壳聚糖絮凝竹叶提取液及机理探讨

Chitosan Flocculation on Extraction Solution of Bamboo leaves and Flocculation Mechanism Analysis

以澄清率和黄酮保留率为评价指标,考察了絮凝剂种类与用量、溶液pH值、絮凝时间与温度等因素对竹叶醇提取水溶液絮凝效果的影响。结果表明,壳聚糖絮凝效果明显优于明胶;单因素及正交实验法得到壳聚糖絮凝的较优工艺条件为:溶液pH值5.5,壳聚糖质量浓度为0.1mg/mL,40℃下絮凝10min,静置2h,此时竹叶醇提取水溶液的黄酮保留率为95.8%、澄清率为95.0%。且壳聚糖对竹叶醇提水溶液的絮凝效果优于竹叶水提液和醇提液。Zeta电位和傅里叶红外变换(FT-IR)光谱分析表明,壳聚糖通过电中和反应和吸附架桥作用除去竹叶提取液中的脂类、鞣酸类、蛋白质、多糖和小分子萜类等杂质,提高溶液的澄清度,同时对竹叶黄酮有很好的保留作用。

Clarification rate and flavonoids retention rate of Bamboo leaves extraction solution were taken as evaluation index.The influences of various flocculation parameters on the flocculation effect of Bamboo leaves ethanol aqueous solution have been studied,such as types and dosage of flocculant,pH value of solution,flocculation time and temperature.The results show that the clarification effect of chitosan is better that of gelatin.The flocculation conditions were optimized by single factor and orthogonal experiments,and the optimum process conditions are pH of 5.5,chitosan mass concentration 0.1 mg/mL,flocculating of 10 min at 40℃and clarification time of 2 h.Under these conditions,flavonoids retention rate and clarification rate were 95.8% and 95.0%,respectively.The chitosan flocculating effect on the ethanol aqueous solution of Bamboo leaves was better than that on water-extraction and ethanol-extraction solution.Zeta potential and Fourier Transform Infrared spectra results reveal that chitosan could remove lipids,tannins,proteins,polysaccharides and small molecular terpenoids in Bamboo leaves extraction solution by electrical reaction and adsorption bridging to improve the clarity,and has a good retention effect on Bamboo leaves flavonoids.