Extraction Of Active Substances In The Gracilaria

Among Gracilaria’ s bioactive ingredients, agar and phycobiliproteins are thehigher value components. The conventional processing method was adopted to extractboth of them separately, which caused a great waste. This research was to improve theextraction method, so as to achieve the purpose of the comprehensive extraction andincrease the utilization value of Gracilaria. Firstly, on the basis of the existingextraction method, these two active ingredients were extracted respectively, and thetraditional processing technology was improved at the same time. Further, theproperties of the product were explored. After that, the steam explosion technologywas brought in replacing the traditional cell disruption technology; polysaccharidesand phycobiliproteins were separated all together, and then each of them wasextracted respectively. These two results above were compared to investigate thealternative meaning of the new technology.The main results are as follows:(1) Phycobiliprotein extraction: Freeze-thaw and mechanical shear had been anapproach to fragment cells, then trichloroacetic acid was the best for crude proteinextraction, the purity of crude extraction was1.44. Sephadex G-100columnchromatography was adopted to separate and purify the protein, which could increasethe purity to3.75. The phycobiliproteins preservation environment was analyzed todetermine the optimum condition for preservation, pH7and4℃.(2) Agar extraction: The optimum technological conditions:10%NaOH solutionat70℃for2hr.5%sodium hypochlorite bleaching for1hr, extracting the gel under121℃for2hr. The final extraction rate reached29.3%and the gel strength was upto543g/cm~2. The effect of electrolyte on gel strength was considered, and the resultwas that the gel strength reached the highest degree when adding potassium chloride0.2%, which was632g/cm~2.(3) Comprehensive extraction: The experimental results were analyzed todetermine the optimal steam blasting parameters at the temperature of150℃, dwelltime15s, loading rate80%. Meanwhile, the agar alkali process was adjusted asfollows: alkali concentration reduced at2.5%, time for0.5hr. And the final gelextraction rate was32%, phycobiliproteins purity was4.06. After analysis and comparison, it was found that steam explosion technology inphycobiliproteinsz and agar extraction could increase the extraction rate, and throughthe integrated extraction, the loss of the raw materials was reduced to a low degree.With the improvement of the extraction technology, the addition of alkali and otherreagents was reduced, which decreased the environmental pollution and improved theutilization value of Gracilaria.