Comparison of techniques for extraction of isoflavones from the root of Radix Puerariae: Ultrasonic and pressurized solvent extractions

Radix Puerariae (RP), a traditional Chinese medicinal herb, has been used for a variety of disease prevention and treatment purposes. Three isoflavones, puerarin, daidzin and daidzein, isolated from RP are responsible for its broad therapeutic effects. In the present study, we demonstrate the application of three extraction methods, traditional, pressurized solvent extraction (PSE) and ultrasonic techniques, for preparing ethanolic RP extract. A comparison of the three extraction methods showed preferential higher yields of the three major isoflavones when the ultrasonic technique was applied. The extraction yield became higher as the mean size of RP particles decreased while the total accumulated power varied from 20 to 80 MJ at the solid-to-solvent ratios of 1:5 and 1:10 (g/ml). The relationship among accumulated energies, extraction yields and mean particle sizes under different extraction ratios using ultrasound was also discussed. This study proves that using the ultrasonic method should be the most economic way for enhancing the extraction yield of isoflavones-containing herbal extract in a short time with a reduced amount of solvent at a lower temperature.     

Effect of the fermentation of whole soybean flour on the conversion of isoflavones from glycosides to aglycones

The effect of fermentation of whole soybean flour (WSF) on the conversion of isoflavone glycosides to the aglycone form was analysed by liquid chromatography. WSF (200 g) with 35% moisture, was autoclaved at 121 °C for 20 min (AWSF), cooled and inoculated with 2 mL of spores of the fungus Aspergillus oryzae CCT 4359, and then incubated for 24 h and 48 h. The fermented flour was dried in a vacuum oven and 10 g of each flour, non-fermented and fermented, sieved and defatted. One gram of each flour was used for extraction of the isoflavones with 10 mL of an 80% methanol solution. Aliquots were injected into the HPLC under the following conditions: C18 column, 30 °C, gradient elution, mobile phase of (A) water: 5% acetic acid (v/v) and (B) methanol. The results showed that the FAWSF-48 h contained predominantly isoflavone aglycones (75.51%) when compared to the AWSF (6.94%) and WSF (2.67%).     

豆粕中大豆异黄酮的醇提工艺

主要探讨豆粕中大豆异黄酮的最优醇提工艺.采用正交实验考察乙醇浓度、乙醇用量、提取温度、提取时间四因素对豆粕中大豆异黄酮的影响;采用高效液相色谱法测定染料木素、大豆苷元含量.结果最佳工艺条件为:原料用14倍体积的70%乙醇在70℃提取1h.     

豆粕中大豆异黄酮提取工艺的优化

采用乙醇回流浸提和HCl水解两步法，从大豆豆粕中提取大豆异黄酮类化合物，以染料木素为标准物，在紫外区对异黄酮含量进行测定。通过正交试验确定最佳提取工艺。本实验平均回收率为95．7％。     

Supercritical fluid extraction of daidzein and genistein isoflavones from soybean hypocotyl after hydrolysis with endogenous β-glucosidases

An optimal condition of supercritical fluid extraction (SFE) for isoflavone aglycones (daidzein and genistein) in soybean hypocotyls previously subjected to thermohydration at pH 5.0 and a temperature of 50 °C for 6, 12 and 18 h was developed. Different temperatures, pressures and cosolvents (methanol, ethanol, and acetonitrile) was tested and compared with solid–liquid extraction using aqueous methanol solution (80% v v⁻¹) conducted in parallel for comparison. The extraction conditions were 50–70 °C, 176–380 bar, adding 0, 5, 10 mol% of cosolvents 80% in water as a modifier. The results from SC–CO₂ showed that the cosolvent and pressure have significant effects in the extraction efficiency. It was found that the extraction conditions promoting the highest extraction of daidzein and genistein were at the temperature of 60 °C, pressure of 380 bar and both static and dynamic extraction of 15 min with the addition of 10% acetonitrile (80% v v⁻¹). The maximum amounts of daidzein and genistein extracted by each method were solid–liquid extraction (70.07 mg 100 g⁻¹) and carbon dioxide–acetonitrile (17.97 mg 100 g⁻¹). The yield of daidzein and genistein achieved by a 30 min SC–CO₂ extraction on soybean hypocotyls after 12 h soaking time was markedly improved by the addition of a modifier (acetonitrile) to the CO₂ fluid. HPLC analysis of the obtained extracts revealed that extraction of isoflavone aglycones by SC–CO₂ was 4.78 and 13.19 mg 100 g⁻¹ for daidzein and genistein, respectively. The contents of daidzein and genistein obtained in the solid–liquid extraction were superior to 86% and 63%, respectively, compared to supercritical extraction.     

Optimization of ethanol extraction and further purification of isoflavones from soybean sprout cotyledon

Isoflavones from cotyledons of soybean sprouts were extracted with aqueous ethanol and further concentrated to obtain a product with a high concentration of isoflavone. The ethanol concentration, extraction time and reaction temperature were optimized by using response surface methodology (RSM). Isoflavones in aqueous ethanol were concentrated by a three-step procedure comprised of solid phase extraction (SPE) with Diaion HP-20 and Amberlite-XAD-2 adsorption columns, acid hydrolysis, and liquid–liquid extraction. The maximum amount of isoflavone in aqueous ethanol extracts (11.6 mg/g solid) was obtained when isoflavones in cotyledons (2.18 mg/ g solid) were extracted with 80–90% (v/v) aqueous ethanol above 90 °C for more than 100 min. The isoflavone extracts, obtained by SPE with a Diaion HP-20 column contained 100 mg/g solid. The liquid–liquid extraction (LLE) with ethyl ether further concentrated the extracts up to 229 mg/g solid, retaining 63% of the initial isoflavones.     

豆渣中大豆异黄酮的提取工艺初探

以乙醇为溶剂,对豆渣中大豆异黄酮的提取工艺进行初步研究.试验结果表明,乙醇浓度、提取温度、回流时间、料液比对豆渣中大豆异黄酮的提取均有影响,豆渣中大豆异黄酮的提取工艺为:乙醇浓度为80％,提取温度60～70℃,回流时间为3～4 h,料液比在1:12～1:16之间.     

Comparison of extraction conditions for phenolic,flavonoid content and determination of rosmarinic acid from Perilla frutescens var. acuta

Perilla frutescens var. acuta has traditionally been used to treat disease including, depression, inflammation and tumors. Especially, the presence of rosmarinic acid can induce beneficial and health promoting effects. According to, this work was conducted to comparison of various extraction conditions (extraction process, solvent and time) of total phenolic, floavonoid and rosmainic acid contents from the leaves of Perilla frutescens var. acuta. Also, rosmarinic acid was determined in leaves of Perilla frutescens var. acuta by high‐performance liquid chromatography (HPLC) and the described method was ideally suited for rapid routine analysis. The highest yield of total phenolic, flavonoid and rosmarinic acid was shown 12.15 mg gallic acid equivalents g^?1 dry weight (DW), 7.23 mg rutin equivalents g^?1 DW and 3.76 mg g^?1 DW, respectively. The best condition for extraction efficiency of total phenolic, flovonoid and rosmarinic were found to be: ethanol concentration of 70%, extraction time of 24 h and extraction process of refluxed extraction.     

Pressurized fluid extraction of pistachio oil using a modified supercritical fluid extractor and factorial design for optimization

A pressurized fluid extraction (PFE) method for the extraction of pistachio oil was developed mainly as an analytical tool to determine oil content and/or its quality. The supercritical fluid extractor was modified to be able to pump liquid solvent and CO₂ into the extraction vessel alternatively. The extraction yield was found independent of the pressure in the range 10-150 bar tested. The addition of crushed glass increased the extraction yield by more than 15 g/100 g, while the extraction reproducibility expressed by percentage RSD was improved from 4 to 1. Furthermore, the use of crushed glass reduced the solvent consumption from 35 to 20 mL. The effective variables of temperature (40-80 °C), solvent volume (5-25 mL), and crushed glass percentage (30-60 g/100 g) were optimized by a factorial design method. The model allows the prediction of the extraction yield at different conditions. The PFE yield (i.e. 52.6 g/100 g) and fatty acid composition of pistachio oil were found similar to Soxhlet extraction and their variations were within the experimental uncertainty verified by statistical t-test analysis. Two different solvents of n-hexane and ethanol were used for PFE of pistachio oil. The extraction yield was about one-third (i.e. 18 g/100 g) when ethanol was used as solvent.     

Soybean isoflavones: Efficacy of extraction conditions and effect of food type on extractability

Soy isoflavones are phytochemicals of intense interest due to their association with a variety of health protective effects. Analytical techniques to identify and quantify these compounds vary in accuracy, reproducibility and sensitivity. In this study, solvent extraction efficiencies, and the effect of replicate extractions, and sonication on the isoflavone content of two soy products (high and low protein content) were evaluated. The later study was conducted to determine the effect of protein content on isoflavone extractability. Repeated extractions (up to five sequential extractions) of soy meal sample increased the total concentration of isoflavones by 74%, 69% and 65%, using acetonitrile–HCl, methanol and ethanol. The increment for soy protein isolate was 147%, 103% and 105%, respectively. Sonication of both samples in the three solvents for 15 min extracted as much isoflavones as the total of the five sequential extractions. These results strongly indicates that, a one step extraction without sonication can markedly under-estimate the concentration of isoflavones in foods, and that protein content of foods may have a marked impact on isoflavone extractability.     

微波辅助法从大豆废料中提取分离大豆皂苷的实验研究

以大豆废渣为原料,大豆皂苷产率为评价指标,进行了微波辐射下提取大豆皂苷的工艺条件研究,考察了微波功率、萃取溶剂种类、溶剂浓度、料液比、提取时间和提取级数等对大豆皂苷产率的影响,并在单因素考察基础上,通过正交实验设计得出优化工艺条件。结果表明:在微波功率270W、提取时间90s、乙醇浓度75%、料液比为1∶10的条件下得到最优工艺条件。与传统的溶剂浸提法、索氏提取法相比较,微波辅助提取具有提取时间短、效率高、节约能源、产品质量高、原料利用率高、无污染等优点,并且明显提高了大豆皂苷的含量。     

超声辅助低共熔溶剂提取花生红衣中白藜芦醇的研究

采用低共熔溶剂,以超声辅助提取花生红衣中的白藜芦醇。通过对低共熔溶剂的筛选,氯化胆碱/乙二醇(摩尔比1∶2)具有较好的提取效果。在氯化胆碱/乙二醇为提取溶剂、加水量(以体积比计)为40%、超声温度为60℃、超声时间为60 min、料液比为1∶15(g/mL)的条件下,白藜芦醇的提取量为(5.16±0.07)μg/g。     

从豆渣中提取水溶性大豆多糖的工艺优化研究

以豆渣为原料采用水热法提取大豆多糖,对固液比、温度、pH值、提取时间进行单因素试验,分析了各因素对粗多糖产率、还原糖含量、透明度、水溶性大豆多糖纯度的影响。采用4因素3水平正交试验对工艺进行优化,得到了优化的工艺条件。根据综合评分,选出最佳参数是：固液比1∶20（g∶mL）,温度110 ℃,pH 4.5,提取时间3 h,所得粗多糖产率52.4%,还原糖含量3.86%,透明度86.14%,多糖纯度69.88%。     

Comparison of extraction solvents and conditions for herbicide residues in milled rice with liquid chromatography-diode array detection analysis (LC-DAD)

Different extraction procedures and clean-up methods were compared in order to develop a sample preparation procedure for the multi-residue analysis of six post-emergence herbicides (metsulfuron methyl, bensulfuron methyl, pyrazosulfuron ethyl, bentazone, bispyribac sodium and cyhalofop butyl) in rice grains followed by liquid chromatography-diode array detection (LC-DAD). Optimum results were obtained dispersing milled rice grain in water, followed by the addition of 1% acetic acid in acetonitrile, MgSO₄ and sodium acetate as a modification of the quick, easy, cheap, effective, rugged and safe (QuEChERS) method but no primary and secondary amine (PSA) sorbent was added due to the acidic nature of the herbicides. The method was further expanded to other post-emergence herbicides (quinclorac, clomazone and propanil). Except for quinclorac, which cannot be analysed with this method, the recoveries of the other eight herbicides were in the range 73–111%, with relative standard deviations lower than 12%. Limits of detection (LODs) ranged from 0.03 to 0.08 mg kg^?1. A single analyst can extract twelve samples in 4 h. The method presented here allows the simultaneous residue determination of the most common post-emergence herbicides employed in cultivating rice. It is simple, rapid, sensitive, and can be applied routinely to polished rice grain herbicide residue analysis.     

An effective and green method for the extraction and purification of aglycone isoflavones from soybean

In this paper, an effective and green strategy was developed to obtain aglycone isoflavones from soybean through the extraction, hydrolysis, and purification steps. Firstly, a novel ethanol-alkaline extraction method was designed and optimized. The high extraction yield (94.34%) of isoflavones was achieved under the optimal extraction conditions of pH 9.0, 70°C, 60 min, ethanol concentration of 65%, and 1:15 of the solid to liquid ratio. Then, the cellulase (GC-220) was used instead of traditional β-glucosidase to hydrolyze the glycoside isoflavones into aglycone isoflavones which gave an excellent conversion of 95%. Finally, the crude aglycone isoflavones have been purified by an environmental-friendly procedure comprised of ethanol precipitation, ethyl acetate extraction, and water rinse. The final amount of aglycone isoflavones obtained was 1.279 mg for every gram of defatted soybean by this strategy, and the final recovery, and purity of aglycone isoflavones could achieve 80.38 and 87.21%, respectively.     

A comparative study on phenolic profiles and antioxidant activities of legumes as affected by extraction solvents

ABSTRACT:  The objective of this study was to investigate how 6 commonly used solvent systems affected the yields of phenolic substances and the antioxidant capacity of extracts from 8 major classes of food legumes. Several antioxidant-related phytochemical compositions, namely, total phenolic content (TPC), total flavonoids content (TFC), and condensed tannins content (CTC), were investigated. In addition, antioxidant activities were tested using 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging, ferric-reducing antioxidant power (FRAP), and the oxygen radical absorbance capacity (ORAC). The results showed that the 50% acetone extracts exhibited the highest TPC for yellow pea, green pea, chickpea, and yellow soybean. Acidic 70% acetone (+0.5% acetic acid) extracts exhibited the highest TPC, TFC, and FRAP values for black bean, lentil, black soybean, and red kidney bean. The 80% acetone extracts exhibited the highest TFC, CTC, and DPPH-free radical scavenging activity for yellow pea, green pea, chickpea, and yellow soybean. The 70% ethanol extracts exhibited the greatest ORAC value for all selected legumes. These results indicated that solvents with different polarity had significant effects on total phenolic contents, extracted components, and antioxidant activities. High correlations between phenolic compositions and antioxidant activities of legume extracts were observed. The information is of interest to the nutraceutical food/ingredient industries since legumes are a rich source of antioxidants.     

混合溶剂动态浸提小麦胚芽黄酮、V_E营养油的研究

研究了混合溶剂浸提富含黄酮、VE的麦胚油。对正己烷、正己烷/乙酸乙酯、正己烷/正丁醇、正己烷/丙酮、甲醇/丙酮、异丙醇/1,2-二氯乙烷6种浸出溶剂进行筛选,发现正己烷/丙酮浸出效果较理想。兼顾提油效率、所提麦胚油的VE含量和黄酮含量,采用单因素实验和正交实验得出正己烷/丙酮浸出麦胚油的理想工艺条件为:浸出温度45℃,浸出溶剂滴速5.5 mL/min(原料100g),浸出时间45 min。该条件下,脱脂麦胚残油率0.354%,麦胚油VE含量3.794 9 g/kg,黄酮含量10.29 g/kg。     

溶剂法提取豆渣中活性成分的动力学研究

采用有机溶剂提取技术研究大豆豆渣中有效成分大豆异黄酮提取过程的动力学机理。以Fick扩散第一定律为基础,建立提取过程的动力学方程,实验结果表明,在50～75℃从豆渣中提取大豆异黄酮,其lnC与lnt呈线性关系,符合一级动力学方程特征,实验数据和动力学方程符合良好,从而为大豆豆渣的综合利用以及活性成分的提取提供有价值的理论依据。     

高效液相色谱法定量检测玉米油中玉米赤霉烯酮的溶剂萃取预处理方法研究

研究了高效液相色谱法(HPLC)定量检测精炼玉米油中玉米赤霉烯酮(ZEN)的溶剂萃取预处理方法,优化了溶剂萃取预处理条件并进行了方法的评估。结果表明:溶剂萃取预处理的最优条件为乙腈-水(体积比9∶1)混合溶液萃取、料液比1∶4、超声萃取时间20 min,该萃取预处理条件可实现ZEN准确定量测定,检出限达4.5μg/kg;10、100、1 000μg/m L加标水平下的加标回收率分别为77.9%、105.7%、95.0%,相对标准偏差2.05%~8.43%,优于传统免疫亲和柱净化预处理方法。