Carrageenan

Brief Overview

Carrageenan is a family of natural linear sulfated polysaccharides extracted from red edible seaweeds. The most common red seaweed used for manufacturing carrageenan is Chondrus crispus, which grows along the northern part of the Atlantic. Three commercial types of carrageenan vary in functionality based on their degree of sulfation and the number of galactose molecules.

These include:
1. Iota. In the presence of calcium, iota carrageenan forms a soft gel.
2. Kappa. In the presence of calcium, kappa carrageenan forms a stiff and brittle gel, but in the presence of potassium salts, it forms firm and elastic gels.
3. Lambda. While not gel-forming, lambda carrageenan can be used as a thickener.
Of these, kappa is the most used type of carrageenan in the food and beverage industry.
All three carrageenan forms have stabilizing properties in the presence of casein and whey protein.

Manufacturing Process

There are two different methods of producing carrageenan: 

1. The carrageenan is extracted from the seaweed into an aqueous solution in the original method. The seaweed residue is removed by filtration. Then the carrageenan is recovered from the solution as a dry solid containing little other than carrageenan. This recovery process is difficult and expensive relative to the costs of the second method.

2. In the second method, the carrageenan is never actually extracted from the seaweed. Rather the principle is to wash everything out of the seaweed that will dissolve in alkali and water, leaving the carrageenan and other insoluble matter behind. This insoluble residue consists largely of carrageenan and cellulose. It is then dried and sold as semi-refined carrageenan (SRC). The process is much shorter and cheaper because the carrageenan does not need to be recovered from the solution.

Food Industry 

Carrageenan is used as a food additive because it can bind water, promote gel formation, thicken, stabilize, and improve palatability. For this reason, carrageenan is used in a wide range of processed foods, including dairy products, water-based foods, confectionary products, meat products, beverages, bakery products, desserts, soups, condiments, and infant formulas.

Cosmetic and Personal Care Industry

Cosmetic and personal care products that may contain carrageenan include toothpaste, shampoo, shaving cream, cleansing product, air freshener gel, lubricant, moisturizer, and facial cream. Carrageenan stabilizes toothpaste preparation, absorbs body fluid when formulated in wound dressing, and interacts with human carotene to give soft skin in the body and hand lotions and silky hair in shampoo.

Pharmaceutical Industry 

Carrageenan is used as a gelling agent/viscosity enhancing agent for controlled drug release and prolonged retention due to its strong negative charge and gelling. Carrageenan is also used for tissue regeneration with therapeutic biomacromolecules and for cell delivery.