Natural gelling agents derived from red algae, used to create smooth, elastic gels (iota carrageenan) or firm, brittle gels (kappa carrageenan).
Due to its composition, kappa carrageenan forms a brittle, firm gel, which is potentiated and stabilized by the presence of potassium. Many layers of kappa molecules join together forming double helices that produce this particular texture. The final product is greatly affected by salts, sugar or proteins, such as those present in milk. Interactions between positive and negative charges of the additive and solution create a network similar to the meshes of a net, which keep all of the particles in suspension, preventing their aggregation and the collapse of the structure.
Iota carrageenan has a greater affinity with calcium, although it is not necessary in order for it to congeal. Calcium, like potassium with kappa carrageenan, lodges between double helices to stabilize the gel. Iota carrageenan usually produces an elastic gel that does not degrade if it is frozen and thawed. It also forms a stronger gel in the presence of starch.
Another type of carrageenan, lambda, significantly differs from the other two. It does not gel, with or without the addition of ions, but is used to thicken dairy products. It is used less often but is sometimes combined with kappa to change the texture of certain products.
Did you know?
- Carrageenans ensure the consistency of various dairy products such as cottage cheese and ice cream, as they prevent the separation of proteins.
- They keep cocoa particles in suspension in chocolate milk.
- They improve the texture of processed products such as sauces, dairy desserts and salad dressings, as they increase the products’ viscosity.
- They trap moisture in cured meats to give them a juicy texture.