Hydrocolloids foamed

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. 

Rouimi, S., Schorsch, C., Valentini, C., Vaslin, S. (2005). Foam stability and interfacial properties of milk protein-surfactant systems. Food Hydrocolloids, 19, 467 178. 

Sanchez, C.C., Rodriguez Patino, J.M. (2005). Interfacial, foaming and emulsifying characteristics of sodium caseinate as influenced by protein concentration in solution. Food Hydrocolloids, 19, 407 116. 

The main factor determining the stability of such foams is the rate and extent of drainage from the thin liquid film. In general, this type of foam is relatively unstable. The stability may be enhanced by increasing the viscosity of the liquid by increasing the dry matter content or adding certain hydrocolloids. The foam stability may also be enhanced with hydrocolloids, in particular microcrystalline cellulose. 

In whippable emulsions with a high fat content, the air-water interface of the foam after whipping is dominated by adsorbed deproteinated fat globules. In whippable emulsions with a low fat content other foam stabilizing mechanisms come into play, such as protein-hydrocolloid and protein-emulsifier interactions. The former subject may be studied by... 

Increased emulsifier and hydrocolloid content is necessary to obtain stable foams when the fat content is reduced. Figure 19 shows results from practical tests of ice cream systems47. 

If hydrocolloids are used in sufficient quantities to enable them to gel the mix, then they will also be able to form a stable foam when whipped. Starch and emulsifiers can also be used to provide aerated desserts with more body and a creamier consistency2. 

F. A. Husband, D. B. Sarney, M. J. Barnard, and P. J. Wilde, Comparison of foaming and interfacial properties of pure sucrose monolaurates, dilaurate and commercial preparations, Food Hydrocolloids, 12 (1998) 237-244. 

In general, they consist of a pressure sensitive adhesive layer which is composed of a so-called hydrocolloid dispersed with the aid of a tackifier in an elastomer and secondly a film coating composed of a gas permeable but water impermeable, flexible, elastomeric material. A currently available hydrocolloid dressing is a flexible mass with an adherent inner face and an outer semipermeable polyurethane foam. 

Substances that are used in wound dressings include hydrogels, hydrocolloids, alginates, and polyurethane foams. Medicaments that they contain include wool wax alcohols (amerchol, cetearyl alcohol, propylene glycol), plant resins/ethereal oils (balsam of Peru, colophony, fragrance mix, propolis), and topical antibiotics. 

Waniska, R.D. and KinseUa, J.E. 1988. Foaming and emulsifying properties of glycosylated P-lactoglobulin. Food Hydrocolloids 2 439 449. 

To a foamed gelling hydrocolloid system a firming agent and a fibrous material are advantageously added. When articles prepared from such compositions are coated with a suitable coating, they are impervious to boiling water and able to withstand microwave heating (33). 

Foegeding, E. A. Luck, P. J. Davis, J. P. Factors determining the physical properties of protein foams. Food Hydrocolloids, 2006, 20,284-292. 

Xin Yang, E. Allen Foegeding. Effects ofsucrose on egg white protein and whey protein isolate foams Factors determining properties of wet and dry foams (cakes) Food Hydrocolloids, 2010,24,227-238. 

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