Production of carrageenan from seaweed (Eucheuma cottoni) with KOH treatment

Eucheuma Cottoni is one type of seaweed that is widely used. This seaweed contains carrageenan in the range of 61.5-67.5 % on a dry weight basis. Carrageenan is a hydrocolloid compound that consists of ester potassium, sodium, magnesium and potassium sulphate with copolymer 3.6-anhydrogalactose. This research is aimed to study the effect of the concentration of alkaline solution (KOH), temperature, time and the concentration of salt solution (KCl) on the yield and gel strength of carrageenan generated in the extraction process. The best process conditions such as the concentration of KOH, temperature and time were found to obtain the best quality of carrageenan in terms of gel strength quality. The research procedure consisted of the preparation of raw materials, KOH treatment, and the extraction process with water. In the KOH treatment, process consists of several variables i.e. the KOH concentration in range of 4-10%, treatment temperature from 60 to 90 °C, and treatment time from 60 to 150 minutes. In the extraction process, KCl concentrations in the range of 0.2-0.5 N were used. Carrageenan yield is calculated and analyzed in terms gel strength. The results indicate that the increase of KOH concentration and treatment time caused an increase of yield and gel strength. The same result also indicate that the increase of treatment temperature caused the increase of yield. Meanwhile based on the gel strength test, the temperature in KOH treatment of 80 °C resulted in the higher value. The KCl concentration does not affect the yield and gel strength but affects the speed of penjendalan. In KOH treatment, the best process conditions to produce the best gel strength quality are 10% KOH aqueous solution, the treatment temperature of 80 °C, and the treatment time of 150 minutes.