Study on extraction method of agar from Gracilaria lemaneiformis
龙须菜琼胶的提取方法研究

Agar is a polysaccharide complex extracted from the agarophyte members of Rhodophyta and it is widely used in pharmaceutical,cosmetics and food industries.Several experimental methods for agar extraction from Gracilaria lemaneiformis were studied in this paper.The effects of alkali,microwave,and ultrasonic treatments on the agar yield,sulfate content and polysaccharide content were investigated.The results obtained showed that the alkali treatment could decrease the agar yield as well as the sulfate content;the agar yield and the sulfate content were negatively affected by the increase of the NaOH concentration;on the contrary,the microwave and ultrasonic treatments could increase the agar yield as well as the sulfate content;the agar yield and the sulfate content were increased with the increasing of microwave and ultrasonic treatment time.Moreover,the states of the alga before and after alkali treatment were observed in microscopical and macroscopical conditions.