红薯叶黄酮类化合物的提取及其抗氧化活性的测定

采用不同方法提取红薯叶中的黄酮类化合物,通过比较提取率及黄酮类化合物的含量,确定用体积分数为60%的乙醇提取为最佳的提取方法,同时采用烘箱贮存法测定了红薯叶黄酮类化合物在猪油中的抗氧化活性.结果表明,红薯叶黄酮类化合物具有明显的抗氧化效果,且抗氧化活性随用量的增加而增强,抗氧化效果好于抗坏血酸和柠檬酸.     

香樟叶中黄酮类化合物提取方法和抗氧化性的研究

通过各种方法提取香樟叶中的黄酮类化合物,比较不同提取方法的提取效率及提取物中黄酮类化合物的含量,从而得到最佳的提取方法。结果表明,体积分数60%乙醇提取法是较好的提取方法。并采用烘箱贮存法测定了该叶片黄酮提取物在猪油中抗氧化活性。结果表明:香樟叶片黄酮提取物具有明显的抗氧化效果,且抗氧化性随添加量的增加而增强。     

肉苁蓉中黄酮类化合物的提取及抗氧化性能研究

利用“超声波震荡法”和“索氏提取法”分别提取了肉苁蓉中的总黄酮类化合物,并对其含量及抗氧化性能进行了分析.测定结果表明超声波振荡法提取肉苁蓉中总黄酮类化合物的含量高于索氏提取法提取的含量.通过实验测定回收率在96.85％ ～ 99.46％,精密度较高,样品液在2h内很稳定,说明紫外可见分光光度法准确度较高,偏差小,实验条件易控制.用荧光法对肉苁蓉中黄酮类化合物抗氧化性的分析和测定,清除率为91.5％,说明肉苁蓉中黄酮类化合物具有很强的抗氧化性.实验中发现用荧光分析法测定提取物中总黄酮类化合物的抗氧化性具有快速、简便、灵敏度高、重现性好等优点.     

毛白杨雄花序中总黄酮的提取工艺优化试验研究

用正交试验法研究了毛白杨雄花序中总黄酮类化合物的最佳提取工艺，确定了提取的最优工艺条件为：提取温度80℃，提取时间150min，液料比25：1，乙醇浓度60％，提取一次。在此条件下黄酮得率达2．58％。     

甜茶叶中黄酮类化合物提取条件研究

用正交实验方法考察了甜茶叶中黄酮类化合物的最佳提取条件。研究结果表明，在80℃条件下，用6倍于叶重的70％乙醇加热提取3次，每次50min，甜茶叶中黄酮类化合物提取的效果最好。     

饿蚂蝗中黄酮类化合物的抗氧化活性的研究

提取了饿蚂蝗中的黄酮化合物,并研究了其含量及与体外抗氧化活性关系。用体积分数为75%的乙醇提取饿蚂蝗全草黄酮化合物,并采用HPD-100大孔树脂对粗提液进行精制,利用NaNO2-Al（ NO3）3-NaOH显色法和可见分光光度法测定精制黄酮的含量。采用DPPH和ABTS自由基测定法,对饿蚂蝗黄酮化合物的抗氧化活性进行评价。结果表明：在自由基清除实验中,精制饿蚂蝗黄酮类化合物自由基清除能力高于未精制的乙醇提取物。饿蚂蝗黄酮类化合物的体外抗氧化活性与黄酮含量呈正相关性。     

正交实验设计优化穿心莲总黄酮提取工艺

探讨了用乙醇回流提取穿心莲黄酮类化合物,找出最佳提取条件。通过正交实验探索乙醇回流法提取穿心莲黄酮类化合物的最佳工艺条件,采用紫外分光光度法测定总黄酮含量。影响实验因素的主次顺序是：固液比〉浸提时间〉乙醇浓度〉浸提温度,其中固液比对实验指标有显著性的影响。最佳提取工艺为固液比1：20、浸提时间4h、乙醇浓度60％、浸提温度50℃。     

新刊导读

食品及饲料添加剂杨梅叶黄酮类化合物最佳提取工艺研究/胡静丽等//食品科学.-2003,24(1).-96～99 为确定杨梅叶中黄酮类化合物的提取工艺,用乙醇溶液浸提,结合超声波辅助方法,萃取杨梅叶中的黄酮类化合物,探讨了影响提取率的主要因素,最后用正交法确定了好的提取工艺。结果表明:在45倍于样重的40％的乙醇浸泡24h后,超声波辅助萃取45min,连续提取2次,黄酮的总浸出率可达99.30％,杨梅叶中的黄酮含量为8.16％。     

甜茶叶中黄酮类化合物提取条件研究

用正交实验方法探讨了甜茶叶中黄酮类化合物的最佳提取条件。研究结果表明：在80℃条件下，用6倍于叶重体积的70％醇加热提取3次，每次50min，甜茶叶黄酮提取效果最好。     

火棘果中黄酮类化合物的提取工艺研究

以乙醇为提取溶剂,通过单因素试验和正交试验方法探究火棘果中黄酮类化合物的提取工艺,并采用分光光度法测定了黄酮类物质的含量。结果显示,火棘果中黄酮类化合物的最佳提取工艺为乙醇浓度为80%、固液比为1∶20、提取温度为70℃、提取时间为4 h。在最佳条件下,火棘果中黄酮类化合物的提取率为1.316%。     

微波提取蕨菜总黄酮及其抗氧化性研究

为了探明蕨菜中总黄酮类物质微波提取工艺及其抗氧化性,为其进一步的利用开发提供依据,以蕨菜为原料,采用单因素正交实验结合,研究了微波温度、提取时间、乙醇浓度、料液比等工艺参数对总黄酮含量的影响。结果表明蕨菜总黄酮的微波萃取工艺为:萃取温度70℃、乙醇浓度80%、萃取时间10min、固液比1:40,该条件下的提取率为1.78%。蕨菜总黄酮的抗氧化性随着浓度的升高而增强,当总黄酮浓度为0.89mg/L时,羟基自由基(·OH)清除率为65.1%,当总黄酮浓度为11.15mg/L时,对DPPH自由基的清除率达86.5%。     

Chelatometric salting-out extraction and characteristics of flavonoids from Folium nelumbinis based on an ethanol/K2HPO4 system

A new salting-out extraction method, namely chelatometric salting-out extraction, was established for rapidly extracting flavonoids from Folium nelumbinis. Borax was used as a chelating agent and an ethanol/K₂HPO₄ system as the salting-out extraction system. The maximum flavonoid concentration in the top phase was observed at an ethanol concentration of 43.0% and an amount of salt of 2.45 g under the experimental conditions. The pH value of the system and extraction time had no obvious influence on the extraction efficiency of flavonoids. The results also showed that the extraction efficiency of flavonoids exceeds 90.4% at the first time extraction. Moreover, the antioxidant activities of flavonoids were evaluated by DPPH? radical assays.     

肉桂总黄酮提取工艺及其抗氧化性研究

以肉桂为原料,进行了肉桂总黄酮提取工艺及其抗氧化活性的研究,建立了以芦丁为标准品,NaNO2-Al(NO3)3-NaOH为显色剂,分光光度法测定肉桂总黄酮含量的分析方法。结果表明,肉桂总黄酮提取的优化工艺为乙醇浓度60%,肉桂与溶液的比1∶60(g/mL),回流温度70℃,提取时间6 h,总黄酮提取率达16.10%,含量达70.02%。肉桂总黄酮的抗氧化性随着浓度的升高而增强,当总黄酮浓度为4.5 mg/mL时,OH自由基清除率达40.49%;当总黄酮浓度为2.0 mg/mL时,DPPH自由基清除率达94.29%。     

Ethanol modified supercritical carbon dioxide extraction of flavonoids from Momordica charantia L. and its antioxidant activity

Ethanol modified supercritical carbon dioxide (SC-CO₂) extraction of flavonoids from Momordica charantia L. fruits and its antioxidant activity were performed. The influences of parameters such as temperature, extraction time and pressure on the yield of flavonoids were investigated. The antioxidant activities of flavonoids were assessed by means of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay and β-carotene bleaching test. The experimental data obtained indicated that pressure, temperature and time had significant effect on the extraction yield. The optimum extraction conditions, determined by the 3D response surface and contour plots derived from the mathematical models, were as follows: extraction temperature 46 °C, pressure 33.4 MPa, and extraction time 53.2 min. Under these conditions, the experimental value was 15.47 mg/g, which was well matched with value predicted by the model. The antioxidant activity of flavonoids obtained by ethanol modified SC-CO₂ extraction method had higher antioxidant activity than the flavonoids extracted by conventional solvent extraction (CSE) method. The DPPH radical-scavenging ability of flavonoids obtained by ethanol modified SC-CO₂ extraction method reached to 96.14 ± 1.02%, equivalent to the clearance rate of ascorbic acid at 1.2 mg/mL. Results indicated that ethanol modified SC-CO₂ extraction was a suitable approach for the selective extraction of flavonoids from M. charantia L.     

Extracts from pitanga (Eugenia uniflora L.) leaves: Influence of extraction process on antioxidant properties and yield of phenolic compounds

Different extraction processes were employed to extract the polyphenolic compounds from pitanga (Eugenia uniflora L.) leaves: a one-step process using water, ethanol or supercritical CO₂ as solvents, and a two-step process using supercritical CO₂ followed by either water or ethanol. The total polyphenolic compounds, total flavonoids and antioxidant activity were determined in all the extracts obtained. The process performance was evaluated with respect to three variables: global extraction yield, concentration and yield of both polyphenols and flavonoids in the extracts. For the one-step extraction, the results showed that the extraction yield increased with solvent polarity. For the two-step process, the results suggested that water was more efficient in extracting the phenolic compounds from E. uniflora when the matrix was previously extracted with scCO₂. With respect to the antioxidant activity, the ethanolic extracts obtained from both processes, using either the DPPH radical scavenging method or the β-carotene bleaching method, presented high antioxidant activities.     

Comparative study on the flavonoids extraction rate and antioxidant activity of onions treated by three different drying methods

Onions, rich in flavonoids, with antioxidant, antibacterial, and other biological activities, are often used as extraction of raw materials to obtain health products with high flavonoids content. However, the amount of raw material consumption is large due to low yield of extracts from fresh onions. As a result, dried onions often are used as extraction materials. The effects of air drying (AD), freeze-drying (FD), and microwave freeze-drying (MFD) on the flavonoids extraction yield of onions were investigated. The most effective and economical method was hot AD. On the other hand, the flavonoids extraction rate of onions dried by MFD was the fastest. FD could also obtain high extraction rate, but it cost the highest energy consumption. In order to obtain relatively rapid, economic, and effective extraction of onion flavonoids, onions can be dried by MFD or AD method.     

不同萃取技术获得的Artemisia sp的甲醇提取物其抗氧化和抗菌活性的比较

The polyphenol content,antioxidant and antimicrobial activities of the extracts obtained by classical, ultrasonic and Soxhlet extractions from dry aerial parts of two Artemisia species(Artemisia vulgaris and Artemisia campestris)were compared.Ultrasound positively affected the yield of extractive substance and the kinetics of extraction,but the extract obtained by the classical extraction showed the highest antioxidant activities and contained higher total contents of phenolic compounds and flavonoids than the extracts obtained by two other extraction techniques.Both flavonoid aglycones(apigenin,quercetin,quercetin 3,3′-dimethyl ether)and flavonoid glycosides(rutin,hyperoside and kaempferol 3-rhamnoside)were identified by thin layer chromatograph(TLC)analysis in the extracts from both species.A.campestris extracts were richer in quercetin than A.vulgaris and its antimicrobial activity was also better than A.vulgaris.Extracts obtained from both species were found to be more effective on the tested yeasts than bacteria.The kinetics of the total extractive substances,such as phenolic,flavonoids and quercetin extraction,was successfully described by the model of unsteady-state diffusion.     

不同提取工艺的马尾松松针提取物抗氧化性能研究

研究超临界二氧化碳萃取、内置超声提取、外置超声提取、普通醇提4种不同提取工艺制备的马尾松松针提取物（SCDEP、IUEP、OUEP,EEP）,分析4种提取物内总酚和总黄酮含量差异;同时研究4种松针提取物的抗氧化性能。结果表明：SCDEP提取物中总酚与总黄酮含量分别为22．18％和4．96％,含量最高;而EEP中总酚和总黄酮含量最低,分别为13．47％和2．98％。4种提取物具有较强抗氧化能力,SCDEP、IUEP、OUEP清除DPPH自由基和还原三价铁能力均强于丁基羟基甲苯（BHT）,而EEP还原三价铁能力弱于BHT。马尾松松针提取物中总酚及总黄酮含量与抗氧化性具有明显的量效关系。     

大果栘依总黄酮的提取与抗氧化性研究

为了探讨大果栘依中总黄酮的提取工艺及体外抗氧化性,采用超声提取法。在乙醇浓度、液料比、提取时间、提取温度四个单因素实验的基础上,通过L9(34)正交实验,比较各因素对提取率的影响,优化大果栘依总黄酮的提取工艺。同时,对大果栘依总黄酮进行显色定性,并测定大果栘依总黄酮对DPPH、羟基自由基、超氧阴离子的清除作用。最佳提取工艺为:乙醇浓度60%、液料比25∶1 mL/g、超声时间20 min、提取温度50℃,此条件下的提取率达到4.12%;随着大果栘依总黄酮浓度的升高,对DPPH、羟基自由基、超氧阴离子的清除率逐渐升高。