Dark treatment effect on the carrageenan characterization in a red alga, Chondrus crispus

Carrageenan is a type of polysaccharides found in some seaweed species called carrageenophytes and is an essential compound in various pharmaceutical, food and cosmeceutical products. Alkali treatment is an industrial extraction method of carrageenan to improve gel quality. This method, however, has disadvantages, including producing effluents and decreasing gel yield. This study is to optimize the dark treatment duration of Chondrus crispus which is known to be an eco-friendly alternative to the alkali treatment for gel quality and yield improvements of hybrid carrageenans. In the 20-day dark treatment, yield and gel strength of carrageenan were significantly higher than control. The gel strength at the 20-day dark treatment was similar to that of alkali treatment. Sulfate content decreased as the gel strength increased. These results suggest that a dark treatment can be an alternative extraction method for carrageenan in C. crispus replacing the alkali treatment. • Twenty-day dark treatment enhances yield and gel strength of κ/ι-hybrid carrageenan. • The dark treatment can be an alternative, green method for carrageenan extraction. • Sulfate content decreased as the gel strength increased.