Characteristic
Since alginic acid is insoluble in water, it alone does not function as a thickener or gelling agent. In order to dissolve alginic acid in water, it is necessary to neutralize by adding alkali.
Alginic acid is soluble by making a salt with monovalent cations such as Na and K. It becomes insoluble by making a salt with polyvalent cations like Ca and Fe.
Alginic acid does not dissolve in water. However, special processing can be used to make a type of alginic acid that easily absorbs water and swells.
This swelling type of alginic acid increases its apparent viscosity when it absorbs water and becomes a swelled liquid similar to starch paste.
Thus, alginic acid can be broadly divided into two types: swelling and non-swelling.
Alginic acid is known to be more susceptible to heat than sodium alginate and other alginate salts. Its molecular weight (degree of polymerization) decreases over a short period of time.
In order to maintain molecular weight, storage at the lowest temperature possible is required.
Application
Food Applications
Alginic acid is used in wheat flour products like noodles and bread to improve the product quality.
Adding alginic acid to flour dough helps water retention and gives a soft texture to products.
Alginic acid also has an effect on starch and proteins in wheat flour causing reinforcement of the dough structure after cooking or baking.
Major Applications
- Bakery
- Instant noodles
- Confectionary
- Frozen noodles
Safety
Pharmaceutical Applications
Alginic acid is insoluble in water but becomes soluble when neutralized with alkali.
Medicinal tablets can be insoluble in the stomach but soluble in the bowels. To release the active medical ingredient properly in the bowels, tablets include alginic acid, a disintegrant, which swells in water.
Powders such as starch are commonly used but if alginic acid (a tablet disintegrant) is added, this produces tablets which show different properties from starch.
These tablets have a gastro resistance function as the alginic acid does not dissolve in the stomach acid and the tablets are subsequently delivered to the intestine.
Alginic acid begins to dissolve as the surrounding pH gradually increases in the intestine, where the tablets disintegrate and the active ingredient is released.
Alginic acid is important in designing tablets which are insoluble in the stomach and soluble in the intestines.
Grades
Selection Guide (Typical Products)
Food / Pharmaceutical grade
SEAKOL ACID
| SF | FCC |
| SN | NF |
| SEB | EP, BP |