1 June 2023

Sodium alginate is a natural anionic polysaccharide that is extracted from algae marine. Its chemical structure gives it interesting properties in terms of gel formation, the ability to interact with divalent cations, and participation in the stabilization of emulsions and suspensions.

It has been used in biomedical applications, such as in the manufacture of cell culture matrices and in the manufacture of wound dressings. These properties make sodium alginate a very versatile and interesting material in various industrial and scientific areas.

Concept and definition of sodium alginate

Sodium alginate is a natural anionic polysaccharide that is extracted from seaweed. Is a salt of sodalginic acid io and is characterized by having a complex chemical structure based on the repetition of units of mannuronic acid and gluronic acid.

Sodium alginate has interesting properties in terms of gel formation, ability to interact with divalent cations, stabilization of emulsions and suspensions. Due to these properties, sodium alginate has numerous applications in green biotechnologypharmaceutical, cosmetic and biomedical.

It is widely used as thickener, stabilizer, gelling agent and matrix in biomedical applications. Furthermore, sodium alginate has been shown to be biocompatible and biodegradable, making it a promising material for use in controlled drug release therapies and tissue regeneration.

Sodium alginate is known by what other name?

Sodium alginate is known also as sodium alginate E401 (your food additive number). It is important to note that although the name may vary slightly, it is referring to the same chemical compound.

Sodium alginate can also be found with the denomination ‘algin’, an abbreviated form of the name that is used mainly in the biomedical industry, where this compound is used as a matrix for tissue engineering. In general, the exact name used to refer to sodium alginate can vary by specific application in which it is being used.

What is sodium alginate used for?

sodium alginate has various applications due to its unique properties. Below are some of the main applications of sodium alginate:

  • Industry: Sodium alginate is widely used in the food industry due to its ability to form gels and improve texture of food. In the manufacture of food products, sodium alginate is used as a thickener to give foods a thicker consistency and to improve the stability and viscosity of emulsions and suspensions. For example, it can be used to produce jelly fruit, give consistency to sauces and emulsions, and improve the texture of products such as ice creams and desserts.
  • Industry pharmaceutical: In the pharmaceutical industry it is used as a thickening agent in the formulation of medicines. It is also used as a vehicle for the controlled drug release, since it can form gels that release the drug slowly over time. Additionally, sodium alginate is used in the manufacture of bandages and wound dressings due to its ability to form a hydrophilic gel that helps maintain a moist surface and promotes wound healing.
  • Industry cosmetics: Sodium alginate is used in the manufacture of cosmetic products as a thickening and gelling agent that improves the texture and consistency of products. For example, used in creams, lotions and products for hair care to provide a smoother texture and improve the ability of products to spread on the skin or hair.
  • Engineering of fabrics: In tissue engineering, sodium alginate is used as a matrix for the scaffolding construction for tissue regeneration. Sodium alginate can be molded into different shapes and sizes to create scaffolds that serve as supports for cells that are used for tissue regeneration. In addition, sodium alginate is used as a material to encapsulate cells and protect them from the body’s immune response during cell transplantation.

What is the function of sodium alginate in molecular cooking?

Sodium alginate is one of the key ingredients used in the technique of molecular cooking, known as ‘spherification’. This technique is used to create small spheres that contain liquid within, allowing for the creation of unique culinary dishes and presentations.

The main function of sodium alginate in spherification is to act as a gelling agent in the presence of calcium. It is used in combination with a liquid that contains the desired ingredient to create the sphere, such as fruit juice, sauces, or broths. The liquid is mixed with the sodium alginate to create a viscous solution that is allowed to settle for a few minutes to allow air bubbles to escape.

Then, a calcium chloride solution is prepared, which is used as a bath to submerge the liquid and sodium alginate spheres. The solution reacts with the sodium alginate to form a gelatinous layer on the surface of the spheres, which creates a solid structure on the outside and keeps the liquid inside.

The function of sodium alginate in spherification is therefore to allow the creation of spheres with a unique texture They can hold a wide variety of liquids. In addition, the spherification technique also allows you to play with flavors and colors of the ingredients, which makes it popular in creative and experimental gastronomy.

What are the characteristics of sodium alginate?

sodium alginate is a naturally occurring polysaccharide It is mainly extracted from brown algae. Here are some of its most important features:

  • Solubility: Sodium alginate is soluble in hot waterbut insoluble in organic solvents.
  • gelation: Sodium alginate has the ability to form gels in the presence of calcium ions. The speed and amount of gel formed depend on the ion concentration calcium and sodium alginate concentration.
  • Goo: Sodium alginate is a viscous polymer that increases the viscosity of the solutions in which it is found. Therefore, it is used as a thickener in a variety of applications.
  • Stability thermal: Sodium alginate is stable at temperatures moderate, which makes it suitable for use in food and pharmaceuticals.
  • Low toxicity: Sodium alginate is considered a safe food additive and is used widely in the food industry. Furthermore, it has been shown to have low toxicity in safety studies.
  • Biocompatibility: Sodium alginate has been used in medical applications due to its biocompatibility. That is, it does not cause an immune response in the human body and is suitable for use in medical products such as bandages and wound dressings.

In general, sodium alginate is a versatile polysaccharide with a wide variety of properties. industrial and medical applications. Your ability to form gels and improve viscosity makes it useful as a thickener and gelling agent, while its low toxicity and biocompatibility make it suitable for use in food and medical products.

Where is sodium alginate found?

Sodium alginate is a polysaccharide that occurs naturally in brown algaelike the species laminaria and Ascophyllum. These algae are found in marine environments, such as off the coasts of Asia, Europe, North and South America.

Sodium alginate is extracted from the cell wall of brown algae. The seaweed is washed and dried to remove surface water and then ground into a paste. Subsequently, one is made extraction with an alkaline solution, to separate the sodium alginate from other components of the cell. Sodium alginate is purified and dried for use in various industrial and food applications.

In addition to its natural origin in brown algae, sodium alginate can also be synthesized from cellulose by chemical processes. However, most uses of sodium alginate in the food and medical industry are derived from its natural extraction of brown algae.

What is the formula of sodium alginate?

The chemical formula of sodium alginate is NaC6H7O6. The chemical structure of sodium alginate is a linear polymer composed of repeating units of D-mannuronic acid and L-gluronic acid, connected by glycosidic bonds.

These polymers contain carboxyl groups that can ionize in aqueous solutions to form sodium ions, resulting in the formation of a gel in the presence of calcium ions. The chemical formula of sodium alginate can vary depending on source and the degree of purification of the polymer.

What are the advantages and disadvantages of using sodium alginate?

Sodium alginate has several advantages and disadvantages in use, which are presented below:


  • It is a natural productl: Sodium alginate is mainly extracted from Brown algae and it is a natural product that breaks down easily in the environment.
  • It’s versatile: Sodium alginate has a wide variety of applications, including the food, pharmaceutical, cosmetic, and 3D printing industries.
  • controllable gelation: sodium alginate can form gels in the presence of ions of calcium, which allows to control the speed and the amount of gel formed.
  • thickener: Sodium alginate is widely used as a thickener in food and cosmetic products due to its ability to increase the viscosity of solutions.
  • low toxicity: Sodium alginate has been shown to be a food additive sure and has low toxicity in safety studies.


  • pH sensitivity: sodium alginate is sensitive to pH and can break down in acid or alkaline solutions.
  • Cost: The cost of sodium alginate can be high compared to other thickeners and gelling agents.
  • requires calcium ions: for the gelling of sodium alginate it is necessary to add calcium ions, which may limit its use in some products.
  • low heat resistance: sodium alginate has a low resistance to heat, which you can limit its use in products that require high temperatures.

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