ALGINIC ACID

Alginic acid is a natural polysaccharide hydrocolloid, widely used as a thickening, gelling, and stabilizing agent in food, pharmaceutical, and industrial applications.
Alginic acid is derived from brown seaweeds (Phaeophyceae), such as Laminaria and Macrocystis.
Alginic acid belongs to the class of marine biopolymers.

CAS Number: 9005-32-7
Molecular Formula: (C6H8O6)n
EINECS Number: 232-680-1

Synonyms: D-Galacturonic acid sodium salt, Alginic acid sodium salt, Alginic acid sodium salt from brown algae, Sodium alginate, sodium (2S,3R,4S,5R)-3,4,5,6-tetrahydroxyoxane-2-carboxylate, Sodium D-galactopyranuronate, D-Galacturonic acid sodium salt (≥95%), D-Galacturonic acid sodium salt (≥98%), DB-266742, ALGINIC ACID;kelacid;landalgine;norgine;polymannuronicacid;sazzio;Nopgine;ALGINIC ACID FREE ACID FROM MACROCYSTIS PYRIFERA (K

Alginic acid consists of linear copolymers of β-D-mannuronic acid (M) and α-L-guluronic acid (G) units.
These units are arranged in blocks along the chain.
This structure determines its gelling properties.

Alginic acid appears as a white to yellowish fibrous powder.
Alginic acid is insoluble in water but can swell and form viscous dispersions.
Its salts (alginates) are water-soluble.

Alginic acid exhibits strong thickening and gel-forming ability, especially in the presence of multivalent cations like calcium (Ca²⁺).
Alginic acid forms stable gels through ionic crosslinking.
This is known as the “egg-box” model.

Alginic acid shows high water-binding capacity, allowing it to retain large amounts of water.
This improves texture and stability.
Alginic acid is important in many formulations.

Alginic acid is chemically stable under normal conditions, but may degrade under strong acid, high temperature, or microbial activity.
Proper storage ensures quality.
Alginic acid should be kept dry.

Alginic acid is widely used in food products, pharmaceuticals, textiles, and biotechnology.
It provides structure and stabilization.
This highlights its versatility.

Alginic acid is best described as a marine-derived polysaccharide with strong thickening, water-binding, and ion-induced gelling properties, widely used across food, medical, and industrial applications.
Alginic acid found in the walls of brown seaweeds (Phaeophyceae) consists of D-mannuronic acid units and L-guluronic acid units probably linked β (1->4). 
The chains contain three distinct regions; in one, the D-mannuronic acid units alternate with L-guluronic acid units, whereas the remaining regions are homogeneous and contain either D-mannuronic acid or L-guluronic acid. 

The lengths and proportions of the three regions vary with the seaweed species and are responsible for the differences in chemical and physical properties of the various alginates.
Alginic acid is biosynthesised from GDP-D-mannuronic acid and GDP-guluronic acid. 
Alginic acid seems probable that guluronic acid is derived from its isomer, mannuronic acid, the re action being catalysed by an epimerase.

Alginic acid is used in a variety of oral and topical pharmaceutical formulations. 
In tablet and capsule formulations, alginic acid is used as both a binder and disintegrating agent at concentrations of 1–5% w/w. 
Alginic acid is widely used as a thickening and suspending agent in a variety of pastes, creams, and gels; and as a stabilizing agent for oil-in-water emulsions.

Alginic acid has been used to improve the stability of levosimendan.
Alginic acid is a natural, hydrophilic polysaccharide extracted from brown seaweed (Phaeophyceae), widely used as a thickener, gelling agent, and stabilizer in the food, pharmaceutical, and textile industries. 

Alginic acid forms viscous gels, serving as a key ingredient in antacids to manage acid reflux, and in medical applications for wound dressings and drug delivery. 
Alginic acid is generally considered safe but can inhibit nutrient absorption if consumed in high amounts. 

Melting point: 300 °C
storage temp.: Room Temperature
solubility: H2O: insoluble, but swells
form: Powder
color: White to pale yellow to beige
Odor: wh. to yel. fibrous powd., odorless, tasteless
optical activity: -141～-146
Water Solubility: Insoluble in water
Sensitive: Hygroscopic
Merck: 14,242
Major Application: diagnostic assay manufacturing; hematology; histology
Cosmetics Ingredients Functions: VISCOSITY CONTROLLING; BINDING; SKIN CONDITIONING

Alginic acid is a hydrophilic colloid carbohydrate that occurs naturally in the cell walls and intercellular spaces of various species of brown seaweed (Phaeophyceae). 
The seaweed occurs widely throughout the world and is harvested, crushed, and treated with dilute alkali to extract the alginic acid.

Alginic acid exhibits a block copolymer structure, with regions rich in mannuronic (M) and guluronic (G) acids.
The ratio and sequence of these blocks affect gel strength.
This determines functional properties.

Alginic acid forms gels through ionic crosslinking with divalent cations, especially calcium ions (Ca²⁺).
Guluronic acid blocks bind calcium strongly.
This creates a stable three-dimensional network.

Alginic acid shows high viscosity in aqueous dispersions, even at relatively low concentrations.
Alginic acid thickens systems effectively.
This improves texture control.

The material has excellent water absorption and retention capacity.
Alginic acid can swell significantly in the presence of water.
This enhances moisture management.

Alginic acid is pH-sensitive, being insoluble in acidic conditions but forming soluble salts (alginates) at higher pH.
This allows controlled solubility.
Alginic acid is useful in formulation design.

Alginic acid exhibits biocompatibility and biodegradability, making it suitable for biomedical applications.
It is generally non-toxic.
This supports medical use.

Alginic acid can be processed into films, fibers, and beads.
These forms are used for encapsulation and delivery systems.
This increases application versatility.

Alginic acid demonstrates good compatibility with other polymers and additives.
It can be blended to modify properties.
Alginic acid is a versatile, ion-responsive hydrocolloid with strong thickening, gelling, and water-retention properties, making it valuable in food, pharmaceutical, and biomedical applications.

Uses Of Alginic acid:
Alginic acid is used in cosmetic formulations as a thickener, stabilizer, and gelling agent. 
Alginic acid is obtained from different varieties of brown seaweed.

Alginic acid which is obtained from brown seaweed genera, such as Macrocystis pyrifera. 
The derivatives are sodium, ammonium, and potassium ates of which the sodium salt is most common. 
They are used to provide thickening, gelling, and binding. A derivative designed for improved acid and calcium stability is propylene glycol ate. 

The s are soluble in cold water and form nonthermoreversible gels in reaction with calcium ions and under acidic conditions. 
Alginic acid is used in ice cream, icings, puddings, dessert gels, and fabricated fruit.

Alginic Acid is the acidic, insoluble form of algin that is a white to yellowish fibrous powder obtained from brown seaweed genera, such as macrocystis pyrifera.
The derivatives are soluble and include sodium, potassium, and ammonium alginate and propylene glycol alginate. 
Alginic acid is used as a tablet disintegrant and as an antacid ingredient.

Alginic acid is widely used in the food industry as a thickening and stabilizing agent (E400).
Alginic acid improves texture and consistency in products such as sauces and dressings.
This enhances product quality.

In restructured foods and gels, it is used with calcium salts to form firm, heat-stable gels.
It helps create shaped or molded products.
This supports food processing.

Alginic acid is applied in ice cream and frozen desserts to control ice crystal formation and improve mouthfeel.
It stabilizes the matrix.
This enhances sensory quality.

Alginic acid is used in bakery fillings and toppings to maintain viscosity and prevent separation.
Alginic acid ensures uniform consistency.
This improves shelf stability.

In pharmaceutical formulations, it is used as a binder, disintegrant, and controlled-release agent.
Alginic acid helps regulate drug delivery.
This supports therapeutic effectiveness.

Alginic acid is widely used in antacid formulations, where alginates form a protective gel barrier in the stomach.
It helps reduce acid reflux.
This improves patient comfort.

In wound dressings, alginic acid (as calcium alginate) is used for its high absorbency and gel-forming properties.
Alginic acid maintains a moist healing environment.
This supports wound care.

Alginic acid is applied in encapsulation and drug delivery systems, forming beads or gels for controlled release.
It protects active ingredients.
This enhances stability.

In textile printing, it is used as a thickener for dyes.
Alginic acid helps control dye application.
Alginic acid is used wherever thickening, ion-induced gelling, water retention, and controlled delivery are required across food, pharmaceutical, biomedical, and industrial applications.

Alginic acid is widely used in food products and topical and oral pharmaceutical formulations. 
Alginic acid is generally regarded as a nontoxic and nonirritant material, although excessive oral consumption may be harmful. 
Inhalation of alginate dust may be an irritant and has been associated with industrially related asthma in workers involved in alginate production. 

However, it appears that the cases of asthma were linked to exposure to unprocessed seaweed dust rather than pure alginate dust. 
An acceptable daily intake of alginic acid and its ammonium, calcium, potassium, and sodium salts was not set by the WHO because the quantities used, and the background levels in food, did not represent a hazard to health.

Safety Profile Of Alginic acid:
Moderately toxic by intraperitoneal route. 
When heated to decomposition it emits acrid smoke and irritating fumes

Alginic acid presents very low hazard potential, as it is a natural polysaccharide derived from seaweed and widely used in food and medical applications.
Alginic acid is generally recognized as safe (GRAS).
However, standard handling precautions are recommended.

Skin contact is typically low risk, but prolonged exposure to powder may cause mild dryness or irritation in sensitive individuals.
No significant toxicity is expected.
Protective gloves are recommended in industrial handling.

Eye contact may cause mild mechanical irritation.
Symptoms include redness and discomfort due to particulate matter.
Eyes should be rinsed thoroughly with water if exposure occurs.

Inhalation of dust may cause minor respiratory irritation.
Fine particles can irritate the nose and throat.
Adequate ventilation and dust control are recommended.

Alginic acid ingestion is considered safe at normal dietary levels, as it is used as a food additive and dietary fiber.
Excessive intake may cause mild gastrointestinal effects such as bloating or laxative action.