Effect of Process Parameters of Microwave Assisted Extraction (MAE) on Polysaccharides Yield from Pumpkin

Process parameters of microwave assisted extraction （MAE） of the polysaccharides from pumpkin viz. extraction temperature, time and liquid-solid ratio were studied by using single factor and response surface methodology method. The results showed that the liquid-solid ratio was the most important factor in polysaccharides yield, followed the extraction temperature was the least important factor. The optimum microwave assisted extraction co by ndi extraction time, and tions for the highest polysaccharides yield from pumpkin （16.76%-4-0.38%） were obtained by using the response surface methodology with extraction time of 29 min, an extraction temperature of 79 ℃ and a liquid-solid ratio of 22 mL·g^-1. Validation experiment result well agreed with predicted value.

Microwave-assisted Extraction of Rutin and Quercetin from Flos Sophorae

Three microwave-assisted extraction(MAE) procedures were studied. The first procedure was household microwave oven dynamic extraction(HMODE). The second procedure was special microwave oven bath extraction(SMOBE). The third procedure was microwave resonant cavity dynamic extraction(MRCDE). The results obtained by the three microwave-assisted extraction procedures were compared with those obtained by using traditional Soxhlet extraction. The results indicate that the MAE not only took a shorter time, but also simplified the procedure, and made the extraction a higher yield. At the same time the results obtained by the three MAE procedures were also compared with each other.

Response surface optimization of microwave-assisted extraction for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii

Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii.The optimized extraction procedure was achieved by soaking the sample with 70% methanol（1∶15,v/v）for 30 min,and then microwave irradiation for 11 min at a power of 600 W.Coupling the extraction process with HPLC-fluorescence presented good recovery,satisfactory precision,and good linear relation.Compared with a method from the Chinese Pharmacopoeia,the proposed method enables higher extraction efficiency and more accurate analytical results.It can be of potential value in quality assessment of Radix Puerariae thomsonii medicinal materials.

Study on microwave-assisted extraction of coal

The effect of different factors on coal extraction yield-temperature, solvent, coal type and irradiation time were investigated for different China coals under microwave-assisted extraction（MAE）. The results show that the optimum temperature for ethanol, acetone and THF are 393,373 and 373 K respectively and the extraction yield of THF is higher than that of other two solvents under MAE. Extraction with several single organic solvents were conducted for the 5 typical China coals-Shenfu, Tongchuan, Panzhihua, Yitai and Huating coal under microwave-assisted extraction and Soxhlet extraction. Results indicat that extraction yield of ethylenediamine, ethanol, acetone, tetrahydrofuran under MAE are all higher than that of Soxhlet extraction and MAE required less time. Tongchuan coal extracts of ethanol and acetone which were extracted by MAE and Soxhlet extraction were analyzed by GC/MS.

Optimization of the microwave-assisted extraction of phlorotannins from Saccharina japonica Aresch and evaluation of the inhibitory effects of phlorotannin-containing extracts on HepG2 cancer cells

The use of a microwave-assisted extraction （MAE） method for the extraction ofphlorotannins from Saccharinajaponica Aresch （S.japonica） has been evaluated with particular emphasis on the influential parameters, including the ethanol concentration, solid/liquid ratio, extraction time, extraction temperature, and microwave power. The MAE procedure was optimized using single-factor design and orthogonal array design （OAD）. The content of total phlorotannins in S. japonica was determined using a Folin-Ciocalteu （FC） assay. A maximum total phlorotannin content of 0.644 mg of phloroglucinol equivalent per gram of dry weight plant （mg PGE/g DW） was obtained using the optimized model, which included an ethanol concentration of 55%, solid/liquid ratio of 1：8, extraction time of 25 min, irradiation power of 400 W, and temperature of 60~C. Under similar conditions, the application of a conventional extraction method led to a lower phlorotarmin yield of 0.585 mg PGE/g WD. These results demonstrated that the MAE approach provided better results for the extraction ofphlorotarmins from S.japonica and was a promising technique for the extraction of phenolic compounds from S. japonica and other materials. In addition, screening tests for the inhibitory activity showed that the phlorotannin-containing extracts significantly inhibited the growth of human hepatocellular carcinoma cells （HepG2） by inducing their apoptosis. The morphological changes that occurred during cell apoptosis were characterized using Hoechst33258 staining.

茶饮料浸提工艺的微波辅助萃取(MAE)应用研究

浸提工艺是茶饮料生产过程一个关键生产工艺。本文比较了传统热水浸提工艺和微波辅助萃取工艺之间的最优工艺参数,并利用高效液相色谱分析方法研究了微波萃取对茶多酚浸出得率和单体组成的影响,表明微波萃取技术(Microwave-assistedextraction,MAE)可应用在茶饮料生产中,而且比传统热水浸提工艺省时节能。结果表明:传统热水浸提工艺的最优浸提温度90℃、时间43min、液固比20:1,茶多酚的得率为19.76%;微波辅助萃取工艺的最优浸提功率360W、时间3.5min、液固比25:1,茶多酚的得率为20.63%。微波短时处理茶叶不会对茶多酚的结构和单体组成产生破坏性影响。

MAE法萃取薄荷挥发油的研究

以正戊烷为溶剂,采用微波协助萃取技术(MAE),对影响薄荷挥发油萃取的4个因素进行了研究。结果表明:影响薄荷挥发油萃取各因素由强到弱排序依次为溶剂用量、微波处理时间、烘干温度、溶剂浸泡时间。20 g薄荷干粉采用溶剂浸泡时间3 h,溶剂用量400 mL,微波处理时间30 s,薄荷烘干温度为50℃的工艺参数组合,所获得的薄荷挥发油量最高,为352.10 mg,萃取率达1.76%。

微波辅助提取技术(MAE)研究和应用进展

微波辅助提取技术与传统技术相比在很多方面有其独特的优越性。本文综述了微波辅助提取技术的机理、特点、设备以及近几年来微波辅助提取在有机污染物、生化活性物质、金属等方面的研究和应用进展的研究报导。最后展望了微波辅助提取的发展前景。

MAE-SAFE-GC-MS法分析道口烧鸡挥发性成分

采用微波辅助萃取耦合溶剂辅助风味蒸发法对道口烧鸡的挥发性成分进行提取。采用气相色谱-质谱结合保留指数定性分析道口烧鸡挥发性成分,共鉴定出98种化合物,包括11种醇、17种醛、9种酮、11种含氮、含硫及杂环化合物、3种酸、5种酯、4种醚、36种烃和2种酚。可能对道口烧鸡特征香气的形成起关键作用的有4-萜烯醇、糠醇、肉桂醇、己醛、苯甲醛、反-2-癸烯醛、2,4-癸二烯醛、大茴香醛、肉桂醛、丁香酚、茴香脑、肉豆蔻醚、2,3-二氢-3,5-二羟基-6-甲基-4H-4-吡喃酮等。

MAE-SAFE/GC-MS分析酱牛肉挥发性成分

采用微波辅助萃取耦合溶剂辅助风味蒸发法提取酱牛肉挥发性成分,利用气相色谱-质谱联用仪结合保留指数定性分析酱牛肉的挥发性成分,共鉴定出65种化合物,包括11种醇,10种醛,3种酮,8种含氮、含硫或杂环化合物,9种酸,6种酯,3种醚,14种烃和1种酚。采用嗅闻频率检测法对酱牛肉挥发性成分进行GC-O分析,嗅觉检测频率≥5/11的化合物有壬醛、5-甲基糠醛、薄荷酮、茴香脑、麦芽酚、反-肉桂醛、肉桂醇。

石油醚结合MAE技术萃取薄荷挥发油的研究

对影响薄荷挥发油萃取的浸泡时间、溶剂用量、微波处理时间和烘干温度4个因素进行了研究。结果表明,各因素对挥发油萃取率的影响由强到弱依次为:浸泡时间>烘干温度>溶剂用量>微波处理时间。薄荷挥发油萃取最佳组合为A3B3C2D1,即浸泡时间5h、溶剂用量600mL、微波处理时间40s、烘干温度30℃。该组合挥发油萃取率为2.23%。

MAE-HS-SPME联合萃取GC-MS分析肉桂香气成分

采用微波辅助萃取与顶空-固相微萃取联合(MAE-HS-SPME)的方法萃取肉桂中香气成分,用气相色谱-质谱(GC-MS)法进行分析,并将分析结果与同时蒸馏萃取法(SDE)和HS-SPME法对比。结果表明,MAE-HS-SPME的最佳条件为:称取10g样品,加入100mL去离子水,微波功率为150W,用100μmPA萃取头萃取4.5min,250℃解吸20s。GC-MS分析确认了其中62种成分,占总峰面积的95.01%。3种萃取方法所得肉桂中主要香气成分基本相同,均为桂醛、α-荜澄茄烯、反式茴香脑和4,7-二甲基-1-异丙基-[1α,4aα,8aα]-1,2,4a,5,6,8a-六氢萘等。MAE-HS-SPME法鉴定的成分比HS-SPME和SDE法分别多出18种和26种。说明MAE-HS-SPME是一种分析肉桂中香气物质的高效的样品前处理方法。

MAE-LC-AFS测定鸡蛋中阿散酸、洛克沙砷、硝苯砷酸

建立微波辅助萃取-液相色谱-原子荧光光谱法(Microwave Assisted Extraction-Liquid Chromatography-atomic Fluorescence Spectrometry,MAE-LC-AFS)测定鸡蛋中阿散酸(Arsanilic,ASA)、洛克沙砷(Roxarsone,ROX)、硝苯砷酸(Nitarsone,NIT)的分析方法。研究并优化液相色谱和原子荧光的工作条件。在0~2.0 mg/L范围内阿散酸、硝苯砷酸和洛克沙砷的线性关系良好,线性相关系数大于0.999,阿散酸、硝苯砷酸、洛克沙砷检出限(S/N=10)分别为0.1、0.2、0.2 mg/kg。阿散酸在0.1、0.2、0.5 mg/kg 3个加标水平下的平均回收率为80.5%~91.0%,相对标准偏差为3.14%~3.77%;硝苯砷酸和洛克沙砷在0.2、0.5、2 mg/kg,3个加标水平下平均回收率为81.0%~91.1%和82.5%~104.9%,相对标准偏差为2.72%~4.02%和1.81%~7.52%。

MAE-分光光度法测定大白口蘑中总黄酮含量

[目的]采用微波辅助萃取(MAE)法提取、以分光光度法测定大白口蘑样品中的总黄酮含量。[方法]通过单因素试验和正交试验考察乙醇浓度、液固比、微波功率、微波时间等因素对微波辅助萃取法提取大白口蘑黄酮提取率的影响。对微波法与乙醇浸提法、超声波萃取法进行了比较。[结果]微波萃取法最佳提取条件:乙醇浓度60%、液固比40∶1、微波功率255 W、微波时间5 min。最优条件下,精密度和回收率试验所得结果的相对标准偏差为1.24%(n=6),回收率在98.1%～103.7%。微波法优于乙醇浸提法和超声波萃取法。[结论]MAE-分光光度法简单、可靠,重现性好,稳定性好,可广泛用于各种食用菌中黄酮类物质含量的测定。

MAE-SPME萃取绞股蓝化学成分技术及含量测定的研究

通过气相色谱-质谱法对绞股蓝挥发性成分的鉴定和其相对含量的测定,建立了绞股蓝挥发性成分萃取方法,优化了微波辅助提取-固相微萃取联用技术的萃取条件,共鉴定出化合物48种,包括酮、醇、酸、烃、酚、糖、醛、酯、醚、酰胺及杂环化合物等11类化合物,其中糖类占已确认化合物总量的25.06%,酮类化合物21.73%,烃类占15.01%,醛类占14.31%,醇类占13.86%,酸类占13.45%,酯类占10.93%。结果表明,该技术可以简便、快捷、准确地进行绞股蓝挥发性成分的分析鉴定。

MAE技术提取银杏叶总黄酮的研究

以银杏叶为材料,研究利用MAE技术提取总黄酮的方法.以水为溶剂,以微波辐射为辅助条件,提取银杏叶总黄酮,通过与常规水浸提法进行对比,总黄酮得率提高约1.7倍,而提取时间大大缩短.并考察了固液比、微波辐射功率、微波辐射时间和水浸提时间等因素对银杏叶总黄酮得率的影响;实验确定了合理的提取工艺条件,即固液比(g:mL)为1∶30、微波功率为600 W、辐射时间为20 min、水浴浸提时间为3 h.

MAE-GC/MS法测定食品中B(α)P

建立了测定食品中苯并芘（B（α）P）含量的MAE-GC/MS法.样品经微波辅助萃取技术前处理,DB-5MS弹性石英毛细管柱（30 m×0.25 mm×0.25 μm）分离,以B（α）Pm/z=252为选择离子,串连四极杆选择离子检测模式检测,再以9-苯基蒽为内标,采用内标法定量.结果显示,B（α）P的检出限为0.01 μg/kg,标准曲线线性范围为0～ 10 μg/mL,相关系数为1.000,方法回收率达97％～ 103％;精密度良好：日内RSD＜0.5％,日间RSD＜1％;准确度良好：以阴性样品为基底物质,在0.1 mL甲醇苯并芘成分分析国家标准物质（GBW08702）的加标水平上,测定值在其标准值范围内.表明：该法前处理简单,回收率高,检出限、线性范围、准确度、精密度结果均满足要求,可用于测定食品中的B（α）P含量.

MAE-QuEChERS-GC法测定土壤中4种有机氯农药

建立了微波萃取土壤中艾氏剂、七氯、狄氏剂和异狄氏剂4有机氯农药,结合QuEChERS净化和气相色谱定量的分析方法。样品经丙酮-正己烷(V丙酮∶V正己烷=1∶1)提取,从线性、检出限、定量限和精密度等方面考察了方法的性能。4种有机氯的质量浓度在0.005~0.500μg/L范围内与峰面积呈良好的线性关系,相关系数均≥0.998,方法检出限为0.04~0.07μg/kg,样品加标回收率为90%~101%,测定结果的相对标准偏差为1.60%~5.60%(n=6)。该方法操作方便、快速,结果准确、可靠,试剂用量少,缩短了分析时间,适用于土壤中有机氯的测定。

基于深度流形学习的人脸年龄识别

现有的人脸年龄识别方法大多利用深度学习框架提取人脸特征来识别年龄,但深度学习方法提取的高维人脸特征往往包含大量的冗余信息,不利于人脸年龄的识别。为了提高人脸年龄识别算法的精度和鲁棒性,提出了一种基于深度流形学习(Deep Manifold Learning, DML)的算法,采用深度学习提取人脸特征,通过流形学习选择具有判别性的人脸特征,将深度学习提取的高维人脸特征嵌入到低维的判别子空间上识别年龄。在公开的人脸数据库MORPH和FG-NET上对DML算法进行了实验,结果表明DML方案平均绝对误差(Mean Absolute Error, MAE)大幅度降低,不同误差值下识别累积评分(Cumulative Score, CS)明显提高,显著优于当前流行的人脸年龄识别方法。