超声波萃取苦荬菜叶中β-谷甾醇的工艺优化及其动态积累

Process Optimization of Ultrasonic Extraction ofβ-sitosterol from Leaves of Lactuca indica L.and Its Dynamic Accumulation

为优化超声波辅助提取蒙早苦荬菜(Lactuca indica L.cv. Mengzao)叶中β-谷甾醇的工艺条件,并探究不同生长期叶中β-谷甾醇的含量,本研究采用超声波辅助乙醇提取法,以料液比、超声频率、提取温度和提取时间为影响因素,以β-谷甾醇提取率为考核指标,采用单因素试验法和Box-Behnken方法优化了β-谷甾醇提取工艺,并测定了不同生育阶段蒙早苦荬菜叶的β-谷甾醇含量。结果表明:蒙早苦荬菜叶中β-谷甾醇的最佳提取工艺为提取时间20 min、温度60℃、频率80 KHz、料液比为1∶30 g·mL^(-1)。在此条件下,提取量达到最高,为12.08 mg·g^(-1)。各因素对苦荬菜中β-谷甾醇提取量的影响大小顺序为:料液比>时间>频率>温度。对不同生育期(幼嫩期、营养生长期、开花初期、开花中期、开花末期、结实期)蒙早苦荬菜叶片的β-谷甾醇提取量进行分析发现,开花初期为最佳收获期,β-谷甾醇提取量最高,达13.22 mg·g^(-1)。目前,β-谷甾醇多应用于医疗领域,但都处于探索阶段,仍需进行更为深入系统的研究。

In order to optimize the process conditions for the ultrasound-assisted extraction ofβ-sitosterol from leaves of Lactuca indica L.cv.Mengzao,and to explore the content ofβ-sitosterol in leaves at different growth stages.Theβ-sitosterol extraction process was optimized by ultrasound-assisted ethanol extraction using the one-way test method and Box-Behnken method,with the material-liquid ratio,ultrasound frequency,extraction temperature and extraction time as the influencing factors,and theβ-sitosterol extraction rate as the assessment index.Theβ-sitosterol content of L.indica leaves at different growth stages were also determined.The results showed that the optimal extraction process forβ-sitosterol in L.indica leaves was 20 min extraction time,60℃,80 KHz frequency,and 1∶30 g·mL^(-1) material-liquid ratio,under which the highest extraction amount of 12.08 mg·g^(-1) was achieved.And the order of the effect of each factor on the extraction amount ofβ-sitosterol in L.indica was as follows:material-liquid ratio>time>frequency>temperature.The amount ofβ-sitosterol extracted from L.indica leaves at different stages(young,nutritive,early flowering,mid-flowering,end-flowering,and fruiting)was analyzed,and the early flowering stage was the optimal harvesting stage,with the highest amount ofβ-sitosterol extracted,which was 13.22 mg·g^(-1).At present,β-sitosterol is mostly used in the medical field,but all of them are in the exploratory stage,and more in-depth and systematic researches are still needed.