Some kinds of red algae (seaweed) belonging to the Rodophyceae family are used to make carrageenans, which are linear sulfated polysaccharides.

Three types of carrageenan that we usually use: κ-Carrageenan (kappa), ι-Carrageenan (iota), λ-Carrageenan (lambda).

As it can complex or interact with proteins, carrageenan is frequently used to thicken, gel, or stabilize dairy-based solutions. Carrageenan is not a surfactant, but it can stabilize emulsions that are already in place.

1. When Kappa Carrageenan reacts with calcium or potassium salts, it gels. Kappa Carrageenan creates brittle, stiff gels when calcium is present. Nevertheless, Kappa Carrageenan produces extremely rigid and elastic gels in the presence of potassium salts.

2. Lambda carrageenan is a thickening agent but does not gel.

3. To create a heat-reversible, flexible soft gel, iota carrageenan, a superb thickening and gelling ingredient, is frequently combined with fruits and dairy products. Iota Carrageenan is vegetarian and a great substitute for gelatin because it needs calcium ions to form a gel. Iota carrageenan gels into a soft substance, especially when calcium is present.

Concentration Range: Iota carrageenan gels at 1%-1.5% concentrations and thickens at 0.02%-1% concentrations. Kappa Carrageenan thickens between 0.02% and 1.5% and gels at concentrations above 1.5%. Use 0.2% Iota and 0.15% Kappa to produce eggless custard or flan. Use 0.25% Iota and 0.25% Kappa for a cold terrine. 0.2% Kappa and 0.4% locust bean gum should be combined to create a stiff and brittle jelly. Combine 0.45% Iota and 0.35% Kappa to create a thick gel that will coat meals. Use 0.1% of Iota to thicken a cold dairy sauce. Use 0.2% of Kappa and 0.35% Iota to create a pudding-like, thicker cold fluid. Keep in mind that outcomes will differ depending on whether you use calcium or potassium, and that these concentrations are only for reference.

Setting: Once the carrageenan solution has been disseminated, it must be heated to around 79°C (175°F) to be completely hydrated. At temperatures below 45°C (113°F), the solution begins to gel. The gel will become stronger as the calcium or potassium content increases, allowing gels to set at higher temperatures and lower concentrations.

If an Iota Carrageenan preparation is stirred, a gel will not form; nevertheless, if the mixture is let to rest, the gel will reform.