壳寡糖-水解麦醇溶肽共聚物的制备和表征

以初步纯化的微生物转谷氨酰胺酶(MTGase)催化合成壳寡糖-水解麦醇溶肽共聚物,研究最佳合成条件并对共聚物进行了表征。 结果表明,合成共聚物的最佳条件是:壳寡糖/水解麦醇溶肽质量比为1:40,在pH值6.00~6.50、50 ℃下搅拌反应50 min,共聚物的生成率达到60%~70%。 红外光谱分析显示,与壳寡糖相比,由于引入的吸电子基团产生诱导效应,共聚物酰胺-C=O基的伸展振动峰向高波数位移动且吸收强度加强。 由DTA分析可知,共聚物在60.91 ℃处失水,387.55 ℃处熔融,665.25 ℃处开始彻底分解,与壳寡糖和麦醇溶肽的差异明显。 XRD分析可知,共聚物的结晶度显著降低,晶胞数据不同于壳寡糖,表明其不易结晶。 HPLC分析表明,共聚物主要由两个组分构成,占共聚物总量的80.6%,其相对分子质量分别为66069和27285。 共聚物不溶于水及多种有机溶剂,微溶于1%NaOH,溶解度为0.184 mg/100 g。 熔程为162~163 ℃。

Preparation and Characterization of Chitosan Oligo-Saccharide-Hydrolyzed Gliadin Copolymer

The optimal conditions for the synthesis of chitosan oligosaccharide-hydrolyzed gliadin copolymer by roughly-purified microbial transglutaminase(MTGase) catalysis were investigated, and the structures of obtained copolymer were characterized. These optimal conditions are estimated as the substrates mass ratio of chitosan chitosan oligosaccharide and hydrolyzed gliadin is 1:40 under pH 6.00~6.50, and 50 min stirring at 50 ℃. The grafting rate at these conditions can reach up to 60%~70%. Infrared spectrum analysis of the copolymer shows that, compared with chitosan oligosaccharide, the introduction of electron withdrawing group to chitosan oligosaccharide-hydrolyzed gliadin copolymer has inductive effects on the amide C=O, and causes the vibration peak shift to higher wave number with enhanced absorption intensity. DTA curve indicates that the chitosan oligosaccharide-hydrolyzed gliadin copolymer begins to lose the associated water at 60.91 ℃, melt at 387.55 ℃, and completely degrade at 665.25 ℃. This is significantly different to that of chitosan oligosaccharide and gliadin. XRD analysis shows that the crystallinity of grafted copolymers is greatly reduced, the cell data is different from those of chitosan oligosaccharide. HPLC analysis shows that the copolymer has two main components, accounting together for 80.6% of the total mass. The relative molecular masses of the two main components are 66069 and 27285, respectively. The copolymer does not dissolve in water and many organic solvents, but is slightly soluble in 1% NaOH, with a solubility at 0.184 mg/100 g. The melting range of the copolymer is 162~163 ℃.