Yield and quality of carrageenan from Kappaphycus alvarezii subjected to different physical and chemical treatments

Abstract

With a view to findout a suitable method for carrageenan extraction from Kappaphycus
\nalvarezii, a detailed investigation was made on quantitative and qualitative estimation of
\ncarrageenan subjected to different physical and chemical treatments. The dried material
\npresoaked in KOH and heated for 5 hours at 900C and precipitated with propanol gave the
\nmaximum yield of 59.4 % and viscosity of 25.25 cps. In Ca(OH)2 treatment, the yield was
\nalmost similar to that of KOH treatment but the viscosity was very low (9.45 cps). The gel
\nwas found to be brown in colour when treated with NaOH and milky white with Ca (OH) 2.
\nKOH gel was thick, translucent with high viscosity. Pretreatments of dried seaweed with
\nNaOH, KOH and Ca (OH) 2 followed by pressure-cooking showed relatively higher yield of
\ncarrageenan, but the viscosity, clarity and the texture of the gel were found to be poor. Clarity
\nof gel obtained by KOH- methanol treatment was higher when compared to other treatments.
\nThe yield of carrageenan was higher when the extracted material was frozen overnight and
\nthawed, but the gel was brown in colour with less rigidity. The present study shows that
\ntreatment with KOH gives better yield and quality gel.