Recherche des facteurs les plus influents sur le rendement et la qualite de l’agar-agar de Gracilaria gracilis

Abstract

This study aims at searching the influent factors (with or without the alcohol 2, propanol) on agar yield and quality of the red alga Gracilaria graclis of Bizerte Lagoon. Seven factors were studied: the concentration and the action time of each of the alcohol (2-propanol), sulfuric acid (H2SO4), soda (NaOH) and finally the concentration of bleach. Results showed that the highest agar yield (36.4 % dry weight) was recorded using a concentration of 2% of 2-propanol. The highest (385 g/cm2) and lowest (35 g/cm2) gel strength were obtained using 10% and 2% of 2-propanol, respectively. Gelling temperature ranged from 21°C to 35°C. Melting temperature varied from 69°C and 95 °C. This study has depicted the positive effect of the 2-propanol on agar yield and rheological properties of agar from G. gracilis.