绿咖啡豆中总绿原酸的纯化工艺研究

绿咖啡豆中的绿原酸共有九种同分异构体,所有同分异构体的总和称为总绿原酸,研究的主要目的是通过优化大孔吸附树脂纯化工艺将绿咖啡豆提取物中的总绿原酸含量由25%提高至70%以上,通过实验筛选合适的大孔吸附树脂,并优化树脂纯化的工艺参数如:上柱液浓度、上柱流速、解析溶剂度数、解析溶剂用量、解析流速等工艺指标,建立优化的纯化工艺路线。结果表明:上柱总绿原酸浓度为8mg/m L,上柱流速为1.0BV/h,解析用乙醇浓度为70%(v/v),乙醇用量为2BV,解析流速为1.5BV/h,经纯化后的总绿原酸经HPLC检测,总绿原酸含量可达71.23%,回收率可达87.46%。     

绿咖啡豆中绿原酸的分离纯化

对未烘焙绿咖啡豆中绿原酸的分离纯化进行深入研究.采用热水重复分批浸提法,在单因素实验基础上,采用Box-Behnken中心组合实验设计响应面分析法,获得了绿咖啡豆中绿原酸的最佳提取条件:温度79.8℃,溶剂pH值2.8,料液比1∶6,提取时间3.0 h,绿原酸的最大提取得率为92.0％.比较了多种不同规格的树脂对绿原酸的分离纯化效果,最终选用XDA-8大孔树脂,在优化后的最适工艺条件下,绿原酸含量可达70.9％,回收率达85.4％.进一步采用高效液相制备色谱获得了高纯度(95.2％)的绿原酸.所建立的绿原酸制备工艺操作简便、高效环保,产品功效明确,具有良好的市场应用前景.     

超声波辅助提取金银花中绿原酸的工艺优化

为提高金银花中绿原酸的提取率,应用响应面分析法优化提取绿原酸的工艺条件,在单因素试验基础上,采用Box—Behnken中心组合设计原理研究乙醇浓度、液料比、超声温度3个因素对金银花提取物中绿原酸含量的影响,利用Design—Expert8．0．5．0软件分析预测最佳提取工艺。根据优化结果确定绿原酸的最佳提取工艺为：乙醇浓度62％、液料比18．7：1mL／g、提取温度58℃、提取时间为40min。经验证试验表明该优化工艺简便稳定,重复性好,可用于金银花绿原酸的提取。     

绿咖啡豆绿原酸的体外抗氧化性活性测定

通过铁离子还原法和DPPH自由基清除法测定绿咖啡豆绿原酸的体外抗氧化活性,结果显示绿咖啡豆绿原酸具有抗氧化能力和清除自由基能力。稳定性试验结果表明,温度对绿咖啡豆绿原酸的DPPH自由基清除稳定性影响不显著;光照对稳定性有一定程度影响;pH值对稳定性影响显著,且绿咖啡豆绿原酸在酸性条件下比在碱性条件下稳定。     

响应面法优化红薯茎叶中绿原酸的提取工艺

以红薯茎叶为原料,采用超声波辅助乙醇浸提法提取红薯茎叶中的绿原酸。在单因素实验基础上,以提取时间、提取温度、料液比和乙醇浓度为考察因素,以绿原酸得率为响应值,采用4因素3水平响应面设计组合实验,建立相应的二项式数学模型优化提取工艺。实验结果表明,红薯茎叶中绿原酸提取的最佳工艺条件为提取时间25 min、提取温度64.5℃、料液比1∶35(g/mL)、乙醇浓度45%,红薯茎叶中绿原酸的实际得率为3.442 1 mg/g,接近预测值。响应面法可用于红薯茎叶中绿原酸提取工艺的优化。     

绿菇多糖的提取工艺优化

该文研究了绿菇多糖的超声波辅助提取方法。运用超声波辅助浸提、乙醇沉淀、Sevage法脱蛋白等步骤提取绿菇多糖,采用苯酚-硫酸法测定多糖含量。通过单因素实验考察超声功率、温度、超声时间和水料比等4个因素对多糖得率的影响,在此基础上采用Box-Benhnken响应面法设计四因素三水平试验,建立回归方程,研究各因素对绿菇多糖得率影响的程度,进一步优化提取工艺,得到了绿菇多糖超声波辅助法的最佳提取条件为超声功率500 W、温度76℃、超声时间40 min和水料比31 mL/g,多糖的得率为6.50%。因此,超声波辅助法有助于提高绿菇多糖的得率,响应面法建立的回归模型及相关参数的实际值与预测值之间的相关度较好,可以用于对超声波提取绿菇多糖进行分析和预测。     

杜仲叶中绿原酸提取工艺研究

采用单因素试验法对影响绿原酸提取率的主要因素进行了分析研究,利用响应面分析优化了提取绿原酸的最佳工艺条件:乙醇浓度52%,提取温度78℃;料液比1:13,提取时间2h,浸提两次。在最佳条件下绿原酸的提取率为2.38%,提取物得率18.38%,绿原酸含量12.97%。     

咖啡豆中咖啡因与绿原酸的研究进展

咖啡作为世界三大饮品之一,所含活性成分咖啡因和绿原酸具有多种药用价值,其提取和应用已成为目前研究的热点。综述了咖啡豆中绿原酸和咖啡因的定性与定量分析、提取与纯化、生理活性等方面的研究进展,以期为今后从咖啡豆中进行咖啡因与绿原酸的提取与应用研究提供科学参考。     

核桃花中绿原酸、新绿原酸和隐绿原酸的提取工艺响应面优化及其抗氧化活性研究

目的 探讨干燥核桃花中绿原酸、隐绿原酸和新绿原酸的最佳提取工艺及其抗氧化活性。方法 采用超声波辅助乙醇法提取核桃花中的绿原酸、新绿原酸和隐绿原酸, 以提取温度、乙醇体积分数、提取时间和料液比为自变量, 以得率的总评归一值(overall desirability, OD)为因变量, 应用响应面对提取工艺进行优化, 并通过体外实验评价了其抗氧化活性。结果 最佳提取工艺为：温度77℃, 乙醇体积分数67%, 提取时间28 min, 料液比1: 23(g/mL)。此时,绿原酸、新绿原酸和隐绿原酸的总提取率最佳, OD值可达0.91, 对DPPH自由基、ABTS自由基和羟自由基的半数抑制浓度(Half-maximal Inhibitory concentrations, IC50)值分别为41.63、41.68和34.43 μg/mL。结论 优选出的工艺稳定可行, 且提取液具有较好的体外抗氧化活性, 为核桃花中绿原酸类成分的进一步开发利用提供了理论基础。     

HPLC法同时测定绿咖啡豆中绿原酸及咖啡碱含量

建立一种高效液相色谱法(HPLC),可同时定量绿咖啡豆中绿原酸和咖啡碱的含量,并分析不同成熟度绿咖啡豆中绿原酸和咖啡碱含量变化。采用Agilent ZORBAX ODS-C18色谱柱,以0.5%乙酸水-乙腈为流动相,梯度洗脱,检测波长274 nm,流速1.0 m L/min,进样量10μL,柱温35℃。结果显示,绿原酸和咖啡碱的浓度线性范围分别为5.0 mg/L~100.0 mg/L(r~2=0.999 9)和5.1 mg/L~101.6 mg/L(r~2=0.999 9),检出限分别为0.25 mg/L和0.05 mg/L,相对标准偏差分别为1.56%和1.30%,回收率范围分别为98.86%~101.11%(RSD=1.02%)和98.70%~101.19%(RSD=0.83%)。     

Microwave-assisted extraction of chlorogenic acids from green coffee beans

Microwave-assisted extraction (MAE) has been considered as a potential alternative to conventional solvent extraction for the isolation of phenolic compounds from plants. Aqueous and alcoholic extracts of green coffee bean obtained by MAE were quantitatively analysed for total yield of extracts, chlorogenic acids, caffeine and total polyphenol content. The extracts were also evaluated for radical-scavenging activity, using 1,1-diphenyl-β-picrylhydrazyl radical. Under optimum conditions of time (5 min), temperature (50 °C) and wattage (800 W), the maximum chlorogenic acids and caffeine could be extracted with water as solvent. The extracts contained chlorogenic acids and caffeine in the ranges of 31–62% and 22–40%, respectively. The yields of MAE under optimum conditions were higher than those from the conventional solvent extraction at 5 min and 50 °C and the extracts showed radical-scavenging activity of >75%, even at the concentration of 25 ppm. The MAE process can thus be predicted and controlled for industrial application.     

咖啡生豆多糖提取及抗氧化活性

目的:为咖啡中多糖成分的研究和天然活性多糖的开发提供基础数据。方法:研究了云南小粒咖啡生豆多糖(GBP)的水提工艺和抗氧化活性。应用响应面法对咖啡生豆多糖提取工艺进行优化;运用傅里叶变换红外光谱(FT-IR)和扫描电镜(SEM)共同鉴定和表征咖啡生豆多糖的结构特点。采用DPPH自由基、ABTS自由基清除试验和FRAP法评估咖啡生豆多糖体外抗氧化能力。结果:咖啡生豆多糖水提法的最佳工艺条件：提取温度59℃、提取时间45 min、液料比(V_水∶m_咖啡生豆)21∶1 (mL/g)、浓缩体积1/8及乙醇体积分数75%,该条件下咖啡生豆多糖得率达9.56%。多糖样品经红外光谱和电镜扫描显示咖啡生豆是表面呈不规则的孔状结构的多糖。咖啡生豆多糖对DPPH自由基、ABTS自由基清除能力分别为2.32 mg/mL(IC₅₀)、0.011 mmol Trolox/g GBP,铁还原能力为0.95 mmol Fe²⁺/g GBP。结论:咖啡生豆多糖是具有抗氧化活性的不规则孔状结构多糖,具有进一步研究和开发的价值。     

Analysis of free amino acids in green coffee beans

For the determination of free amino acids in green coffee beans, 9-fluorenylmethylchloroformate was applied successfully as the precolumn derivatization agent. The separation of the 27 free amino acids of green coffee as yet identified or quantitatively determined is almost complete. The paper describes in detail the conditions of extraction, derivatization and resolution and presents reproducible data of standard curves and of quantitative results. It has been demonstrated that by applying the extraction procedure described, 99.8% of the free amino acids detectable by this method are extracted. On principle, Arabica and Robusta coffees contain the same main and minor amino acids. It was possible for the first time to determine the free amino acids ornithine, -alanine and pipecolic acid quantitatively in Arabica and Robusta coffees as well as hydroxyproline in Arabica coffees.

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Bestimmung freier Aminosäuren in grünen Kaffeebohnen. I. Bestimmung der Aminosäuren nach Vorsäulen-Derivatisierung mit 9-Fluorenylmethyloxycarbonylchlorid

Zusammenfassung Zur Bestimmung freier Aminosäuren in Rohkaffees wurde 9-Fluorenylmethyloxycarbonylchlorid als Vorsäulenderivatisierungsreagenz erfolgreich eingesetzt. Die Trennung der 27 in Rohkaffee bisher identifizierten bzw. quantitativ bestimmten freien Aminosäuren gelang weitestgehend vollständig. Extraktions-, Derivatisierungs- und Trennbedingungen sind detailliert beschrieben, Eichung sowie Ergebnisse der quantitativen Aminosäurenanalytik wurden statistisch abgesichert. Es konnte gezeigt werden, daß durch Anwendung des beschriebenen Extraktionsverfahrens 99,8% der mittels dieser Methode erfaßbaren freien Aminosäuren aus Rohkaffees extrahiert werden. Arabica- und Robusta-Rohkaffees weisen prinzipiell gleiche Haupt- und Minoraminosäuren auf. Erstmals wurden die freien Aminosäuren Ornithin, -Alanin und Pipecolinsäure in Arabica- und Robusta-Rohkaffees sowie Hydroxyprolin in Arabica-Rohkaffees quantitativ bestimmt.

     

Analysis of free amino acids in green coffee beans

To investigate amino acid changes in green coffee beans in the post-harvest period, amino acid concentrations were determined in green beans and after modelled drying, fermentation and storage. After the drying at alternating temperatures up to maximally 40°C, considerable changes in the concentrations of individual amino acids were identified. At the beginning of the storage period, significant changes in concentration were found to a minor extent. Under the condition of drying, it was mainly the concentration of glutamic acid that changed considerably. There was an increase in all the samples by 500 mg/kg dry matter on average, which corresponds to an increase of about 50% of the original value. In contrast, the concentration of aspartic acid in most of the samples decreased clearly due to drying. For the predominant part of the coffee samples, there was a significant increase in the hydrophobic amino acids Val, Phe, Ile and Leu. Changes of the quantities of other amino acids were non-uniform and only insignificant. Constant drying at 80°C for most of the amino acids brought about only minor concentration changes compared to those values obtained at 40°C. Modelled fermentation had no significant effect on the concentrations of the individual amino acids. After a 4-week storage of dried beans, amino acid concentrations did not change further. It is very possible that different post-harvest treatment parameters may influence the amount of aroma precursor compounds in the coffee beans.     

Isolation of chlorogenic acids from roasted coffee

Chlorogenic acid, neochlorogenic acid and Band 510 have been shown to survive the coffee roasting process. Pure samples of each isomer have been isolated from a commercially roasted coffee and are non-allergenic.     

响应面法优化咖啡生豆水提绿原酸工艺研究

以越南Robusta咖啡生豆为原料,采用水提方法提取绿原酸。通过单因素实验对料水比、提取温度、p H、提取时间等提取工艺参数进行研究,并通过响应面法优化提取工艺,建立二次多项数学模型。结果表明,单因素和响应面优化咖啡生豆水提绿原酸的最优工艺参数为:料水比1∶20、提取温度为81℃,提取时间为60 min,p H为3.6,绿原酸提取得率为3.27%。      

Separation and characterisation of chlorogenic acid‐rich conserves from green coffee beans and their radical scavenging potential

Methanolic extract (Me₁) obtained from low‐grade green coffee beans (LCB), which is one of the major by‐products in the coffee industry, was enriched with phenolics by different methods viz., partitioning in solvents, chromatographic separation using dowex & diaion HP20 resins and precipitation by lead acetate. Separated fractions and Me₁ were analysed for total polyphenol, chlorogenic acid, caffeine and radical scavenging activity (RSA). Chlorogenic acid isomers of Me₁ and the isolated fractions were analysed by HPLC. Me₁ found to contain total polyphenol (16.60 ± 0.4%), chlorogenic acids (CGAs) (29.60 ± 0.9%), caffeine (7.52 ± 0.2%) and exhibited RSA (92.50%) at 100 ppm concentration. Precipitation method resulted significantly (P ≤ 0.05) higher phenolics (46.33 ± 0.5%) as well as CGAs (43.50 ± 0.7%). HPLC analysis indicated that the composition of 5‐Caffeoylquinic acid (5‐CQA) was more in all the isolated fractions.     

The measurement of feruloylquinic acids and caffeoylquinic acids in coffee beans. Development of the technique and its preliminary application to green coffee beans.

This paper describes the development of a quantitative, colorimetric technique for the determination of feruloylquinic acids, caffeoylquinic acids and total chlorogenic acids in synthetic mixtures and green coffee beans. The results are analysed statistically and discussed with reference to previously published data.