Effects of precipitation treatment on the extraction of carrageenan from Eucheuma spinosum

Eucheuma spinosum is one kind of seaweed that is usually cultivated in the sea as a monoculture carrageenan producer. Carrageenan is one of the important seaweed extracts. Carrageenan can be divided into kappa, iota, and lambda carrageenan. Eucheuma spinosum material is processed by extraction into iota carrageenan which is used as an ingredient for making soft capsules. The aim of this research is to compare the quality of carrageenan Eucheuma Spinosum extract harvested from the coast of Maluku. The study was conducted through two different extraction methods: aging and direct precipitation. In aging methods, samples were set for 16 hours before isopropanol precipitation, while in direct precipitation, samples were directly processed. This study used a randomized block design with three repetitions for each treatment. The properties of the final products were determined in terms of yield, viscosity profile, gel strength, and sulfate content. The physical properties were characterized using a rapid visco analyzer and texture analyzer. FTIR analysis was also used to observe the functional groups of the chemical structure between extracts. Samples run on the aging treatment showed an average value of 49.14% yield, viscosity at 83 cp, gel strength at 71.872 gf, and 12.99% of sulfate content. However, samples prepared using the direct precipitation method showed yield at 40.72%, viscosity at 20 cp, gel strength at 60.104 gf, and 13.30% of sulfate content. This study shows that the aging precipitation treatment affects the extract properties, resulting in higher values of viscosity and gel strength.