@article{oai:kochi.repo.nii.ac.jp:00002097,
 author = {Istini, Sri and Ohno, Masao and Kusunose, Hirozo},
 journal = {Bulletin of marine sciences and fisheries, Kochi University},
 month = {Dec},
 note = {application/pdf, The extraction of agar and carrageenan was carried out after alkali treatment, and alginate after acid treatment, of samples agarophytes and carrageenophytes were treated at high temperatures whilst the alginophytes were extracted at room temperature. Agar yield and gel strength were obtained after alkali treatment (5% NaOH, at 70 and 80℃, for 2 hours) from commercially harvested Gracilaria chorda (mature and young material) from Japan; G. fisheri (cultivated and wild material from Thailand); G. verrucosa from the Philippines and G. lemaneiformis from Chile. Agar with a high yield (18.34% of dry weight) and gel strength (692±24 g.cm^<-2>) was obtained from G. chorda (mature thalli) after alkali treatment at 80℃, whilst a low yield (9.92%) and gel strength (355±22 g.cm^<-2>) was obtained from G. verrucosa.The yield and gel strength of carrageenan were obtained with alkali treatment (6% KOH), for kappa carrageenan and 6% NaOH for iota carrageenan, at 80℃ for a period of 3 hours, using different extract recovery methods (e.g. freeze-thawing, gel pressing and alcohol precipitation). The largest carrageenan yield (35.47%) of kappa carrageenan was obtained by the freeze-thawing method. Alcohol precipitation provided the best extraction of iota carrageenan (34.05%). High gel strength reading were obtained from the freeze-thawing method to extract kappa carrageenan (814±82 g.cm^<-2>) and iota carrageenan (191±5 g.cm^<-2>).The yield of alginate (1 - 2% sodium carbonate treatment) unbleached and bleached was, 32.16 and 30.65% respectively for Laminaria japonica, 33.95 and 33.72% respectively for Ecklonia cava and 27.63 and 28.68% respectively for Sargassum duplicatum.},
 pages = {49--55},
 title = {Methods of analysis for agar, carrageenan and alginate in seaweed},
 volume = {14},
 year = {1994}
}