The Role of Stabilizers
The ice cream stabilizers, locust bean gum, guar gum, carboxymethyl cellulose, sodium alginate, carrageenan, and xanthan, are a group of ingredients used commonly in ice cream formulations. They are usually integrated with the emulsifiers in proprietary blends. The primary purposes of using stabilizers in ice cream are to produce smoothness in body and texture, retard or reduce ice and lactose crystal growth during storage, and to provide uniformity of product and resistance to melting. Additionally, they stabilize the mix to prevent wheying off, produce a stable foam with easy cut-off at the barrel freezer and slow down moisture migration from the product to the package or the air. The action of the polysaccharides in ice cream result from their ability to form gel-like structures in water and to hold free water. Control of iciness by stabilizers has been attributed to a reduction in the growth of ice crystals over time, probably related to a reduction in water mobility as water is entrapped by their entangled network structures in the serum phase. Proper formulation with stabilizers designed to combat against heat shock is an almost essential defense against the inevitable growth of ice crystals. Low total solids mixes are also more difficult to effectively stabilize as the increased content of water leads to more ice at any given temperature. Also, high concentrations of sugars or lactose will change the ratio of water to ice and lead to greater problems of recrystallization.
Stabilizer functionality in ice cream is an active area of our research here at the University of Guelph. Please see the work of one of my graduate students, Alejandra Regand, in this area, based on her M.Sc. thesis work, which focuses on the structure of polysaccharides in frozen solutions. Please also see my publications for more details of our research.