Carrageenan is a sulphated galactose molecule extracted from specific seaweed types making it a 100 pct. natural vegetarian product. It is mainly used as a water binder and a texturizer, in food, pet food and non-food applications. The use of Carrageenan in food products can be traced back to more than a century ago in Ireland. Its use in the production of food has steadily and dramatically increased over the last 50 years.
Carrageenans, refined (407) or semi refined (E407a), are traditionally used to bind water and provide texture in a cooked food system. Traditionally, Kappa and Iota Carrageenans dissolve during heat treatment and create a thermo-reversible gel during the following cooling procedure. The dose/usage level of Carrageenan and the ratio of liquid determine the amount of liquid that can be bound and the eventual texture characteristics of the finished product.
Both refined Carargeenan (E407) and semi refiend Carrageenan (E407a) is regarded as organic ingredients and can be applied in food with bio or/and vegan status.
In many applications, Carrageenan can do much more than just bind water. It can also:
Provide a specific texture
Provide body to an application e.g. as a fat replacer
Improve flavour release
Provide freeze/thaw stability
Carrageenan is extracted from the red seaweed class known as Rhodophyceae. It is regarded as a texturizing ingredient and may be usedinquantum satis (the amount which is needed) in many food products worldwide.
Refined and semi refined Carrageenan are approved as Carrageenan according to FDA (Regulations 21 CFR 172.620, 172.626) and the Food Chemicals Codex standards
In Europe refined Carrageenan is approved as E407 and semi refined Carrageenan is approved as E407a according to EU regulation 2012/231/EU, the Code of Federal Regulations and the Food Chemicals Codex standards
As described earlier, Carrageenan is an extract from red seaweeds. The species of seaweed is one of the determining factors of the type and functionality of the Carrageenan.
Eucheuma Cottonii, is a farmed warm water seaweed type, usually used for the production of Kappa type Carrageenans. Kappa Carrageenan provides a firm and rigid gel.
Eucheuma Spinosum, is a farmed warm water seaweed type, typically used in the production of Iota type Carrageenans. Iota Carrageenan creates a soft and elastic gel.
Chondrus Crispus and Gigartina Skottsbergii species broad leaf and narrow leaf, are examples of wild growing, cold water seaweeds typically used in the production of Lambda. Lambda Carrageenan usually contains a compound fraction of Kappa, Iota and Lambda sequences on the same molecule. The portion of each sequence varies by seaweed type, seaweed age and process. The texture of a Lambda Carrageenan ranges from a relatively firm gel to a highly viscous solution.
Furcellaria, is a wild growing cold water seaweed used in the production of Furcelleran. Furcelleran provides a semi strong and rigid gel.
The warm water seaweeds are sown and harvested on farms with stable water temperatures and tide water which carries nutrients to the seaweed. Cold water seaweed is harvested from a boat or gathered on the beaches after being washed ashore. The age of the seaweed is a significant factor when the performance of the end product is evaluated. Both cold and warm water seaweed types are dried either by the sun or by hot air and transported to production sites.
The production of Carrageenan can be split up in to two main processes:
- Refined process
Semi refined process
In the process to obtain refined Carrageenan, the dried seaweed is washed and modified by using hot temperature and an alkaline solution. The Carrageenan is melted out of the cellulose from the seaweed. This solution is filtered in order to get rid of the insoluble cellulose (also referred to as Fibre and/or Acid Insoluble Matter [ AIM ] ) and other impurities. The cellulose + minerals from the process + filter aids are typically used for field fertilization in the local areas. The hot Carrageenan slurry contains a great quantity of water. The water is usually removed by e.g.:
- Centrifugal and evaporating process. The Carrageenan slurry has the water pulled away via a centrifugal process; the remaining water is evaporated by hot air. The dry material from here is milled into Carrageenan powder.
Addition of KCl. When KCl is added, the hot solution gels and creates syneresis. The gel is pressed into semi dry “material”. This material is dried by hot air and milled into Carrageenan powder.
Precipitation. Alchohol is added to the Carrageenan slurry. The Carrageenan molecules precipitate in long fibres. These fibres are filtered away, dried by hot air and milled into Carrageenan powder.
Every process has its own unique benefits and properties, since some processes allow an ion exchange and some processes can only be applied with specific seaweed types.
For the semi refined process the dried seaweed is washed and modified by using medium high temperature and alkali. During the process the Carrageenan is alkali treated inside the cellulose matrix in the seaweed. After this process the water and processing aids are filtered away from the semi refined Carrageenan. The semi refined Carrageenan is dried by hot air and milled into semi refined Carrageenan powder.
For both processes, refined and semi refined, the level of alkali treatment can be controlled and modified. Extra washing, ion-exchange and bleaching processes may also be added to the main processes mentioned above.
As mentioned above, Carrageenan is a sulphated galactose chain with various numbers of sulphate groups, going from a low to high amount in falling order.
A Carrageenan chain consists of sequences of two galactose hexo rings linked together by Beta 1->4 and Alfa 1 ->3 linkages. Before the alkali treatment, the sulphate groups are placed on the C2 and the C4 of the alpha ring and C2, C6, on the Beta ring, depending on seaweed type.
During the alkali process, oxygen bridges are created between the C3 and C6 on the beta ring, at least on the Kappa and Iota Carrageenan. The sulphate group placed on C6 is sacrificed during this process. At the same time the beta ring will change orientation, making it possible for the Carrageenan molecule to form double helixes during cooling. The degree of alkali modification can be modified in order to gain the desired texture and solubility. There are two very important rules of thumb:
The higher amount of sulphate groups, the better the solubility, meaning lower dissolving temperature, but also weaker gel texture.
The lower amount of sulphate groups, the worse the solubility, meaning higher dissolving temperature, but also a stronger gel texture.
Gelling salt + synergistic gums
Carrageenan cannot achieve its maximum functionality without gelling ions, in practice known as gelling salts. Some gelling salts are more efficient than others, e.g. KCl is very efficient to boost the gel strength of a Kappa Carrageenan and CaCl2 boost the gel strength of an Iota Carrageenan. Below are the preferred gelling ions, in falling order, for the four types of Carrageenan:
Furcelleran: K+, Ca++, Mg++, Na+
Kappa Carrageenan: K+, Ca++, Mg++, Na+
Iota Carrageenan: Ca++, K+, Mg++, Na+
Lambda Carrageenan: Ca++, K+, Mg++, Na+ or K+, Ca++, Mg++, Na+, depending on the contribution of either Iota fraction or Kappa fraction in the product.
When Carrageenan is combined with other ingredients something extra is gained. This can be explained by both a supporting effect and a synergistic effect. The differences in these effects are explained hereto:
Supporting effect: Starch, guar gum and xanthan gum do not chemically interact with the Carrageenan molecule, but they might optimize the distribution of the Carrageenan powder during cooking and cooling and in this way provide a better end result.
Synergistic effect: Is a positive or negative interaction, between two elements. Synergistic effects in termsof Carrageenan, are related to Kappa fractions and other hydrocolloids or proteins. This refers to the positive synergism or positive interaction between the oxygen bridges on the double helix of a Kappa Carrageenan, which can interact with other gums or proteins, e.g. together with a divalent salt. Typical examples of these are:
Kappa Carrageenan + Konjac gum
Kappa Carrageenan + Locust Bean Gum
Kappa Carrageenan + Casein + Ca++ (depending of isoelectric point of theprotein)
Main functionality in applications
The main functionality of Carrageenan is to bind water. Hereafter, it may have a secondary function to modify the texture of the gel according to requirements. All Carrageenans are stable and easy to use in a wide spectrum with regard to:
This makes Carrageenan suitable in most common food products or in non-food products where water must be controlled.
EUROGUM standardizes its Carrageenans in order to ensure and secure consistent product performance. Carrageenan is a natural product and it is our expertise that allows us to consistently deliver on an established specification without variance. The performance of our products in your processes and in your finished products, remains the same from batch to batch.
The performance of a Carrageenan product depends on, but is not limited to:
Type of seaweed
Age of seaweed
Degree of alkali modification
Mesh size of the powder
Additional gelling salts
Additional synergistic/supporting gums
All these factors are important to consider when a new product is developed which may come about as a result of matching an existing product, but also as a new product starting from scratch. EUROGUM specializes in producing customized blends for all applications, with short delivery times, in order to satisfy the requirements of all our customers.