超声辅助乙醇提取核桃青皮总黄酮及纯化工艺

Ultrasound-assisted ethanol extraction and purification of flavonoids from walnut peel

核桃是重要的林业经济树种。随着核桃产量逐年上升,核桃青皮常被当作废弃资源,将核桃青皮变废为宝备受关注。本研究探究了核桃青皮总黄酮的最佳提取及纯化工艺,对比了不同提取溶剂及提取方法对总黄酮提取率的影响,通过Box-Behnken试验优化提取条件,对提取所得核桃青皮总黄酮样品进行纯化,分别分析了上样质量浓度、上样流速、乙醇体积分数和洗脱流速对总黄酮纯化效果的影响。实验结果表明:核桃青皮总黄酮的最佳提取方法为超声辅助乙醇提取法;最佳提取条件为乙醇体积分数50.52%,超声温度80.19℃,超声时间47.01 min,核桃青皮总黄酮提取率达52.45%。为符合实际工艺操作,以乙醇体积分数51%、超声温度80℃、超声时间47 min对最佳提取工艺进行验证,得出核桃青皮总黄酮提取率为52.53%,与模型预测结果基本吻合(P<0.05)。采用AB-8大孔树脂对总黄酮纯化的效果最佳,且在上样质量浓度4 mg/mL、上样流速3 BV/h、乙醇体积分数70%、洗脱流速2 BV/h的条件下,总黄酮纯化效果最佳,样品回收率为84.45%,总黄酮纯度为81.10%。本研究可为核桃青皮总黄酮的提取纯化提供科学依据和技术支持,为核桃青皮的资源再利用提供新思路。

Walnut is a traditional economic tree species in China.With the continuous increase of walnut production,the accumulation of walnut peel has gradually increased.Most of the walnut peel is discarded as agricultural waste,which not only causes a great waste of resources,but also causes pollution to the environment.Therefore,it has received much attention for turning walnut peel into treasure.The effects of different extraction solvents and different extraction methods on the extraction rate of flavonoids were compared to explore the optimal extraction and purification process of flavonoids from walnut peel.The extraction conditions were optimized using Box-Behnken experimental design,and the effects of loading mass concentration,loading flow rate,ethanol volume fraction and elution flow rate on the purification efficiency were explored.The results showed that the optimal flavonoids extraction method was ultrasonic-assisted ethanol extraction.The results of single factor experiment showed that the extraction rate of flavonoids from walnut peel was the highest when ethanol volume fraction was 50%,ultrasonic time was 45 min and ultrasonic temperature was 80 ℃.The optimal extraction conditions were ethanol volume fraction of 50.52%,ultrasonic temperature of 80.19 ℃ and ultrasonic time of 47.01 min.In this condition,the extraction rate of flavonoids was 52.45%.For the convenience of practical operation,the optimal extraction process was verified by ethanol volume fraction of 51%,ultrasonic temperature of 80 ℃ and ultrasonic time of 47 min,and the extraction rate of flavonoids from walnut peel was 52.53%,which was basically consistent with the software design results.Among the results of D3520,D101,HPD-600,AB-8 and DM130 macroporous resins on the adsorption and desorption rates of flavonoids from walnut peel,AB-8 macroporous resin exhibited the best purification efficiency on flavonoids.The results of dynamic adsorption experiment show that the best purification conditions of flavonoids were loading mass concentration of 4 mg/mL,loading flow rate of 3 BV/h,ethanol volume fraction of 70%,and elution flow rate of 2 BV/h.The purity of flavonoids after purification was 81.10%.This study was aimed at providing scientific basis and technical support for the extraction and purification of total flavonoids from walnut peel,solving the problem of resource waste and environmental pollution caused by the increase of walnut production year by year,and providing new ideas for the reuse of walnut peel in agriculture,food,medicine and other fields.