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离子形态会对强酸性阳离子交换树脂的吸附能力及选择性产生影响,L-赖氨酸在不同pH值下存在4种离子形态,以不同pH值的赖氨酸发酵清液为试验对象,研究了在离子交换树脂吸附时树脂柱出口料液中赖氨酸含量、树脂柱吸附赖氨酸量、洗脱液纯度、98%硫酸消耗量的变化。试验结果表明:不同pH值的赖氨酸发酵清液上柱时,赖氨酸的收率、树脂柱吸附量没有明显不同,但pH值为4.5的赖氨酸发酵清液,经树脂柱后得到的洗脱液纯度最高,平均可达98.56%,而且调节pH值时浓硫酸消耗量较低。 相似文献
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茶叶中有效成分综合提取的研究 总被引:20,自引:0,他引:20
以绿茶为原料,采用ZJL大孔离了交换树脂和ZJX大孔吸附树脂从茶叶的浸提液中提取茶氨酸、咖啡因、茶多酚和茶多糖。通过对树脂的静态、动态吸附性能的实验研究,确定了咖啡因、茶氨酸、茶多酚及茶多糖联合分离提取的工艺。研究结果表明:该工艺能有效的从茶叶中提取咖啡因、茶氨酸和茶多酚,提取的咖啡因纯度达83.23%,提取率为1.9%,茶氨酸纯度达85.43%,提取率为0.94%,提取的茶多酚纯度达95.62%,提取率为12.35%,且茶多酚中的咖啡因含量低于0.7%,茶多糖的纯度达51%,提取率为1.1%。 相似文献
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本文考察不同极性大孔树脂、离子交换树脂、活性炭及硅胶等吸附介质对红曲菌深层发酵液中水溶性红曲黄色素的吸附分离性能。结果显示非极性大孔树脂DA201-C效果最好,该吸附过程符合Freundlich方程,吸附动力学符合准一级动力学模型,表明吸附不受单层吸附的限制;液膜扩散是吸附主要限速步骤,扩散速率常数为0.16 min-1。通过静态和动态吸附洗脱条件优化,运用SPSS对数据进行分析,发现静态吸附、解吸料液比为1:2,吸附、解吸时间15 min,解吸液100%乙醇,酸性条件解吸效果较好;动态吸附解吸流速为0.25 BV/min条件下,可得到高回收率(96.99%)、脱盐率(99.44%)和脱糖率(92.52%)的水溶性红曲黄色素,经初步扩大实验显示吸附解吸性能稳定。大孔树脂DA201-C分离纯化发酵液中水溶性红曲黄色素操作简单、快速、放大性能好,具有很好的工业化生产应用价值。 相似文献
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本文以茶叶粗茶多酚为原料,研究了大孔吸附树脂法分离纯化表没食子儿茶素没食子酸酯(EGCG)的工艺条件。本文首次报道,采用AB-8大孔树脂,在中温条件下以10%的乙醇为洗脱剂,可以获得纯度90%以上的EGCG,回收率可达90%以上,且产品中咖啡因含量可低于0.5%,本方法可适合工业化生产需要。 相似文献
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大孔树脂分离纯化紫甘蓝中的花色苷 总被引:1,自引:0,他引:1
《食品工业》2016,(4)
采用大孔吸附树脂法纯化紫甘蓝中的花色苷,考察不同极性树脂对花色苷的静态吸附性能及动态吸附性能和纯化效果的影响,确定紫甘蓝花色苷的纯化工艺条件。研究发现HPD 500树脂对花色苷的吸附选择性最好。以色价为标准,同时考虑到吸附率和解吸率,确定了HPD 500树脂对紫甘蓝中花色苷的纯化工艺条件。结果表明,HPD 500树脂纯化花色苷的最佳条件为:上柱液pH2.5,上柱液吸光度0.707,上柱液体积1.5 BV,吸附流速1.5 BV/h,洗脱流速1.5 BV/h,解吸液为质量分数60%的酸性乙醇(pH2.5)。最佳条件下得紫甘蓝花色苷色价为47.8,提高为初始值(2.3)的20.8倍。 相似文献
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《食品工业科技》2016,(10)
利用超滤和大孔树脂联用的方法对紫薯花色苷粗提液进行了纯化,考查了不同截留分子量超滤膜对花色苷粗提液的纯化效果。结果表明:截留分子量为10 ku的膜可有效透过花色苷和截留大分子物质,花色苷的透过率为86.54%,蛋白质截留率为93.67%,透过液的可溶性固形物含量降低了14.29%,透光率提高了23.78%。通过对6种不同极性的大孔吸附树脂对超滤透过液中花色苷的吸附及解吸能力的考查,发现LS-305的吸附性能较好。其动态吸附及解吸条件为:上样流速5.2 BV/h,上样量35 BV;60%乙醇洗脱体积为9 BV可洗脱完全。花色苷产品色价由纯化前的1.59提高到纯化后的32.89。HPLC分析表明超滤和树脂联用纯化方法未对紫薯花色苷成分造成影响。 相似文献
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ABSTRACT: The effect of photosensitized oxidation of conjugated linoleic acid in an oil-in-water (o/w) emulsion system was studied. Water-soluble natural antioxidants, including apple polyphenols from apple extract, green tea extract, 4-hydroxy-2(or 5)-ethyl-5(or2)-methyl-3(2H)-furanone(HEMF), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), and ascorbic acid, were tested for antioxidant activity in this system. The green tea extract showed the highest antioxidant activity followed by ascorbic acid. Apple polyphenols did not give significant antioxidant activity. HEMF and HDMF exhibited a prooxidant effect. The antioxidant activity of tea catechins was also investigated. Of them, EGCG and ECG exhibited antioxidant activity at 50 ppm, but the antioxidant activity between them was not significantly different ( P < 0.05). Comparatively, EC, EGC, and GCG showed no significant antioxidative effect at 50 ppm. When the concentration increased to 100 ppm, the antioxidant activity of ECG and EGCG significantly increased compared with that at 50 ppm, and EGCG had higher antioxidant activity than ECG. GCG also showed significant antioxidant activity at 100 ppm. EGCG exhibited the highest antioxidant activity among the tea catechins in the emulsion system at 100 ppm. 相似文献
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以抗氧化活性为筛选导向,采用醇沉、溶剂萃取、大孔树脂分离和半制备型液相色谱联用技术从远安黄茶啤酒中分离出8 个具有抗氧化作用的关键组分。进一步结合超高效液相色谱-四极杆飞行时间质谱联用技术对抗氧化组分进行分析,共鉴定出8 种化合物,分别为表没食子儿茶素((-)-epigallocatechin,EGC)、咖啡因、表没食子儿茶素没食子酸酯((-)-epigallocatechin gallate,EGCG)、表儿茶素(epicatechin,EC)、1,2,6-三没食子酰-β-D-葡萄糖、表儿茶素没食子酸酯((-)-epicatechin gallate,ECG)、柯里拉京(corilagin,Cor)和色氨酸(Trp)。抗氧化活性和定量研究发现,EGC、EGCG、EC、ECG和Cor是远安黄茶啤酒中的主要抗氧化物质,对酒体的抗氧化活性贡献可达54.61%。其中,EGCG的贡献值最大,其次为EGC、ECG、EC和Cor。本研究为鉴定茶啤酒中的关键抗氧化成分,实现高抗氧化啤酒产品的选择性研发提供了技术支撑。 相似文献
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本文通过胃肠道消化,研究了六堡毛茶、成品茶中主要酚类物质在的含量、抗氧化能力上的变化,并以成品茶乙酸乙酯相作为对照。说明六堡茶制作过程中成分的差异导致抗氧化活性上的变化。消化前,六堡毛茶中GA含量相对较高;六堡成品茶中咖啡碱含量相对较高。消化后,主要的酚类物质(GA、原儿茶酸、原花青素、EGCG、GCG和ECG)均有80~90%的下降。抗氧化性随之降低。GA、原花青素、EGCG、ECG和GCG在毛茶水提物中与抗氧化活性呈显著相关性,在六堡茶水提物中原花青素(0.994)、EGCG(0.997)呈极其显著相关。六堡毛茶和六堡成品茶的酚类含量分别为28.41%和17.87%,对应的抗氧化能力为16.73 mg/L和15.37 mg/L。消化以后,多酚含量分别下降了68.85%和69.72%,对应的抗氧化活性下降了88%和82%。六堡成品茶抗氧化功能下降比例更低,保持能力更强。最可能影响的抗氧化活性的物质为GA、原花青素、EGCG和ECG。 相似文献
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Jang-Eun LeeBum-Jin Lee Jin-Oh ChungHyun-Jung Shin Sang-Jun LeeCherl-Ho Lee Young-Shick Hong 《Food research international (Ottawa, Ont.)》2011,44(2):597-604
The metabolic behavior of green tea (Camellia sinensis) during tea fermentation was characterized by 1H NMR spectroscopy coupled with multivariate statistical analysis to provide comprehensive information on changes in metabolites induced by tea fermentation. Fourteen tea metabolites of epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), epigallocatechin-3-gallate (EGCG), theanine, alanine, acetate, quinate, glutamate, caffeine, sucrose, glucose, and gallate, as identified by 1H NMR spectroscopy, were responsible for metabolic differentiation between green tea and fermented tea by principal component analysis. During tea fermentation, levels of EC, EGC, ECG, EGCG, quinate, caffeine, and sucrose were decreased, whereas gallate and glucose levels were increased. In particular, unique changes in caffeine and gallate levels were observed during tea fermentation, which caffeine and gallate levels have been shown to vary after tea fermentation among many reports to date. This study highlights that metabolomics with global profiling and a highly reliable and reproducible 1H NMR spectroscopic data set can provide a better understanding of unique changes in tea metabolites during tea fermentation. 相似文献
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Extraction of Epigallocatechin Gallate and Epicatechin Gallate from Tea Leaves Using β‐Cyclodextrin 下载免费PDF全文
Lu Cui Yuxuan Liu Ting Liu Yahong Yuan Tianli Yue Rui Cai Zhouli Wang 《Journal of food science》2017,82(2):394-400
Use of organic solvents to extract phenolic compounds from plants may result in environmental pollution and cause health problems in persons. Replacing organic extraction solvents by green extracting agents without affecting the extraction yield is one of the most pressing problems to be solved. The aim of this study is to evaluate the capacity of β‐cyclodextrin (β‐CD) to recover phenolic compounds from tea leaves. The extract obtained using the ethanol/water mixture presented the highest total phenolic content, followed by those obtained using β‐CD solution and water. HPLC analysis of the extracts showed that the addition of β‐CD to the extracting agent had a selective effect on the extraction of epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). The extraction yield of EGCG and ECG using 15 g/L β‐CD were higher than that obtained using water and 50% ethanol. Molecular docking results indicated that the molecules of EGCG and ECG were more inclined to interact with β‐CD than epigallocatechin, epicatechin, and gallocatechin. The impact of β‐CD concentration, temperature, and time on EGCG and ECG extraction from tea leaves was investigated and the maximum amount of EGCG (118.7 mg/g) and ECG (54.6 mg/g) were achieved when extracted with 25 g/L aqueous β‐CD solution at 60 °C for 60 min. The present study indicates that aqueous β‐CD can be used as an alternative to organic solvents to recover EGCG and ECG from tea leaves. 相似文献
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Hyong Seok Park Hee Jin Lee Min Hye Shin Kwang-Won Lee Hojoung Lee Young-Suk Kim Kwang Ok Kim Kyoung Heon Kim 《Food chemistry》2007,105(3):1011-1017
Due to the adverse effects of the caffeine in a variety of plant products, many methods have been explored for decaffeination, in efforts to remove or reduce the caffeine contained in plant materials. In this study, in order to remove caffeine from green tea (Camellia sinensis) leaves, we have employed supercritical carbon dioxide (SC–CO2), which is known to be an ideal solvent, coupled with a cosolvent, such as ethanol or water. By varying the extraction conditions, changes not only in the amount of caffeine, but also in the quantities of the principal bioactive components of green tea, including catechins, such as epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC), were determined. The extraction conditions, including temperature, pressure and the cosolvent used, were determined to affect the efficacy of caffeine and catechin extraction. In particular, the type and concentration of a cosolvent used constituted critical factors for the caffeine removal, combined with minimal loss of catechins, especially EGCG. When the dry green tea leaves were extracted with SC–CO2 modified with 95% (v/v) ethanol at 7.0 g per 100 g of CO2 at 300 bar and 70 °C for 120 min, the caffeine content in the decaffeinated green tea leaves was reduced to 2.6% of the initial content. However, after the SC–CO2 extraction, a substantial loss of EGCG, as much as 37.8% of original content, proved unavoidable. 相似文献
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Polyphenolic composition and in vitro antioxidant activities of native‐ and tannase‐treated green tea extracts 下载免费PDF全文
Chong‐Boon Ong Mohamad S. M. Annuar 《International Journal of Food Science & Technology》2017,52(3):748-756
The antioxidant activities of native‐ and tannase‐treated green tea extracts along with their major polyphenol components were investigated. The polyphenolic content and composition of the tea before and after tannase treatment were determined by liquid chromatography coupled with mass spectrometry (LC‐MS). Approximately 99% of the (?)‐epigallocatechin gallate (EGCG) and (?)‐epicatechin gallate (ECG) in green tea extract were converted by tannase to (?)‐epigallocatechin (EGC) and (?)‐epicatechin (EC), respectively, after 30 min. Biotransformed green tea exhibited a significantly higher DPPH˙ radical scavenging activities than native green tea (EC50 value of 0.024 ± 0.001 and 0.044 ± 0.001 mg mL?1, respectively). Kinetic parameters such as scavenging rate and stoichiometry were calculated. The rate of DPPH˙ radical scavenging activities for tannase‐treated green tea extract was shown to be higher than native green tea extract. 相似文献
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Wisuitiprot W Somsiri A Ingkaninan K Waranuch N 《International journal of cosmetic science》2011,33(6):572-579
Catechins are major antioxidants in green tea (Camellia sinensis or Camellia assamica), but because they do not permeate the skin well, the application of green tea in cosmetic products has so far been limited. This study aims to evaluate the cutaneous absorption of catechins from an extract of green tea and from a green tea extract-loaded chitosan microparticle. The catechin skin metabolism was also examined. The results suggest that chitosan microparticles significantly improve the ability of catechins to permeate skin. The cutaneous metabolism of the catechins significantly affected their permeation profiles. Epicatechin (EC) and epigallocatechin (EGC) penetrated the skin more than epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). The galloyl groups in EGCG and ECG were enzymatically hydrolysed to EGC and EC, respectively. Dehydroxylation of catechins was also observed. Chitosan microparticles effectively prevented enzymatic changes of the catechins; therefore, chitosan microparticles are here found to be the promising carriers for enhancing the skin permeation. 相似文献