Locations

Alginates are salts of alginic acid, a polyuronide made up of a sequence of two hexuronic acid residues: 

• (beta) - D - mannuronic acid unit and
• (alpha) - L - guluronic acid

Guluronic acid block

Three types of blocks exist: 

• Homogeneous mannuronic acid (M-M-M-M )
• Homogeneous guluronic acid (G-G-G-G)
• Alternating acids (M-G-M-G)

The two sugars are not distributed at random along the chain, but sometimes form blocks of up to twenty units. The proportion of these blocks depends on the species of seaweed and whether the stipe ("stalk") or blade ("leaf") of the seaweed is used. The number and length of the blocks is very important as these factors determine the physical properties of alginates.

In solution, alginates can be used as thickening or gelling agents. These properties depend on the presence or absence of calcium ions.

Thickening

When a soluble alginate is dissolved, the acid groups are entirely ionized and a viscous solution is obtained. With high viscosity and shear-thinning properties, its rheology is typical of solutions of flexible coil macromolecules. These two properties are proportional to the concentration and the molecular weight. As the temperature rises, the viscosity decreases. This is reversible.
 

Calcium-induced gelation of alginates 

The guluronic segments of alginate chains resemble a buckled ribbon. In the presence of calcium ions, segments that are homogeneous can associate to form aggregates similar to an "eggbox". Within these junction zones the chains are in a regular pleated structure that is stabilized by calcium ions, each neutralizing a negative charge on two different chains. As a result, alginates richer in these blocks form stronger gels. When the calcium-induced crosslinks are strong and numerous, an alginate gel will be thermally irreversible.

Alginates' composition and use is regulated under food additive law in the EU, and it is GRAS in the USA. It also is included in the International Codex Alimentarius. Particular references include:

FAO/WHO - Codex Alimentarius

Alginic acid and alginates (ammonium, calcium, potassium and sodium salts) have been given an Acceptable Daily Intake (ADI) of "not specified" by the FAO/WHO Joint Expert Committee on Food Additives (JECFA).

European Union

Alginic acid (E 400) and Alginates (E 401 to E 404) are listed in Annex I of the European Parliament and Council Directive 95/2/EC of 20th February 1995 on food additives, and may be used under “quantum satis” conditions in most foods.   

United States

The FDA recognizes alginic acid and alginates as GRAS (Generally Recognized As Safe) in the Code of Federal Regulations (CFR 21).

Cargill's global team of regulatory and food law experts will be glad to provide assistance on regulatory, nutrition-related claims and food law-related issues.

The raw material used to produce alginates is brown seaweed. Sodium and potassium alginates are soluble in water and alginic acid and its calcium salt have very low water solubility.

The manufacturing process comprises four main steps: 

• Demineralization
• Extraction
• Precipitation of alginic acid
• Neutralization and obtention of alginates

Cargill started producing alginates in 1968 in Lannilis, France. The site is located close to a major seaweed site on the Brittany coast. Continuous investment in the site ensures the most up-to-date processes are in use, enabling a high level of flexibility in response to customers' requirements.

The Lannilis site (France) is FSSC 22000:2013 - ISO 9001: 2008 certified

Cargill carrageenans produced in Europe are Kosher and Halal certified. All regional, national and international certifications are issued by well-known official certification bodies and available upon request.

With over 50 years of experience, we have acquired a thorough knowledge of all relevant technologies in carrageenan manufacture and formulation. Our expertise is based on our knowledge of both the specific characteristics of carrageenans and the requirements of a broad spectrum of industries and functionality, resulting in specially tailored products optimized for different applications.

The manufacturing of carrageenan in all its varieties requires a high level of production expertise.

Cargill's worldwide sourcing of seaweed ensures the supply of a broad spectrum of properties and functionalities in its carrageenan raw materials.

The plants use the latest extraction, separation and drying technologies and are designed to produce the full range of carrageenans (refined alcohol process, refined KCl process and P.E.S.).

Each processing stage is performed under tight quality controls. The reproduction of commercial products is ensured by strict formula controls and exact monitoring conditions.

Helping your business succeed by differentiating you from your competitors is our primary goal.

In Cargill’s carrageenan business, we take time to understand your specific needs in order to provide solutions, not just products. Worldwide customers recognize this and benefit from our:

• Modern plants using the latest extraction, separation and drying technologies
• Wide range of applications from thickening to gelling properties
• Specialty and customized products
• Industry-specific solutions designed for the particular needs of the meat, dairy, confectionery, bakery and personal care industries

Helping your business succeed by differentiating you from your competitors is our primary goal.