A systematic approach for extraction of phenolic compounds using parsley (Petroselinum crispum) flakes as a model substrate

The impact of extraction methodology and polarity of extraction solvents on the assay of phenolic compounds was investigated using parsley (Petroselinum crispum) flakes as a model substrate. This systematic study was undertaken to address substantial variations in the extraction procedures, solvents and conditions as described in the recent literature. Five different extraction procedures [shaking, vortex mixing, sonication, stirring and pressurized liquid extraction (PLE)] and three different solvents (methanol, ethanol and acetone), with five different solvent to water ratios per solvent, were used for extraction. Extracts were analyzed for phenolic content by high‐performance liquid chromatography and Folin–Ciocalteu assays. The yields of phenolic compounds extracted with a pressurized liquid extractor were comparable to or better than those of four classical extraction procedures. Optimum extraction efficiency with PLE was obtained when extractions were performed with four extraction cycles using ethanol–water (50:50, v/v). The amount of apiin (4,5,7‐trihydroxyflavone 7‐apiosylglucoside) and malonylapiin (apigenin malonylapiosylglucoside) isolated from parsley varied with the composition of extraction solvent. Apiin extractability was found to be a maximum when the solvent (ethanol, methanol or acetone) to water ratio was 30:70 (v/v), whereas higher amounts of malonylapiin were isolated with a reverse solvent to water ratio (70:30, v/v). Malonylapiin was not detected when parsley samples were extracted with organic solvent to water ratios of 10:90 (v/v) and 30:70 (v/v). Published in 2006 by John Wiley & Sons, Ltd     

发酵豆粕中大豆异黄酮的超声波提取工艺

为提高大豆异黄酮的提取率，以发酵豆粕为原料，采用超声波提取技术，通过单因素实验及正交实验对大豆异黄酮提取工艺中提取溶剂、料液比、时间、次数等因素进行探讨。结果表明：采用80％乙醇为提取剂，料液比1g：15ml，提取时间20min，提取2次，大豆异黄酮提取率最高，可达到0．548％。超声波提取发酵豆粕中大豆异黄酮是一种较为理想的方法。     

大豆异黄酮纯化工艺研究

以大豆为原料,乙醇为溶剂,提取大豆异黄酮,探讨大豆异黄酮提取物纯化工艺,以寻求大豆异黄酮纯化最佳工艺方法。先将大豆异黄酮粗提物进行脱脂、脱蛋白初步处理,再结合大孔树脂吸附与乙酸乙酯萃取精制,最后冷冻结晶得到产品。结果表明:大孔树脂吸附与解吸最佳工艺条件为:上样液浓度0.15 mg/mL,上样pH值为4.5～5.5,上样量为4.5BV,吸附流速为1.5ml/min,静态吸附5h,解吸剂80%乙醇,解吸流速0.5ml/min,并以三波长紫外分光光度法分析检测,得到大豆异黄酮产品纯度可达82.5%。     

Improved functionality of soft soybean curd containing Monascus fermented soybean ethanol extract

Monascus fermented soybeans (MFS) were produced by solid state fermentation and ethanol extractions were carried out to recover monacolin K (MK) and isoflavones from the MFS. About 99 and 87% of monacolin K (891 mg/kg) and isoflavones (895 mg/kg) were recovered by 80%(v/v) ethanol extraction. The 80% ethanol extract also showed significantly higher antioxidant activities (DPPH, ABTS radical scavenging activity, and ferric reducing antioxidant power) than the other ethanol extracts prepared by either 40 or 60% ethanol. The 80% Monascus fermented soybeans extract (MFSE) also contained significant α-glucosidase inhibitory activity (2.7 acarbose g equivalents/g MFS). Based on the results, MFSE can be used to enrich bioactive MK and isoflavone aglycones in soft soybean curd products.     

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。     

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.     

Pressurized solvent extraction of wheat germ oil

This study examined the pressurized solvent extraction of wheat germ oil. The effects of temperature (45–135 °C at 1500 psi), extraction time, sample size and solvent type on the extraction efficiency and oil quality were studied. Extraction efficiency of the normal-hexane was compared to that of the iso- and high purity-hexane, iso-propanol, ethanol and acetone. The extracts were analyzed for n-3 and n-6 polyunsaturated fatty acid content. Pressurized solvent extraction reduced extraction time significantly as compared to Soxhlet extraction. The time required for complete oil recovery was dependent on the amount of wheat germ used for extraction. The amount of extract collected was highest when ethanol was used as a solvent for pressurized solvent extraction. Soxhlet and pressurized solvent extractions resulted in similar oil yields when hexane was used as a solvent. Fatty acid composition of the extracts was not affected by either temperature or extraction method. The experimental results indicate that a pressurized solvent extraction technique reduces solvent consumption and extraction time with no adverse effect on the extraction yield and fatty acid composition of the oil.     

Antioxidant Activity of Pink-Flesh Guava (Psidium guajava L.): Effect of Extraction Techniques and Solvents

The effect of commonly used techniques and solvents in the antioxidant activities of pink-flesh guava fruit were studied. The extraction techniques compared were homogenization, shaking, sonication, magnetic stirring, and maceration for 1, 2, and 3 days. The solvent systems used were methanol, ethanol, and acetone at three different concentrations (50%, 70%, and 100%) and with 100% distilled water. The antioxidant activity of the fruit was evaluated using Folin–Ciocalteu index, ferric-reducing antioxidant power assay, and 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging capacity. Ultrasonic and homogenization were the best techniques to extract the antioxidant from guava fruit. Homogenization technique was found to be the most convenient exhaustive and time-saving extraction technique. Results showed that the extracting solvent significantly (P < 0.05) altered the antioxidant property estimations of pink-flesh guava fruit. Pure solvents were inefficient extraction media for antioxidant. Enhanced extraction yields were obtained from solvent containing higher water concentrations and 50% acetone is a recommended solvent for extracting antioxidants compounds from pink-flesh guava fruit. High correlations between phenolic compositions and antioxidant activities of pink-flesh guava extracts were observed. High levels of antioxidant activities were detected in pink-flesh guava, indicating that the fruit may serve as an excellent dietary source of natural antioxidants.     

A Pilot-Plant Study of Continuous Ultrasonic Extraction of Soybean Protein

Methods were studied to extract soybean proteins from commercial defatted flakes with ultrasonic energy, continuously and efficiently, in a pilot plant. Studies also included batchwise sonication of aqueous soybean slurries in a tank. Parameters investigated included soybean-to-solvent ratios of 1:10, 1:20, and 1:30; solvents of tap water and 0.1N NaOH; and extraction with and without sonication. Protein yield and energy requirements for extraction were measured to correlate the operating condition with the extent of protein extraction. For a residence time of 0.7 sec in the continuous sonication process, the extracted protein yield was greatest at 1:30 soy-to-alkaline solvent ratio. Energy input to produce protein isolate is the least at 1:10 soy-to-alkaline solvent. Although the continuous sonication procedure is workable, the commercial operation remains to be tested.     

Effects of Solvent, Temperature, Time, Solvent-to-Sample Ratio, Sample Size, and Defatting on the Extraction of Soluble Sugars in Soybean

ABSTRACT Extraction solvent, temperature, time, and solvent‐to‐sample ratio were studied to identify the optimal conditions for extracting sugars from nondefatted soybean. Water and 10%, 50%, and 80% (v/v) ethanol were used as the solvents. Extraction temperatures of 25 °C, 50 °C, and 80 °C, for 15, 30, and 60 min and solvent‐to‐sample ratios of 5:1, 10:1, and 15:1 (v/w) were combined with different solvents. The sugar composition in the soybean extracts was analyzed by high‐performance anion‐exchange chromatography with pulsed amperometric detection. The sugar appropriate to be used as the standard in the phenol‐sulfuric acid method in sugar quantification, and effects of sample size and defatting on sugar extraction were also evaluated. The optimum extraction protocol concluded from this study includes the use of water as the solvent at a solvent‐to‐sample ratio of 5:1 at 25 °C or 50 °C for 15 min. Sucrose was shown to be the best sugar as the standard to quantify the total soluble sugars in soybean. Extractions from sample size of 1 g and 0.1 g yielded similar soluble sugars. A greater amount of sugars was extracted with the defatted soybean meal than with the nondefatted sample.     

大豆豆脐中异黄酮的提取工艺优化

为了提高大豆豆脐在大豆加工行业的利用率以及更大程度地发挥大豆豆脐的营养价值,本文在国标大豆异黄酮检测方法的基础上,建立了一套适用于测定大豆豆脐中异黄酮含量的高效液相色谱方法。本实验以大豆豆脐为原料,采用乙醇-水溶液作为提取溶剂,通过单因素实验和正交实验确定超声波辅助提取大豆异黄酮的最佳工艺,结果表明:各因素对大豆异黄酮提取率影响大小的顺序为:提取温度(B)>提取时间(C)>料液比(D)>乙醇浓度(A);在乙醇浓度为80%、提取温度为80℃、提取时间为1.5h、料液比为1:35 g/mL时提取三次,大豆异黄酮的提取率可达10.88±0.120 mg/g。本方法准确、高效,能够提取出原料中90%以上的大豆异黄酮,该提取工艺稳定可行,可为大豆豆脐中异黄酮的提取提供理论依据。     

大豆异黄酮及其苷元的研究进展

大豆异黄酮是一种天然的雌激素,是大豆生长过程中的次级代谢产物,其主要位于大豆种子的子叶和胚轴中。其中97%左右以糖苷形式存在,其余以苷元形式存在,大豆异黄酮苷元是其发挥主要功能活性的形式。目前大豆异黄酮的常规提取方法包括有机溶剂萃取法、超声波辅助提取法、微波辅助提取法、超临界流体萃取法、亚临界水法等。研究表明,大豆异黄酮及其苷元具有一定的生理功效,包括预防心血管疾病,预防骨质疏松,抗肿瘤和神经保护等。本文在介绍大豆异黄酮及其苷元的组成、化学结构特性的基础上,详细综述了大豆异黄酮及其苷元的研究概况、提取工艺和主要功能活性,并展望了该领域今后的发展趋势和有待加强的研究方向,旨在为大豆异黄酮及其苷元产业化开发和深入研究其临床应用价值提供参考依据。     

Comparison between ultra-homogenisation and ultrasound for extraction of phenolic compounds from teff (Eragrostis tef (Zucc.))

This study investigated the effect of the solvent composition on the extraction of phenolic compounds from teff grains and compared the efficiency between the techniques homogeniser-assisted extraction (HAE) and ultrasound-assisted extraction (UAE). The solvents used were water, ethanol and methanol, and the response analysed was the total phenolic content (TPC). The quantitative profile of polyphenols extracted was also determined by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-TQD). According to the optimisation, the maximum response was estimated at solvent ratios of 51:40:9 and 49:26:25 (water/ethanol/methanol, v/v/v) for HAE and UAE, respectively. Under optimal conditions, the extraction technique did not significantly influence the TPC extracted, but the TFC (total flavonoid content) and the antioxidant capacity were significantly higher when UAE was used. The phenolic acids p-coumaric and protocatechuic and the flavonoids quercetin, rutin and myricetin were the main polyphenols extracted. Both techniques studied were efficient in extracting polyphenols from whole teff grains.     

豆粕中大豆总异黄酮的提取工艺优化

主要研究豆粕中大豆总异黄酮的醇提工艺,并用HPLC法测定大豆总异黄酮含量。以大豆总异黄酮为提取目的,并通过对各单因素的考察和正交试验对工艺进行优化。结果表明,大豆异黄酮醇提工艺的最佳条件为:乙醇浓度70%,料液比1∶15(mg/mL),提取温度80℃,提取4 h,分2次提取,第1次提取时间为3 h,第2次提取1 h,总提取量是16.11 mg/g。     

Sequential high pressure extractions applied to recover piceatannol and scirpusin B from passion fruit bagasse

Passion fruit seeds are currently discarded on the pulp processing but are known for their high piceatannol and scirpusin B contents. Using pressurized liquid extraction (PLE), these highly valuable phenolic compounds were efficiently extracted from defatted passion fruit bagasse (DPFB). PLE was performed using mixtures of ethanol and water (50 to 100% ethanol, w/w) as solvent, temperatures from 50 to 70 °C and pressure at 10 MPa. The extraction methods were compared in terms of the global yield, total phenolic content (TPC), piceatannol content and the antioxidant capacity of the extracts. The DPFB extracts were also compared with those from non-defatted passion fruit bagasse (nDPFB). Identification and quantification of piceatannol were performed using UHPLC–MS/MS. The results showed that high TPC and piceatannol content were achieved for the extracts obtained from DPFB through PLE at 70 °C and using 50 and 75% ethanol as the solvent. The best PLE conditions for TPC (70 °C, 75% ethanol) resulted in 55.237 mg GAE/g dried and defatted bagasse, whereas PLE at 70 °C and 50% ethanol achieved 18.590 mg of piceatannol/g dried and defatted bagasse, and such yields were significantly higher than those obtained using conventional extraction techniques. The antioxidant capacity assays showed high correlation with the TPC (r > 0.886) and piceatannol (r > 0.772). The passion fruit bagasse has therefore proved to be a rich source of piceatannol and PLE showed high efficiency to recover phenolic compounds from defatted passion fruit bagasse.     

Protein valorization from ora-pro-nobis leaves by compressed fluids biorefinery extractions

Ora-pro-nobis (Pereskia aculeata) leaves were selected as raw material for biorefinery application based on compressed fluid extractions with green solvents. The fractionation followed the sequential processes: (1) Supercritical fluid extraction (SFE) with CO₂, (2) Gas expanded liquid extraction (GXL), using CO₂:Ethanol, and pressurized liquid extraction (PLE) with ethanol, and (3) Subcritical water extraction (SWE). In vitro analysis of total phenolic and total carotenoid contents and antioxidant activity (DPPH and ORAC) were assessed, stipulating PLE method as the second step of the sequential extractions. Total protein and carbohydrate contents were evaluated from SWE samples. Phenolics profile from PLE and SWE samples was assessed by LC-DAD-ESI-MS/MS, identifying 8 phenolic compounds, with quercetin, isorhamnetin and kaempferol as the main detected flavonoids. SWE at 150 and 185 °C provided the highest protein recovery, as the third step in a sequential process.     

低共熔溶剂提取桂花黄酮的工艺优化

为了探索一种高效、环保的桂花黄酮提取方法,本文设计并制备了6种低共熔溶剂,通过比较醇提、冻融、超声波及微波四种技术,确定了超声波辅助-低共熔溶剂的提取工艺。通过单因素试验考察液料比、摩尔比、含水量、超声功率以及超声时间对桂花黄酮提取量的影响。在单因素的基础上,采用响应面法对提取工艺进一步优化。结果表明：桂花黄酮最优提取工艺为超声波辅助-三元低共熔溶剂提取（氯化胆碱/山梨醇/1,2-丙二醇）;最佳工艺条件为：液料比60:1 (mL/g),氯化胆碱:山梨醇:1,2-丙二醇=2:1:4,含水量62 mol,超声波功率150 W,超声时间16 min,在此条件下提取量达到了10.06 mg/g,比传统醇提法提高了8.93 mg/g,证实超声波辅助-绿色低共熔溶剂技术提取桂花黄酮的高效性。实验结果与响应面模型预测值接近,证实模型的有效性。本研究为低共熔溶剂在天然产物绿色提取方面的应用提供参考。     

Isolation of the sweet components from Siraitia grosvenorii

Powdered concentrate from dried Luo Han Guo fruit was subjected to liquid extraction by Soxhlet (hexane:ethanol, 1/4 v/v) or with subcritical water (scH₂O) or with supercritical ethanol carbon dioxide (scCO₂). Whereas exhaustive Soxhlet extraction of the crude dried fruit powder (CDFP) was inefficient, pressurized water extraction in the presence of chromatographic support (Alumina, Celite or Silica gel) was beneficial to the scH₂O recovery of mogrosides as determined by colourimetry. With a flow rate of 0.7 mL min⁻¹ scH₂O and a back pressure of 11.7 MPa, a maximum recovery was obtained at 150 °C; yet increases in recovery for extractions beyond 10 min were marginal. The recovery of target compounds were very inefficient for scCO₂ alone but was improved with the addition of 0.3 mL min⁻¹ ethanol as co-solvent to the mobile phase and by adding chromatographic support to the substrate. Increased pressure during the scCO₂ extractions were beneficial to the recoveries that were maximized at 60 °C. However, increases in the recoveries of mogrosides for extractions beyond 90 min for the dried fruit powder or beyond 30 min for the partially purified concentrate were very modest. Of the three extraction techniques, Soxhlet, scCO₂ or scH₂O, the latter technique, in tandem with ultra-sonication of the dried fruit powder proved to be very efficient so that there was little value to partially purifying this substrate prior to pressurized fluid extraction.     

High-power ultrasonication-assisted extraction of soybean isoflavones and effect of toasting

The effect of high-power ultrasonication (HPU) on extraction of soybean isoflavones and components, including total phenolic and DPPH radical scavenging activities (RSA) were evaluated. Isoflavones from defatted soybean flakes were extracted using a bench scale HPU system at 20 kHz and varying amplitudes (18–54 μm) for 1 and 3 min. Aqueous acetonitrile, and aqueous ethanol based solvents were evaluated for extraction at samples-to-solvent ratios of 0.1:1 and 0.2:1. The non-sonication control extraction was with mixing with magnetic stirrer for 2 h. Preliminary data indicated 1.2–1.5 times more genistein recovery at 1, and 3 min sonication compared to control, however, total phenolic decreased. The genistein recovery was lower at higher sonication levels. RSA also decreased to 40% for HPU-assisted extractions. Total isoflavones recovery in HPU-assisted extractions increased from 600 to 5813 μg/g. The concentration of major isoflavone components, genistein, daidzein, and glycitein also increased by 10-fold. HPU for 3 min reduced the average particle size of treated soy flakes from 530 μm to 60 μm. Toasting at 150 °C of defatted soy flake for longer period of time led to higher aglycone concentration in extract; however, 2 h toasting was sufficient prior to HPU-assisted extraction.     

Microwave‐assisted extraction of secoisolariciresinol diglucoside from flaxseed hull

Microwave‐assisted extraction (MAE) of secoisolariciresinol diglucoside (SDG) from defatted flaxseed hull (DFH) was studied. The effects of pre‐soaking methods and extraction parameters (ethanol concentration (0–100%, v/v), microwave energy input (50–390 W), liquid to solid ratio (5:1 to 40:1, mL g^?1) and irradiation time (10–330 s)) on the SDG yield were investigated. Response surface methodology (RSM) was applied to optimise the MAE conditions as irradiation time 90.5 s, ethanol concentration 40.9% (v/v), liquid to solid ratio 21.9:1 (mL g^?1) and microwave power 130 W. The SDG recovery from DFH with MAE was 11.7 g SECO kg^?1 DFH (on dry‐weight basis), which was significantly higher than that of stirring extraction (10.0 g SECO kg^?1 DFH) and Soxhlet extraction (7.60 g SECO kg^?1 DFH). Compared with stirring extraction and Soxhlet extraction, MAE showed its superiority in improving SDG yield and saving time and energy. Copyright © 2007 Society of Chemical Industry