Carrageenan is a common food additive derived from various red edible seaweeds. While cultures have used seaweed extracts for centuries, carrageenan became a commercially produced additive in the 1940s. It belongs to a family of large, flexible molecules called linear sulfated polysaccharides. This structure gives carrageenan its ability to thicken and stabilize foods, though it provides no nutritional value.
Sources and Functions in Food Production
Carrageenan is extracted from several species of red seaweed (Rhodophyta). A well-known source is Chondrus crispus, a dark red alga often called Irish moss. The manufacturing process involves harvesting the seaweed, which is then washed, boiled, filtered, and dried to produce a powder used as the food additive.
The primary function of carrageenan is to act as a gelling, thickening, and stabilizing agent. There are three main commercial types, each with distinct properties based on its degree of sulfation: kappa, iota, and lambda. Their molecular structures allow them to form different kinds of gels and textures.
Kappa-carrageenan creates firm, sometimes brittle gels and has a strong binding affinity for milk proteins, making it useful in dairy products like cottage cheese and ice cream to prevent whey separation. Iota-carrageenan forms soft, elastic gels, often used in desserts like puddings to create a smooth texture. Lambda-carrageenan does not form a gel but is an effective thickener, commonly used to improve the mouthfeel of products like chocolate milk, almond milk, and creamy soups.
The Health and Safety Debate
The health debate distinguishes between food-grade carrageenan (also known as undegraded) and a substance called poligeenan, or degraded carrageenan. Poligeenan is produced through a separate process of acid hydrolysis, which breaks down the large polysaccharide molecules. It does not have the gelling or thickening properties of its food-grade counterpart and is not permitted for use in food.
In laboratory settings, poligeenan is a known inflammatory agent used to induce inflammation in animal tissues for research. This has led to concerns that food-grade carrageenan might cause similar inflammation or be contaminated with the degraded form. Some studies suggest a link between food-grade carrageenan and gastrointestinal issues like bloating in certain individuals.
Conversely, many studies and food safety organizations maintain that food-grade carrageenan is safe. They argue its molecular weight and structure are substantially different from poligeenan, preventing it from being absorbed or causing harm. Proponents of its safety note that adverse effects in lab studies often involve high doses or poligeenan, not the amounts found in food. The conflicting research leaves the topic open to debate.
Regulatory Approval and Labeling
In the United States, the Food and Drug Administration (FDA) lists carrageenan as Generally Recognized as Safe (GRAS). This classification means the substance is considered safe for its intended use in food based on available scientific evidence. The FDA also sets specifications to limit the amount of potential degraded carrageenan to a very low level in the food-grade product.
Other international agencies concur. The European Food Safety Authority (EFSA) approved its use as food additive E407. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) also found carrageenan acceptable for use in food, without setting a numerical limit on daily intake.
For consumers who wish to identify its presence, carrageenan must be listed by name in the ingredient list on food labels. It will appear as “carrageenan,” allowing individuals to make informed choices based on their dietary preferences or health concerns.