超声波辅助萃取-双波长分光光度法测定马齿苋中总黄酮

采用超声波提取法对马齿苋总黄酮进行提取,双波长分光光度法对其进行分析测定。分析测定时,选定测定波长510nm,参比波长576nm,芦丁标准曲线回归方程为△A=9.1426C-0.0057,R2=0.9923,研究表明该方法精密性、重现性好;超声波提取时,通过单因素试验及二次通用旋转组合设计优化确定了马齿苋中总黄酮最佳提取工艺如下:乙醇浓度70%vol,料液比1∶28,超声时间35min,超声温度43℃,在此最佳条件下马齿苋中总黄酮的含量为9.61%。     

超声波提取花椒皮总黄酮工艺及其抗氧化性研究

以花椒为原料,采用超声波辅助法提取花椒果皮中的总黄酮,在单因素试验基础上设计正交试验研究提取最佳工艺条件。结果表明:花椒果皮总黄酮超声提取的最佳工艺条件为料液比1:30(g/mL)、提取时间50min、乙醇体积分数45%。采用紫外分光光度法测定其总黄酮含量,得率可达到3.56%。花椒皮总黄酮清除DPPH自由基和.OH的IC50分别为0.855μg/mL和132.18μg/mL;同时可以看出花椒皮总黄酮也具有很强的还原能力,且高于BHT。     

野菊花中绿原酸与木犀草苷同时超声提取条件优化

利用超声波辅助系统从野菊花中同时提取绿原酸和木犀草苷,通过正交试验设计考察料液比、提取时间、乙醇浓度、提取温度对绿原酸和木犀草苷含量的影响。试验结果显示野菊花中绿原酸和木犀草苷同时提取的最佳工艺条件为:75%乙醇水溶液、料液比1∶400、提取时间90 min、提取温度50℃。在最佳提取条件下野菊花中绿原酸和木犀草苷得率分别可达(8.94±0.03)mg/g和(2.97±0.04)mg/g。     

响应面法优化超声法提取枸杞中总黄酮工艺

采用响应面法优化超声波法提取枸杞中总黄酮的条件。在单因素实验基础上,选择提取过程中的提取时间、超声波功率和液料比为提取因子,进行三因素三水平Box-Behnken中心组合设计,采用响应面法分析(RSM)3个因素对枸杞总黄酮得率的影响。超声波法提取枸杞中总黄酮的最优条件为:乙醇浓度为75%,提取时间为26.63 min、超声波功率295.488 W、液料比27.99∶1(mL∶g),总黄酮得率预测值为0.994 3%,在最优的条件下进行3次验证试验,总黄酮的平均得率为0.9952%,与理论值的相对误差为0.01%,理论值与实验值相吻合,说明该优化方法合理可行。     

黑皮鸡枞菌多糖超声辅助提取条件优化及抗氧化活性研究

目的 响应面法优化超声波提取法提取黑皮鸡枞菌(Oudemansiella raphanipes)多糖的工艺。方法 以黑皮鸡枞菌多糖的提取率为指标,采用超声波提取法从黑皮鸡枞菌中提取多糖,以超声功率、超声提取时间和碱浓度作为单因素变量,利用单因素试验结合响应面法优化确定超声波提取黑皮鸡枞菌多糖的最佳提取工艺。采用乙醇分级法黑皮鸡枞菌多糖进行乙醇分级,并对分级多糖的抗氧化活性进行研究。结果 结果表明优化得到的黑皮鸡枞菌多糖最佳工艺条件为：超声功率151.8 W、超声时间102.0 min和碱浓度0.05 mol/L,在此条件下,黑皮鸡枞菌多糖提取率最高,达到15.40% ± 0.20%,与响应面预测值16.02%相近。此外,5种乙醇分级多糖均具有一定的抗氧化活性。结论 响应面模型是成功的、可行的,80%以上分级多糖的羟基自由基清除率和还原力最强,80%分级多糖的DPPH自由基清除能力最强。     

响应面法优化藜麦糠中多酚超声提取工艺及其抗氧化活性

为了开发利用藜麦糠资源,采用单因素实验与响应面分析相结合的方法,优化了藜麦糠中多酚超声辅助提取工艺,并以BHT为阳性对照,DPPH·和·OH清除率为指标评价其抗氧化活性。结果显示,藜麦糠中多酚超声辅助最佳提取工艺为:乙醇浓度44%,提取时间31 min,提取温度61℃,料液比(g/mL) 1∶43,超声功率200 W。该工艺条件下,藜麦糠中多酚提取率为0.79%。藜麦糠多酚对·OH和DPPH·的清除率均随其浓度增加而增大,量效关系明显,对·OH和DPPH·的IC_(50)分别为13.52μg/mL和2.48μg/mL。表明优化的藜麦糠多酚提取工艺稳定可行,藜麦多酚具有强的抗氧化活性。     

超声辅助提取小米谷糠油工艺优化

本研究探讨了小米谷糠前处理方式和新鲜程度对小米谷糠油提取率的影响，采用超声波辅助技术，选取最适提取溶剂，通过单因素实验和响应面分析优化小米谷糠油提取工艺，并分析了小米谷糠油脂主要理化性质及其脂肪酸组成。结果表明:选用新鲜小米谷糠，经过温度为121 ℃红外加热15 min处理；选择无水乙醇作为最佳提取溶剂，浸提时间为2 h、料液比为1:6.5 g/mL、浸提温度为56 ℃，在此条件下小米谷糠油提取率为78.57%；各因素对小米谷糠油提取率的影响程度的顺序依次为:料液比>浸提温度>浸提时间；该条件下提取的小米谷糠油酸值、过氧化值均符合《食品安全国家标准 植物油》（GB2716-2018）米糠油的指标；小米谷糠油的脂肪酸主要成分为棕榈酸、硬脂酸、油酸、亚油酸和亚麻酸，不饱和脂肪酸含量占总脂肪酸含量的90.58%，其中亚油酸含量高达72.31%。本研究提出的超声辅助无水乙醇提取小米谷糠油工艺路线是可行的，可为小米谷糠进一步开发利用提供重要的理论支撑。     

Investigation of Two-Dimensional Ultrasonic Surface Burnishing Process on 7075-T6 Aluminum

A novel two-dimensional ultrasonic surface burnishing process(2D-USBP)is proposed.7075-T6 aluminum samples are processed by a custom-designed 2D-USBP setup.Parameter optimization of 2D-USBP is conducted to determine the best processing strategy of 7075-T6 aluminum.A uniform design method is utilized to optimize the 2D-USBP process.U13(133)and U7(72)tables are established to conduct parameter optimization.Burnishing depth,spindle speed,and feed rate are taken as the control parameters.The surface roughness and Vickers hardness are taken as the evaluation indicators.It establishes the active control models for surface quality.Dry wear tests are conducted to compare the wear-resistance of the 2D-USBP treated sample and the original sample.Results show that the machin-ing quality of 2D-USBP is best under 0.24 mm burnishing depth,5000 r/min spindle speed,and 25 mm/min feed rate.The surface roughness Sa of the sample is reduced from 2517.758 to 50.878 nm,and the hardness of the sample surface is improved from 167 to 252 HV.Under the lower load,the wear mechanism of the 2D-USBP treated sample is mainly abrasive wear accompanied by delamination wear,while the wear mechanism of the original sample is mainly delamination wear.Under the higher load,the accumulation of frictional heat on the sample surface transforms the wear mechanisms of the original and the 2D-USBP treated samples into thermal wear.     

超声辅助模板电解加工夹具设计及参数优化

在钛合金等难加工材料上加工高质量的群孔结构仍是一个难题,模板电解加工技术是解决此类问题的较理想方法,在其基础上引入了超声辅助技术,以进一步提高加工质量。设计一种专用超声辅助模板电解夹具,通过大量试验寻找关键参数的影响规律。研究结果表明,一定范围内超声频率越低,超声功率越高,则超声辅助优化效果越显著;超声辅助模板电解加工的最佳温度为45℃,最佳电解液压力为0.35 MPa。     

Ultrasonic-assisted enzymatic extraction and antioxidant activity of polysaccharides from Setaria viridis

Ultrasonic-assisted enzymatic extraction (UEAE) and response surface methodology (RSM) were used to isolate polysaccharides from Setaria viridis (SVP). Optimal extraction conditions in the enzymatic hydrolysis process were: extraction duration, 68 min; extraction temperature, 51°C; ratio of enzyme to raw material, 1.6%; and ratio of liquid to raw material, 20 mL/g. Then, following ultrasonic treatment (180 W, 60°C, 60 min), the experimental yield was 8.94 ± 0.38%. Crude SVP was purified by DEAE cellulose-52 chromatography and Sephadex G-100 chromatography, resulting in the isolation of three fractions (designated SVP-1, SVP-2 and SVP-3). These SVPs were mainly composed of glucose residue, and SVP-3 had a significantly higher uronic acid content than the other two fractions. Additionally, all fractions showed strong antioxidant activities in vitro.