响应面优化超声波辅助[Bmim]Cl-K2HPO4双水相提取黄秋葵多糖

  目的  探讨超声波辅助[Bmim]Cl-K₂HPO₄提取黄秋葵多糖的最佳工艺。  方法  采用浊点滴定法，比较[Bmim]Cl-(NH₄)₂SO₄、[Bmim]Cl-Na₂HPO₄、[Bmim]Cl-Na₂CO₃和[Bmim]Cl-K₂HPO₄等4种双水相体系的分相能力与萃取能力，确定[Bmim]Cl-K₂HPO₄为最佳双水相体系。以黄秋葵Abelmoschus esculentus为原料，采用超声波辅助[Bmim]Cl- K₂HPO₄提取黄秋葵多糖，探讨K₂HPO₄质量分数、提取时间、提取温度、液固比、[Bmim]Cl质量分数等5个单因素对提取率的影响。在各单因素试验最佳条件的基础上，进行响应面Box-Behnken设计，优化黄秋葵多糖提取工艺。  结果  各因素对提取率影响大小依次为液固比、[Bmim]Cl质量分数、提取温度、提取时间、K₂HPO₄质量分数；最佳工艺条件为5 mL质量分数71.94%的离子液体[Bmim]Cl，5 mL质量分数22.31%的K₂HPO₄双水相体系中，提取时间29.36 min，提取温度55.69 ℃，液固比25.00 mL·g?1，黄秋葵多糖提取率为29.12%。验证平均值为31.22%，相对标准偏差为3.70%。  结论  超声波辅助[Bmim]Cl-K₂HPO₄提取工艺具有提取率高、时间短、离子液体可回收等优点，可用于工业化生产。图8表3参24

Extraction of polysaccharides of Abelmoschus esculentus using ultrasonic-assisted [Bmim] Cl-K2HPO4 aqueous two phases optimized by response surface method

  Objective  This study attempts to explore the optimum technology of ultrasonic-assisted [Bmim]Cl-K₂HPO₄ extraction of okra polysaccharides.  Method  Cloud point titration was used to compare the phase separation ability and extraction ability of four aqueous two-phase systems, [Bmim]Cl-(NH₄)₂SO₄, [Bmim]Cl-Na₂HPO₄, [Bmim]Cl-Na₂CO₃ and [Bmim]Cl-K₂HPO₄. [Bmim]Cl-K₂HPO₄ was determined to be the best aqueous two-phase system. The polysaccharides were extracted from okra (Abelmoschus esculentus) by ultrasonic-assisted [Bmim]Cl-K₂HPO₄. The effects of five single factors on the extraction rate were discussed: mass fraction of K₂HPO₄, extraction time, extraction temperature, liquid-solid ratio and mass fraction of [Bmim]Cl. On the basis of the optimum conditions of each single factor experiment, the Box-Behnken design of response surface was applied to optimize the extraction process of okra polysaccharides.  Result  The results showed that the effects of various factors on the extraction rate ranging from large to small included liquid-solid ratio, mass fraction of [Bmim]Cl, extraction temperature, extraction time, and mass fraction of K₂HPO₄. The optimum extraction conditions were aqueous two-phase system consisting of 5 mL ionic liquid [Bmim]Cl with mass fraction of 71.94%, and 5 mL K₂HPO₄ with mass fraction of 22.31%, extraction time of 29.36 min, extraction temperature of 55.69 ℃, and liquid-solid ratio of 25.00 mL·g?1. Under the above optimized extraction conditions, the predicted value of extraction rate was 29.12%. The validation average was 31.22%, and RSD was 3.70%.   Conclusion  Ultrasonic-assisted extraction of [Bmim] Cl-K₂HPO₄ has such advantages as high extraction rate, short time and recyclable ionic liquids, and can be used in industrial production. [Ch, 8 fig. 3 tab. 24 ref.]