While ice cream does not actually contain seaweed, many mass-produced food products, ice cream often contains a gum ingredient. One of these, carrageenan, comes from seaweed. Food gums are naturally occurring non-digestible carbohydrates that are used as stabilizers, thickeners, and binders. Guar gum is a common example of such an ingredient that is often found in ice cream. Other examples are carob bean, xanthan, cellulose, and tara gums. Carrageenan is another food gum that is often used in processed dairy products. It’s added to ice cream to help bind water and stabilize the texture. It helps to give a creamier mouthfeel and keeps those pesky ice crystals from forming. This gum additive is often found in chocolate milk, as well. While carrageenan comes from seaweed, this doesn’t mean that ice cream contains seaweed.
Carrageenan, a galactose polysaccharide, is extracted from red seaweed by soaking the cleaned and ground seaweed in an alkali solution such as potassium hydroxide (a type of lye). This caustic solution dissolves the Carrageenan present in the seaweed which can then be filtered out and purified. Other components from the plant, like cellulose, are removed. The result can then be concentrated and dried. There are different forms of carrageenan classified by the amount of sulfate they contain. Three major types are kappa-carrageenan, lambda-carrageenan, and iota-carrageenan.
The main type of carrageenan used in ice cream is kappa-carrageenan. Since it is able to form a gel with milk proteins it is added in small amounts to ice cream mixes to reduce the phase separation of milk proteins and polysaccharides, a problem known as “wheying off.” When ice cream is frozen, ice crystals, air bubbles, and fat are suspended in a “matrix.” This matrix is basically a solution of sugar in which the other components of ice cream are dispersed. However, milk proteins and stabilizers (other gums) do not tend to remain uniformly mixed. Instead, they separate into different regions of the matrix. Kappa-carrageenan forms a weak gel that helps to keep these like molecules from coalescing together, maintaining dispersion in the matrix.
Carrageenan is produced where seaweed is found, namely coastal regions of Chile, the Philippines, Canada, France, Spain, Denmark, Ireland, and the United States. Among these, Chile and the Phillipines are the chief producers. It was originally extracted from Chondrus crispis or Irish Moss but can also be derived from Gigartina skottsbergii, Gigartina rudula, and other Gigartina species; Eucheuma cottoni and Eucheuma species; Furcellaria species, and Sarcothalia chrispita. 1Clarke, Chris. The Science of Ice Cream. United Kingdom, Royal Society of Chemistry, 2004.,{note]Marshall, Robert T., et al. Ice Cream. Germany, Kluwer Academic/Plenum Publishers, 2003.[/note]
