How to use
Making homogeneous solution is the most important procedure when obtaining the maximum performance of so-called “ALGIN”, which is a general term for the group of alginic acid, alginate salts and alginate derivatives.
The negatively charged carboxyl groups in Alginates cause the straight alginate chains to repel each other and results in a stable aqueous solution. This aqueous solution has smooth long-flow properties with Newtonian behavior.
ALGIN is a water-soluble polysaccharide and gives viscous colloidal solution.
Sodium alginate has a strong affinity with water and care is required to achieve a homogeneous aqueous solution.
It’s most important to first prepare uniform aqueous solution of ALGIN before it is utilized as a thickening agent, gelling agent, etc.
Poor dispersion in water will occur if sodium alginate is added too rapidly, producing pasty, floury lumps wetted only on the outside.
The solubility of ALGIN to water and solvents is illustrated in below.
Solubility of Alginates
- Salts of alginic acid with monovalent cations (Na-salt, K-salt, NH4-salt) as well as Alginate Ester are all soluble to cold & hot water, and generate viscous aqueous solution with long-flow properties.
- Alginic acid and calcium alginate are water-insoluble.
- All the alginate salts are insoluble to fats & oils and organic solvents.
Table 1: Solubility of ALGIN to valious type of solvent
| Type of Alginate | Solubility | ||
|---|---|---|---|
| Cold & Hot water | Fats & Oils | Organic solvents | |
| Alginic Acid | Insoluble | Insoluble | Insoluble |
| Sodium Alginate | Soluble | Insoluble | Insoluble |
| Potassium Alginate | Soluble | Insoluble | Insoluble |
| Calcium Alginate | Insoluble | Insoluble | Insoluble |
| Ammonium Alginate | Soluble | Insoluble | Insoluble |
| Propylene Glycol Alginate | Soluble | Insoluble | Insoluble |
- Solubility of ALGIN changes to some extent with the properties of solution (pH, concentration of cation, etc.)
- Care is required when making a solution of low pH or a solution that contains polyvalent cation, because ALGIN is hard to be soluble in these systems.
Table 2: Solubility of ALGIN to various type of solution
| Type of Alginate | Solubility | ||
|---|---|---|---|
| in acidic system | in alkalinic system | in solution with polyvalent cations | |
| Fluit juice, Liquor, Salad dressing, etc. | Kansui, etc. | Hard water, Milk, etc. | |
| Alginic Acid | Insoluble | Soluble | Insoluble |
| Sodium Alginate | Insoluble | Soluble※1 | Insoluble |
| Potassium Alginate | Insoluble | Soluble※1 | Insoluble |
| Calcium Alginate | Insoluble | Insoluble※2 | Insoluble |
| Ammonium Alginate | Insoluble | Soluble※1 | Insoluble |
| Propylene Glycol Alginate | Soluble | Soluble※3 | Soluble |
- notice:
-
※1 It shows a tendency that the viscosity of ALGIN solution drops in the heavy alkaline system.
※2 In [Table 2] above, it is observed that ALGIN dissolves even in the alkaline system.
※3 In the neutral and alkaline system, Alginate Ester is decomposed and generates alginate salt.