| Ahnfeltia plicata is an undeveloped alga which widely distributes in the Japan,Koreanand and Russian Peninsula with an enormous biomass. Firstly, a new andecofriendly method was developed to produce agar from A. plicata, and the quality ofagar from A. plicata was compare with those of other agars produced by otheragarophytes. Secondly, the produced agar was further purified and fractionized toprepare agarose and agaropectin, and the qualities and structures of those were studied.The purpose of this study was to develop a new raw material and establish aneffective process to produce agar, agarose, and agaropectin, so as to accelerate thedevelopment of the seaweed industry in China to improve our internationalcompetitiveness.⑴Study on the preparation and characterization of agar from A. plicata. Hotwater extraction, dilute acid extraction and alkaline extraction methods werecompared for the effects of yield, and dilute alkaline extraction was indicated to be thebest method to extract agar from A. plicata. Single factor experiment was conductedto obtain the optimal extraction conditions of NaOH concentration of1.2%,solid-to-liquid ratio of1:30w/v, and autoclave time of2-hours. Single factorexperiment and response surface method experiment were carried out to establish theoptimal procedure of bleaching, and the optimal condition was chlorine concentrationof0.18%, pH value of5.39, and bleaching time of ten minutes. Finally, the quality ofagar from A. plicata was as follows. The yield was18.10±0.7%, gel strength was1030.50±74.26g/cm2, transmittance was48.1±1.2%, ash content was1.19±0.14%,sulfate content was0.55±0.08%and3,6-anhydrogalactose was33.29±1.63%. Ascompared with other traditional agarophytes, A. plicata could produce agar of superiorquality and less environment pollution.⑵Study on the purification and the quality of agarose from A. plicata. Three methods were applied to purify agarose from A. plicata agar and their qualities werecompared with those of commercial agarose. The result showed that the sulfate andash contends of agarose purified by the method of aqueous two-phase extraction（ATPE）were0.28±0.02%and0.80±0.09%, which were not satisfactory. The fuzzyelectrophoresis pattern was further indicated that the single–step method of ATPEcouldn’t be used to prepare agarose with satisfactory quality. However, the method ofATPE was fast and easy to be continuously operated, so it could be used aspretreatment method for extraction of agarose. The sulfate and ash contends ofagarose purified by the method of DEAE-Cellulose chromatography were0.15±0.02%and0.16±0.01%. The value of electroendosmosis （EEO） was0.120±0.01%and its electrophoresis pattern was clear. Its quality was as good as theagarose from BIO WEST Company and medium EEO agarose from Sigma Company.The sulfate and ash contends of agarose purified by the method of ATPE combinedwith DEAE-cellulose Chromatography were0.07±0.02%and0.11±0.07%, and thevalue of EEO was0.113±0.02%. Compared with two kinds of agarose of A. plicataabove described, its quality was the best and as good as the low EEO agarose fromSigma Company.⑶Study on the fractionalization and characterization of agaropectin from A.plicata. In order to have a comprehensive study on the fractions of agar from A.plicata, the bound substances in DEAE-Cellulose medium were eluted with0.5Mfollowed by1.0M of NaCl of300mL. The results showed that two fractions elutedwith0.5M of NaCl and1.0M of NaCl were agaropectins composed of same kinds ofmonosaccharide of D-mannose and galactose. The average molecular weights were4569.30Da and4760.30Da, respectively. The low molecular weight indicated itspotential to develop functional product of agaropectin from A. plicata. The FT-IR andUV absorbance spectrograms indicated that functional groups of two fractions weretypical and no protein and nucleic acid residues remained in the fractions. |
PDF Full Text Request