Carrageenans, depending on the type, produce a wide range of gelling and thickening effects. Kappa and iota carrageenans will form thermally-reversible gels with potassium and calcium salts, respectively. Proteins, such as milk, soy and others will also affect the gel structure. Kappa and iota carrageenans are not cold soluble and require heat to completely hydrate. Kappa carrageenans are synergistic with a variety of other gums such as locust bean and tara and combinations of these gums form stronger gels with less syneresis. Kappa-2 carrageenans are predominantly used for milk gelling and thickening and require heat for complete solubility. Lambda carrageenans are soluble in cold water and are generally non-gellin.