Effect of Storage on Quality Characteristics of Commercial Gracilaria Agars

Abstract

The yield and the physical, chemical and rheological properties of agars extracted from six commercial Gracilaria from different localities around the world, and one species of Gracilariopsis lemaneiformis, collected from a Japanese locality, were investigated after an extended storage at different treatment conditions. Agar was extracted by pretreatment with 5% NaOH incubated for 2 h at 80°C. Changes in the agar quality occurred at variable rates and were dependent on species and its origin. The Japanese Gracilariopsis species and Chilean Gracilaria chilensis were more resistant to degradation than the other agarophytes during the storage period. The agar extracts of Chilean G. chilensis showed an increase in its gel strength with tendence to be harder and less flexible, while those of Japanese Gracilariopsis were not affected even neither by storage nor by the different temperature conditions. The agar characteristics of the commercial agarophytes examined were not significantly affected by the different temperature conditions, except for Argentinean and Turkish G. gracilis.