Difference Between Agar and Carrageenan

The key difference between agar and carrageenan is that agar is extracted from Gelidium and Gracilaria while carrageenan is extracted from Chondrus crispus.

Agar and carrageenan are two natural hydrocolloids obtained from seaweed, mainly from red algal species. Since both have gelling property, they are used in many different types of food preparations. Agar is best known as a solidifying component of bacteriological media. Gelidium and Gracilaria are the two red algae used to extract agar while carrageenan is commonly extracted from the red seaweed Chondrus crispus. Agar is a natural gelatinous substance used in icing, glazes, processed cheese, jelly and sweets. Agar is often used in microbiology and biotechnology applications as well. Carrageenan is a polysaccharide used in desserts, ice cream, sauces, pates, beer, processed meat and soy milk.

1. Overview and Key Difference
2. What is Agar
3. What is Carrageenan
4. Similarities Between Agar and Carrageenan
5. Side by Side Comparison – Agar vs Carrageenan in Tabular Form
6. Summary

What is Agar?

Agar is a natural hydrocolloid, which is a gelatinous substance. Agar is extracted from two genera of red algae (seaweeds) as Gelidium and Gracilaria. First seaweeds are cleaned and washed thoroughly in order to remove any foreign materials such as sand, salts, or any debris. Then the seaweeds are heated in water for several hours until agar dissolves in the water. This mixture is then filtered to remove residual seaweeds. The filtrate is cooled to form a gel which contains agar. Then the gel is broken and washed to remove soluble salts. Finally, we remove the water removed and mill the agar to a uniform particle size.

Figure 01: Agar

Agar dissolves in boiling water. It forms a gel between 32 and 43 °C. This gel does not melt until it is heated to 85 °C or higher. More than 90% of agar production is used for food applications – for icing, glazes, processed cheese, jelly and sweets, etc. Rest is used in microbiological and other biotechnology applications.

What is Carrageenan?

Carrageenan is another natural hydrocolloid, extracted from the red algae species Chondrus crispus. It is a polysaccharide. There are two types of carrageenan as refined carrageenan (RC) and semirefined carrageenan (SRC). Semirefined carrageenan contains cellulose, which is present in the original seaweed, while refined carrageenan does not contain cellulose. Cellulose has been removed by filtration.

Figure 02: Chondrus crispus

Similar to agar, carrageenan has gelling property. It also has an emulsifying property. Hence, carrageenan is used as a food additive instead of both gelatin and agar. In processed foods, carrageenan is used for stabilization, thickening and gelation. Carrageenan is also used in preparing ice cream, chocolate milk, custards, cheeses, jellies, confectionery products, meat and for clarification of beer and wine. Carrageenan is often present in nut milk, meat products, and yoghurt.

What are the Similarities Between Agar and Carrageenan?

Agar and carrageenan are two hydrocolloids.
They are composed of polysaccharides.
They are extracted from red algae species.
Seaweeds are washed to remove sand, salts and other foreign matter during the extraction process.
Both have gelling property.
They are used in food preparations.
Both are industrially extracted and commercialized.
Agar and carrageenan have no nutritional value.

What is the Difference Between Agar and Carrageenan?

Agar is a natural hydrocolloid extracted from seaweed while carrageenan is a natural hydrocolloid used as a food additive in the food industry for their gelling, thickening, and stabilizing properties. Gelidium and Gracilaria are the two red algae used to extract agar while Chondrus crispus is the red algae used to extract carrageenan. So, this is the key difference between agar and carrageenan.

Below is a summary of the difference between agar and carrageenan.

Summary – Agar vs Carrageenan

Agar and carrageenan are two natural hydrocolloids which are extracted from red algae. They have no nutritional value. Both have a gelling property, and they are used in many different types of food preparations. Agar is extracted from Gelidium and Gracilaria while carrageenan is extracted from Chondrus crispus. Thus, this is the key difference between agar and carrageenan.

Reference:

1. “Carrageenan”. En.Wikipedia.Org, 2020, Available here.
2. “Agar | Description, Uses, & Properties”. Encyclopedia Britannica, 2020, Available here.

Image Courtesy:

1. “Agar-agar” By Unkky – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Chondrus crispus Helgoland” By Gabriele Kothe-Heinrich – Own work (CC BY-SA 3.0) via Commons Wikimedia