三相萃取法纯化枸杞多糖

Purification of Lycium barbarum Polysaccharides by Three Phase Extraction

利用三相萃取法可避开多糖的醇沉过程,达到短时间内分离多糖的同时,也可一定程度的分离子水提液中的蛋白质和黄酮的原理,本文采用此法分离枸杞多糖,考察了叔丁醇-(NH_4)_2SO_4-水提液体系的三相萃取性质,研究了提取液中(NH_4)_2SO_4的添加量、叔丁醇添加量、萃取液pH、温度对枸杞提取液多糖、蛋白质、黄酮的萃取率的影响,并通过正交试验优化了多糖的萃取条件,研究发现:多糖最佳萃取条件是:10 mL提取液中(NH_4)_2SO_4添加量为30%(w/v)、叔丁醇添加量为10 mL、温度为35℃、pH为6,此时多糖的萃取率可达95.31%,蛋白质萃取率可达83.45%,黄酮萃取率可达50.66%。通过多糖的红外光谱、抗氧化活性实验可发现三相萃取法所得多糖与乙醇沉淀法所得多糖的化学结构,抗氧化活性均无太大差异。因此,该体系是一种可行的高效分离纯化枸杞多糖的绿色方法。

The three phase extraction method can avoid the alcohol precipitation process of polysaccharides to separate polysaccharides in a short time.At the same time,the protein and flavonoid in the aqueous extract of ionic water can also be segregated in a certain extent.In this paper,Lycium barbarum polysaccharides were separated by this method,and the three phase extraction properties of tertiary butanol-(NH4)2SO4-aqueous extract system were investigated.The effects of four factors,including the amount of(NH4)2SO4 in the extract,the amount of tertiary butanol,pH and temperature of the extract,on the extraction rate of polysaccharides,protein and flavonoids from Lycium barbarum extract were studied,and the extraction conditions of polysaccharides were optimized by orthogonal experiment.The optimum extraction conditions were as follows:10 mL extract(NH4)2SO4 was added to 30%(w/v),tertiary butanol was added to 10 mL,the temperature was 35℃and pH was 6,the extraction rate of polysaccharides reached 95.31%,the protein extraction rate reached 83.45%,and the extraction rate of flavonoids reached 50.66%.The infrared spectra and antioxidant activities of polysaccharides showed that there was no significant difference in the chemical structure and antioxidant activity of polysaccharides obtained by three phase extraction and ethanol precipitation.Therefore,the system would be a feasible and efficient method for separating and purifying Lycium barbarum polysaccharides.