization and amphiphilic solvent dissolution/evaporation approach. Food Hydrocolloids, 24, 560-569. 

Littoz F and Mcclements DJ. 2008. Bio-mimetic approach to improving emulsion stability Cross-linking adsorbed beet pectin layers using laccase. Food Hydrocolloids 22(7) 1203-1211. 

In bakery products the pH of the product is important for several reasons. Acid foods are normally relatively safe microbiologically as a low pH inhibits the growth of bacteria. Fruit flavoured products such as fruit pie fillings normally have some acid component added to complement the fruit flavour. Where a hydrocolloid is present the pH of the product can be critical in terms of product stability or gelling. A hydrocolloid held at its isoelectric point, i.e. the pH at which there is no net charge, will likely come out of solution. 

E. Davies, E. Dickinson, and R. Bee Shear Stability of Sodium Caseinate Emulsions Containing Monoglyceride and Triglyceride Crystals. Food Hydrocolloids 14, 145 (2000). 

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