Quality control of carrageenan extract begins at the harvest. FMC BioPolymer sources its raw materials from independent seaweed harvesters worldwide and FMC BioPolymer-operated cultivation sites. The seaweed is systematically gathered, quickly dried and then baled to maintain its quality.
At the manufacturing site the dried seaweed is mechanically ground and sieved to eliminate impurities such as sand and salt.
Following extensive washing to ensure additional quality, the seaweed undergoes a hot extraction process to separate the carrageenan from the extraneous plant fiber.
Removal of the cellulosic material requires a two step clarification process. First, we centrifuge the dissolved carrageenan mixture to eliminate the dense cellulosic particles. Then, filtration is used to remove the smaller particles.
The solution is then concentrated by evaporation to accommodate the removal of water.
The carrageenan is then recovered by one of two processing methods. In one method, the concentrated carrageenan solution is deposited into a solution of potassium chloride. This raises the gelling temperature so that the filtrate will gel immediately. The gel is then frozen and compressed while thawing to remove excess water.
In the second method, the concentrated carrageenan solution is precipitated in isopropyl alcohol. As carrageenan is insoluble in alcohol, the filtrate turns into a coagulum of carrageenan, alcohol and water. The coagulum is compressed to remove the liquids and vacuum dried to completely remove the alcohol. Drying is completed on a belt drier and the dried coagulum is then ground to specification.
Finally, the carrageenan is blended to meet the finished product’s exact specifications.