Studies On The Preparation And Modification Technology Of Gracilaria Agarose

Agarose is a value-added product of agar.Agarose is now produced using the Gelidium agar.Thus far,the Gracilaria agar hasn't been commercially processed to agarose and its derivatives due to lack of practical technology.This paper aimed to establish the process for preparing Gracilaria agarose and its derivatives,and to determine the quality characteristics.The main results are as follows:(1)Studies on the extraction of Gracilaria agarose using PEG method:Using gel strength as index,the improved process resulted from orthogonal experiment is:Solid to liquid ratio of 1:20,extraction temperature of 80? and PEG concentration of 40%.The improved process resulted in agarose extraction rate of 33%,and showing sulfate content,gel strength,transparency,solidification temperature,melting temperature,crystal violet electrophoresis distance and polyethylene glycol electrophoresis distance of 0.33%,1575 g·cm-2,63.4%,39?,87?,3.4 cm and 0.6 cm,respectively.All these quality indexes are consistent with those of standard agarose.(2)Studies on the extraction of Gracilaria agarose using EDTA-Na2 method:Using gel strength and sulfate content as indexes,the improved process resulted from single factor experiment and orthogonal experiment is:Reaction temperature of 80?,reaction time of 4 h and EDTA-Na2 concentration of 6.5 g/L.The improved process resulted in agarose extraction rate of 76%,showing sulfate content and gel strength of 0.31%and 2295 g·cm-2,respectively.Other technical indexes such as solidification temperature,melting temperature,transparency,crystal violet electrophoresis distance and polyethylene glycol electrophoresis distance have little difference with those of standard agarose.(3)Studies on the preparation process of hydroxyethyl agarose in water:Using gel strength and melting point as indexes,the improved process resulted from single factor experiment and orthogonal experiment is:NaOH concentration of 8%,ethylene oxide volume of 3 ml,reaction temperature of 70? and reaction time of 10 min.The improved process resulted in hydroxyethyl agarose yield of 84%,and showing gel strength,melting point,melting temperature of 506 g·cm-2,83?,70?,respectively.(4)Studies on the preparation process of hydroxyethyl agarose in organic solvent:Using gel strength and melting point as indexes,the improved process resulted from single factor experiment and orthogonal experiment is:Isopropyl alcohol concentration of 100%,NaOH concentration of 5%,ethylene oxide volume of 7 ml.The improved process resulted in hydroxyethyl agarose yield of 86.4%,and showing gel strength,melting point,melting temperature of 205 g·cm-2,75?,63.2?,respectively.(5)Studies on the preparation process of carboxymethyl agarose:Agarose was dissolved in water for carboxymethylation reaction.Using gel strength and melting point as indexes,the improved process resulted from single factor experiment and orthogonal experiment is:Chloroacetic acid to agarose the mass ratio of 1:1,NaOH concentration of 20%,reaction.temperature of 80? and reaction time of 60 min.The improved process resulted in carboxymethyl agarose yield of 85%.Carboxymethyl agarose quality indexes such as gel strength,solidification temperature,melting temperature,melting point and transparency are consistent with those of Sigma low gelling temperature agarose.This paper established the processes for preparing Gracilaria agarose and its derivative products,which results in high-quality Gracilaria agarose and derivative products,and provides technical references for industrial production and applications of Gracilaria agarose.