油茶蒲总多酚回流提取工艺的研究

乙醇回流提取油茶蒲中的总多酚,考察了提取温度、提取时间、乙醇浓度和液料比对油茶蒲总多酚的提取效果的影响。结果表明,各因素对油茶蒲总多酚的提取效果的影响大小依次为:提取温度液料比乙醇浓度提取时间;油茶蒲总多酚的适宜提取工艺条件为:以50%的乙醇溶液为提取溶剂,液料比为20 mL/g,在70℃温度下回流提取3次,每次80 min。在此工艺条件下,总多酚提取量为71.13 mg/g。     

微波预处理-溶剂回流提取马占相思叶多酚的工艺研究

研究微波预处理-溶剂回流提取马占相思叶多酚的工艺条件。以干马占相思叶粉为原料,用正交实验法对马占相思叶总多酚的微波预处理提取工艺进行优选,考察预处理乙醇浓度、固液比、微波处理时间对马占相思叶总多酚提取量的影响。结果表明,微波预处理溶剂回流提取马占相思树叶总多酚的最佳工艺参数为:润湿乙醇浓度为50%,用量为样品量的2倍,在微波功率800 W条件下处理30 s后,用体积分数70%乙醇在料液比1∶7,水浴温度70℃、自然pH值(pH=6.38)浸提条件下回流提取30 min。在此工艺条件下,可提取总多酚18.013 mg/g马占相思树叶,所得的多酚提取物以总多酚计的清除DPPH自由基的IC50值为39.126 g DPPH/g总多酚。     

沙果多酚的提取及组成分析

采用水浴振荡辅助乙醇提取法提取沙果果干中的总多酚,对提取工艺进行优化并分析了沙果果干中的多酚种类。通过正交试验优化出沙果青果的最佳提取工艺:乙醇体积分数50%,料液比1∶25(g∶mL),水浴振荡时间50 min,水浴振荡温度30℃,此条件下多酚得率可达(7.875±0.008)mg/g;沙果熟果的最佳提取工艺:乙醇体积分数60%,料液比1∶25(g∶mL),水浴振荡时间30 min,水浴振荡温度40℃,此条件下多酚得率可达(10.259±0.020)mg/g。液相色谱分析表明:沙果青果多酚主要含有4种多酚,分别为绿原酸22.033%、原花青素B_(2)8.875%、表儿茶素5.95%和根皮苷1.259%,这4种多酚占总多酚的38.117%;沙果熟果除含有上述4种多酚(分别为41.0758%、5.6413%、8.3252%、0.4998%),还含有(+)-儿茶素(7.2444%),这5种多酚占总多酚的62.7865%,沙果中仍有大部分未知多酚未检出。沙果熟果多酚种类及含量高于青果,营养价值更丰富。     

香蕉皮多酚的提取工艺研究

以香蕉皮为材料,乙醇溶液为溶剂,考察乙醇浓度、浸提温度、浸提时间和料液比对香蕉皮多酚提取效果的影响,利用正交实验对多酚的提取工艺进行优化。结果表明,影响多酚提取效果的主次因素顺序为:乙醇浓度提取温度提取时间料液比。最佳工艺条件为:提取溶剂为80%乙醇、料液比1∶4(g/mL)、提取温度为80℃、提取时间120 min,在此条件下,多酚提取率为1.46%。     

马占相思树叶总多酚的微波提取工艺研究

研究微波提取马占相思叶中总多酚的工艺条件,以总多酚提取量为参考指标,考察乙醇浓度、固液比、微波提取时间、提取温度对马占相思叶总多酚提取量的影响。得到的最佳工艺条件为:20 g原料,以料液比1∶10加入50%的乙醇溶液,在80℃下每次微波提取35 min,提取3~4次。在此条件下,每克马占相思叶可提取总多酚36.368 1~43.414 7 mg。     

Study on the microwave-assisted extraction of polyphenols from tea

This study demonstrated a promising method for quickly extracting tea polyphenol (TP) by microwave-assisted extraction (MAE) technology. Some influential parameters, including MAE temperature, microwave power, concentration of extraction solvent, MAE time and the solid/liquid ratio, were investigated. The optimum condition of MAE was obtained by dual extraction with 60% ethanol (v/v) and the solid/liquid ratio 1:12 g/mL at 80°C for 10 minutes under the microwave power 600W. The yield of TP was 96.5% under the described condition. Compared with traditional methods, including hot reflux extraction (HRE), ultrasound-assisted extraction (UAE) and supercritical fluid extraction (SFE), the extraction time was saved 8 times than that of HRE, and the yield was increased by 17.5%. The extraction time at comparable levels of production was saved 2 times, and the energy consumption was one fourth that of UAE. The extraction time was saved 5 times than that of SFE, and the yield of TP was increased by 40%. Moreover, compared with MAE of TP studied by others, it decreased the solid/liquid ratio from 1: 20 to 1: 12 g/mL without 90-min pre-leaching time, and the yield of TP was increased by 6%–40%.     

Study on the microwave-assisted extraction of polyphenols from tea

This study demonstrated a promising method for quickly extracting tea polyphenol (TP) by microwave-assisted extraction (MAE) technology. Some influential parameters, including MAE temperature, microwave power, concentration of extraction solvent, MAE time and the solid/liquid ratio, were investigated. The optimum condition of MAE was obtained by dual extraction with 60% ethanol (v/v) and the solid/liquid ratio 1:12 g/mL at 80°C for 10 minutes under the microwave power 600 W. The yield of TP was 96.5% under the described condition. Compared with traditional methods, including hot reflux extraction (HRE), ultrasound-assisted extraction (UAE) and supercritical fluid extraction (SFE), the extraction time was saved 8 times than that of HRE, and the yield was increased by 17.5%. The extraction time at comparable levels of production was saved 2 times, and the energy consumption was one fourth that of UAE. The extraction time was saved 5 times than that of SFE, and the yield of TP was increased by 40%. Moreover, compared with MAE of TP studied by others, it decreased the solid/liquid ratio from 1 ∶ 20 to 1 ∶ 12 g/mL without 90-min pre-leaching time, and the yield of TP was increased by 6%–40%.     

乙醇提取-丙酮沉淀法提取分离茶皂素的工艺研究

以油茶饼粕为原料,采用乙醇提取-丙酮沉淀法对茶皂素进行提取分离。以茶皂素纯度和得率为考察指标,对乙醇体积分数、液料比、提取温度、提取时间、提取次数、提取液浓缩程度和丙酮用量等工艺参数进行了单因素优化。结果表明：体积分数95%的乙醇为提取溶剂,乙醇与预处理过的油茶饼粕液料比为9：1（mL：g）,提取温度为70℃,提取时间为4 h,提取次数为2次,提取液浓缩至刚好有固体析出,丙酮用量为4倍浓缩液体积量时提取分离效果较佳,得到的茶皂素纯度为85.17%,得率为9.82%。不同溶剂打浆对产品纯化效果的比较发现：丙酮、乙酸乙酯、无水乙醇、体积分数95%的乙醇作为打浆纯化溶剂用于提高茶皂素纯度效果均不明显。     

酶解法提取虎杖中白藜芦醇、白藜芦醇苷、大黄素

用纤维素酶对虎杖进行了酶解,提高了虎杖中白藜芦醇的提取率,同时提取出白藜芦醇苷和大黄素。通过单因素实验考察了酶解温度、pH、酶解时间、酶用量对目标物提取率的影响,得出较佳的酶解工艺条件为:酶用量2mg/g虎杖,pH=3.0,在40℃酶解1h。酶解后用m(虎杖):m[φ(乙醇)=60%]=1:20,50℃提取2h。w(白藜芦醇)=1.50%,w(白藜芦醇苷)=0.38%,w(大黄素)=0.78%。酶解法较直接提取法更有利于虎杖中有效成分白藜芦醇、大黄素的提取。     

均匀试验设计法提取米糠中阿魏酸工艺优化

使用碱醇提取法从米糠中提取阿魏酸,采用HPLC法检测阿魏酸的含量。设计均匀试验,考察了阿魏酸的提取率与氢氧化钠浓度、提取温度、提取时间、氢氧化钠与乙醇比、固液比的关系,实验表明,阿魏酸最佳提取条件为:用1.3%的氢氧化钠溶液与乙醇按5.6∶1的比例混和,83.2℃下提取2.8 h,固液比为1∶9.4,提取液中加入0.2 g/L的亚硫酸钠溶液作为抗氧化剂,最大提取率为514 mg/100g。     

Extraction optimization and adsorption isotherm kinetics of polyphenols from blossoms of Citrus aurantium L. var. amara Engl

ABSTRACT

Crude extracts were extracted from blossoms of Citrus aurantium L. var. amara Engl. with 50% ethanol (CAVAP-E), 50% methanol (CAVAP-M), and hot water (CAVAP-W). CAVAP-W had the highest polyphenol yield of 3.7%. The optimum values of liquid/solid ratio, ultrasonic time, and ultrasonic power were 34.06 mL/g, 1 h, and 81.04 W, respectively. The adsorption characteristics of polyphenols were investigated using different macroporous resins. AB-8 and HP-20 resins offered higher adsorption and desorption capacities. Langmuir equation was more suitable to predict the adsorption of polyphenols. The pseudo second-order model was satisfactory to describe the kinetic data of polyphenols onto AB-8 and HP-20.     

In vitro interaction of polyphenols of coffee pulp and some proteins

The in vitro interaction of pure polyphenols and polyphenol extracts of coffee pulp with pure proteins was studied. The polyphenols used for the assays were tannic acid, chlorogenic acid and catechin, and the proteins were gelatin, casein and bovine serum albumin (BSA). Different pHs and different polyphenol/protein ratios were used in the experiments. Extracts of coffee pulp in methanol, methanol-water (50:50), ammonium hydroxide 3%, and calcium hydroxide 1%, were used. In general, the maximum binding of polyphenol with protein was obtained at a polyphenol/protein ratio of 1/2, at a pH of 5.0. The higher binding percentages were found with the ammonium hydroxide extract and with tannic acid. The lowest binding percentage was obtained with the methanol-water extract. The other extracts presented intermediate binding degrees. The results herein reported demonstrate that the polyphenols of coffee pulp have capacity to bind proteins in vitro at the pHs assayed. This phenomenon may be the cause of the deficient protein utilization when coffee pulp is included in the animals' diet.     

超声场辅助生物酶法提取苦楝素的研究

采用超声场辅助生物酶法提取苦楝素,研究了生物酶浓度、超声场频率、酶解时间、超声场功率、酶解液pH值、提取温度、液固比对苦楝素提取率的影响。获得的优化条件为:生物酶浓度0.1 mg/mL,酶解时间2 h,超声场频率40 kHz,功率120 W,酶解液pH值5.0,提取温度40℃,液固比25 mL/g。优化条件下,苦楝素的提取率达3.363%。     

响应面优化淫羊藿抗氧化多酚超声提取工艺

以总多酚得率和DPPH自由基清除率为指标,采用响应面设计法优化淫羊藿抗氧化活性多酚超声提取工艺。结果表明以多酚得率为指标时,最佳工艺条件为：57％乙醇,料液比28 mL／g,在50℃下超声提取25 min,总多酚得率为34．58 mg／g;以DPPH自由基清除率为指标时,最佳工艺条件为：58％乙醇,料液比30 mL／g,在50℃下超声提取22 min, DPPH自由基清除率为88．4％。     

Optimization of the Extraction of Anthocyanins from the Fruit Skin of Rhodomyrtus tomentosa (Ait.) Hassk and Identification of Anthocyanins in the Extract Using High-Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (HPLC-ESI-MS)

Anthocyanins are naturally occurring polyphenols that impart bright color to fruits, vegetables and plants. In this study, the extraction of anthocyanins from freeze-dried fruit skin of downy rose-myrtle (Rhodomyrtus tomentosa (Ait.) Hassk var. Gangren) was optimized using response surface methodology (RSM). Using 60% ethanol containing 0.1% (v/v) hydrochloric acid as extraction solvent, the optimal conditions for maximum yields of anthocyanin (4.358 ± 0.045 mg/g) were 15.7:1 (v/w) liquid to solid ratio, 64.38 °C with a 116.88 min extraction time. The results showed good fits with the proposed model for the anthocyanin extraction (R(2) = 0.9944). Furthermore, the results of high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) analysis of the anthocyanins extracted from the fruit skin of downy rose-myrtle revealed the presence of five anthocyanin components, which were tentatively identified as delphinidin-3-glucoside, cyanidin-3-glucoside, peonidin-3-glucoside, petunidin-3-glucoside and malvidin-3-glucoside.     

Investigation of Oleuropein Content in Olive Leaf Extract Obtained by Supercritical Fluid Extraction and Soxhlet Methods

The separation processes of the phenolic compounds from solid plant matrixes are of great importance. In the scope of developing more efficient methods to separate olive leaf extract, dried and ground olive tree leaves from Aegean region of Turkey were extracted by means of Soxhlet and supercritical fluid extraction (SFE) methods. In the Soxhlet method, different types of solvents (hexane, water, ethanol, methanol, and methanol/hexane (3:2, v/v) mixture) were used to determine the effect of the solvent type on the extraction performance. In the SFE method, the effect of pressure (100–300 bar), temperature (50 and 100°C), and type of co-solvent on the amount of both extract and oleuropein were investigated. Ethanol, methanol and water were selected as co-solvent in 20% (v/v) amount. Quantitative analysis was performed by using a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) technique. The results of SFE were compared with those obtained by the Soxhlet method. Whereas the highest oleuropein yield was achieved via the Soxhlet method through methanol with the value of 37.84 mg/g dried leaf, the best oleuropein yield was achieved with the value of 14.26 mg/g dried leaf by using CO₂ modified by methanol at 300 bar and 100°C in the SFE method.     

Antioxidant activity of tea extracts in lipids and correlation with polyphenol content

The present study examined the antioxidative activity of water and ethanol extracts of green and black tea leaves against the oxidation of heated sunflower oil and lard. Oxidation was conducted at 110 °C in the Rancimat test. Total polyphenols and catechin contents in tea extracts were measured. The research showed that the total polyphenol content in green and black tea leaves was 205.2 and 148.7 mg/g, respectively. In tea leaves extracts, it ranged between 245.9 mg/g and 837.7 mg/g and depended on the extraction solvent and the kind of tea used (p <0.001). The highest polyphenol content was observed in samples extracted with 95% ethanol, lower contents were found with the use of water. Results showed that the highest antioxidant activity, measured as an induction period, with 1000 ppm green tea ethanol extract, was comparable to á‐tocopherol activity in sunflower oil. In lard, the longest induction period was measured with 500 and 1000 ppm of green tea ethanol extract. Other tea extract concentrations were significantly less active. Statistical analysis of the tea extract antioxidant activity in lipids in the Rancimat test showed an essential influence of the catechin contents. Further statistical analysis also showed an influence of (?)‐epicatechin gallate (ECG), (?)‐epicatechin (EC), and (+)‐catechin (C) contents in the tea extracts on the antioxidant activity in lipids. It was stated that the antioxidant activity was higher in tea extracts containing high levels of ECG, EC, and C.     

Extraction of Glycyrrhizic Acid and Glabridin from Licorice

The extraction and separation conditions of glycyrrhizic acid and glabridin from licorice were investigated. By changing the different extraction solvents, procedures, times and temperature, the optimum extraction condition was established: the used of ethanol/water (30:70, v/v) as an extraction solvent, and 60 min dipping time under 50°C. The extracts of licorice were separated and determined by reversed-phase high performance liquid chromatography with a methanol/water (70:30, v/v, containing 1% acetic acid) as the mobile phase. Under the optimum extraction condition, 2.39 mg/g of glycyrrhizic acid and 0.92 mg/g of glabridin were extracted from Chinese licorice and the recoveries were 89.7% and 72.5% respectively.     

陕北南瓜多糖的提取工艺研究

对陕北南瓜多糖热水提取和碱水提取的工艺参数进行了研究,考察了料液比、浸提时间、温度、pH值对南瓜多糖提取率的影响。结果表明,陕北南瓜多糖的最佳热水提取工艺为:提取温度65℃,料液比1∶40,提取时间2 h,提取率为43.21 mg/g;最优的碱水提取工艺为:提取温度60℃,料液比1∶50,提取时间2 h,pH值为13,提取率为57.72 mg/g。两种工艺路线成本低廉,工艺简单,能保证食品的安全性和提取物的天然活性。     

大孔吸附树脂纯化石榴皮多酚

从D3520、D4020、AB-8、D140、D141、D160、DM-301、DA-201、SAD-7和D101大孔吸附树脂中筛选出D141树脂,研究了其对石榴皮多酚的静态与动态吸附和解吸性能。结果表明,D141树脂对石榴皮多酚的饱和吸附量为19.86 mg/g(干树脂),吸附等温线符合Langmuir方程,饱和吸附时间为5 h,适宜解吸剂为体积分数70%的乙醇溶液;以质量浓度9 mg/mL的石榴皮提取液上柱,流速为1.8~2.0 BV/h时,树脂的多酚穿透吸附容量为39.42 mg/g(干树脂),2.5 BV体积分数70%的乙醇溶液可将吸附于柱上的石榴皮多酚完全洗脱。以该条件纯化石榴皮多酚提取物时,纯化样的收率为15.4 g/100 g(石榴皮),多酚质量分数从34%提高到76.34%。