Studies On Modification And Preparation Methods Of Low Gelling Temperature Agarose

Agarose is a polysaccharide which derived from Gracilaria, Gelidium and other red algae, and its main component is galactose polymers. Low gelling temperature agarose is agarose derivative which has a lower gelling temperature(26℃~30℃).The gelling temperature of natural agarose solution is usually 35℃~40℃.Under this temperature, many organisms and sensitive reagents will lost activation. So it is important to reduce the gelling temperature of agarose. But now low gelling temperature agarose products mainly rely on foreign imports. In this thesis, we explore the chemical modification on agarose by different modifiers, and analyze the change of gelling temperature and gel strength of modified agarose. Finally,low gelling temperature agarose derivatives have been prepared.1 This experiment explored the influence of different modifiers on agarose by evaluating the gelling temperature,gel strength and sulfate content of modified agarose. Compared the effect of different modifiers, including ethylene chlorohydrin, epichlorohydrin, 1,2,3-tribromopropane, dimethyl carbonate and iodomethane. The dimethyl carbonate, iodomethane and andethylene chlorohydrin modified agarose had a bigger change on gelling temperature and gel strength.2 Different chemical modification on agarose by modifiers including dimethyl carbonate, iodomethane and andethylene chlorohydrin. Under different reaction conditions, the modified agarose had different gelling temperature. To explore the effects of reaction system Na OH concentration, reaction temperature, reaction time and modifier dosage through a series of single factor experiment. Respectively determined the optimal reaction system of each modifier. 2g of agarose ① 2.10% Na OH concentration, 5 m L of dimethyl carbonate, reaction temperature of 85 ℃,the reaction time of 90 min. ②2.10% Na OH concentration,2 m L of methyl iodide, reaction temperature of 75℃,the reaction time of 75 min.③4.21% Na OH concentration, 3 m L of andethylene chlorohydrin, reaction temperature of 50℃,reaction time of 75 min.3 Tested the gelling temperature, gel strength, sulfate content, molecular weight, electroosmosis, whiteness of agarose modified by dimethyl carbonate, iodomethane and andethylene chlorohydrin. The structure was analyzed by using infrared spectrum. The results showed that the agarose modified by iodomethane and andethylene chlorohydrin met the quality requirments of low gelling temperature agarose. They can be used for the preparation low gelling temperature agarose.