Agar Extraction from Marine Algae: Influence of Pre-extraction Treatments on Yield and Quality

CROCE, M.E.; PARODI, E.R.; VILLAR, M.

Porto de Galhinas

Congreso; XIV SLAP XII CIP; 2014

Agar properties depend on the species from which it is extracted; therefore pre-extraction treatments have been developed to increase its quality. In this study, polymers obtained from  Polysiphonia morrowii were evaluated, in order to determine the influence of pre-extraction treatments on their yield and composition. Algae were treated with alkali, acids, and acetone. Polymers characterization was carried out through Infrared Spectroscopy and Thermogravimetry. Higher extraction yields were obtained with untreated samples and with 5 % NaOH treated samples. Spectra revealed the presence of 3,6-anhidrogalactose in all samples. Highest sulfate substitution was observed in samples treated with 5 % NaOH. Polymer degradation started at a higher temperature in samples treated with NaOH 2.5 % and 10 %, similarly to commercial food-grade agar. The results of this study revealed that agar extracted from P. morrowii was highly sulfated and pre-extractions treatments did not increase the sulfate content, except for NaOH 5 % treatment.