枸杞子结合多酚碱水解与酸水解提取工艺的比较和产物分析

Comparison of alkaline and acid hydrolysis extraction of non-extractablephenolic compounds in Lycii Fructus and hydrolysates analysis

为了全面评估枸杞子中的酚类成分,本研究分别利用碱水解和酸水解法制备了其中的结合多酚(non-extractable phenolic compounds, NEPC)。选取Box-Behnken实验设计建立了酸或碱的浓度、水解时间和料液比等与NEPC得率之间的数学模型,并优化了水解工艺参数。碱水解过程中的时间对NEPC得率影响显著,而料液比对酸水解的结果影响较大;最佳工艺条件下,碱水解和酸水解获得的NEPC分别为0.65±0.05 mg/100 g和0.52±0.03 mg/100 g。利用UPLC-Q-TOF-MS,从水解产物中解析了11种化合物,主要是苯丙素衍生物。11种化合物都可在酸水解产物中被检出,而碱水解产物中仅鉴定出4种物质。研究结果表明,碱水解能得到更多的NEPC,酸水解产物则表现出良好的化合物多样性,因此制备NEPC时,应根据不同的研究目的选择水解方法。

In order to comprehensively evaluate the phenolic components in Lycii Fructus,this study prepared non extractable phenolic compounds(NEPC)from Lycii Fructus after removing free polyphenols using alkaline hydrolysis and acid hydrolysis,respectively.The Box-Behnken experimental design method was selected to establish a mathematical model between NEPC yield and hydrolysis conditions,such as acid or alkali concentration,hydrolysis time,and material liquid ratio.The results of the response surface experimental design analysis indicated that in alkaline hydrolysis,the hydrolysis time has a significant impact on the yield of NEPC,but in acid hydrolysis,the ratio of material to liquid in acid hydrolysis has a considerable impact on the outcomes.Under the optimum circumstances,the yield of NEPC were 0.65±0.05 mg/100 g for the alkaline hydrolysis process and 0.52±0.03 mg/100 g for acid hydrolysis procedure,respectively.The chemical components in the hydrolysates were analyzed using UPLC-Q-TOF-MS.Eleven compounds were identified,which were the phenylpropanoids.In conclusion,the acid hydrolysate contained eleven compounds,while the alkali hydrolysis products had only four substances.Alkali hydrolysis produced more NEPC,whereas acid hydrolysate showed a good diversity of chemicals.Hence,different hydrolysis methods should be chosen for different research purposes while preparing NEPC.