共查询到20条相似文献,搜索用时 93 毫秒
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为了考察丙酮酸钠对S-腺苷蛋氨酸(SAM)和谷胱甘肽(GSH)联产发酵的影响,本文通过在不同培养时间向摇瓶中添加不同浓度丙酮酸钠,发现0 h添加2 g/L丙酮酸钠最有利于SAM和GSH生物合成。在该条件下进行分批发酵培养,结果表明:SAM和GSH联产量在27 h时达到最大值402.3 mg/L,比不添加丙酮酸钠的对照提高了35.1%。进一步地,对酵母胞内SAM合成酶、γ-谷氨酰半胱氨酸合成酶、己糖激酶、异柠檬酸脱氢酶的活性以及NADH和ATP含量进行测定,结果发现:丙酮酸钠添加不仅提高了SAM和GSH代谢途径中的关键酶活性,还提高了胞内能量代谢物质的水平,最终提升了SAM和GSH的合成能力,实现了SAM和GSH的联合高产。该研究结果为类似耗能合成化合物的高效生产提供了一种可行的思路。 相似文献
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微波破碎酵母细胞提取海藻糖的研究 总被引:7,自引:0,他引:7
采用微波预处理的方法破碎酵母细胞后,分别用水、乙醇、三氯乙酸来提取海藻糖,结果表明,海藻糖的提取效果明显好于没有用微波预处理的对照组,由Mathematice2.2软件分析可以看出;提取时,微波预处理时间是最显著的影响因素。其最佳值为2min;用三氯乙酸作溶剂结果好于乙醇和水。 相似文献
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枇杷核黄酮类物质微波法提取及对羟自由基清除作用研究 总被引:4,自引:0,他引:4
本文对微波法提取枇杷核中黄酮类物质进行了研究,通过单因素及L9(3^4)正交试验,得到最佳工艺条件:m(乙醇溶液)/m(枇杷核)=15,提取功率为296W,时间120s提取3次,50%的乙醇溶液。按此最佳方法总黄酮提取率为1.41%。微波法与传统溶剂提取法比较,具有提取时间短、提取率高等优点。同时研究了该提取物对羟自由基清除作用,黄酮类物质对羟自由基的清除作用呈线性相关,相关系数R^2为0.9865。 相似文献
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Zohar Kerem Hilla German‐Shashoua Oded Yarden 《Journal of the science of food and agriculture》2005,85(3):406-412
Growing interest in plant secondary metabolites has brought with it the need for economical, rapid and efficient extraction protocols. Microwave‐assisted extraction (MAE) was used to extract saponins from chickpea (Cicer arietinum). Several MAE conditions were tested, and the method proved to be superior to Soxhlet extraction with regard to amounts of solvents required, time and energy expended. The use of a butanol/H2O mixture showed selectivity towards saponin extraction. Using TLC, two distinct saponins were observed in the various chickpea extracts. The identification of the major saponin as a DDMP‐conjugated saponin was verified using 1H and 13C NMR, for the first time in chickpea. The MAE procedure most likely contributed to the conservation of the heat‐sensitive DDMP moiety. The pure chickpea saponin exhibited significant inhibitory activity against Penicillium digitatum and additional filamentous fungi. Two Fusarium strains tested were highly tolerant to the saponin. The potential for using MAE for the efficient extraction of natural products may assist in expediting the chemical analysis and characterization of the biological activities of such compounds. Copyright © 2004 Society of Chemical Industry 相似文献
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柚皮黄酮类物质的微波辅助提取及其抗氧化活性研究 总被引:6,自引:4,他引:6
研究了微波对柚皮中黄酮类物质的提取及其抗氧化活性的影响。同时还研究了水提法、乙醇回流提取法、微波提取法获得的柚皮提取液对羟自由基、超氧阴离子自由基的清除作用,以及对小鼠的肝组织脂质过氧化的抑制作用。与水提法、乙醇回流提取法相比,微波法所得提取液对自由基清除率及脂质过氧化的抑制作用较强。其半抑制率浓度分别为33.24,111.78,12.28mg/mL。说明微波提取法能很好的应用于黄酮类物质的提取,同时不会破坏其抗氧化活性。 相似文献
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微波辅助法萃取当归多糖的条件优化 总被引:22,自引:0,他引:22
采用单因素试验和正交试验 ,进行了微波辅助萃取当归多糖的研究 ,得到了微波辅助萃取当归多糖的最佳工艺条件 :m(水 ) /m(当归粉 ) =9,微波功率 45 0W ,萃取 2次 ,每次萃取 4min。萃取液经真空浓缩 ,用活性炭脱色后 ,加入乙醇使多糖沉淀 ,过滤 ,沉淀用乙醇洗涤多次 ,真空干燥后即为当归多糖 ,产率 1 5 2 %,多糖质量分数 91 6%。与直接加热萃取法进行比较 ,结果表明 ,微波辅助萃取能大大缩短萃取时间 ,降低萃取剂用量 ,并能提高当归多糖产率。 相似文献
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Green Extraction Methods for Polyphenols from Plant Matrices and Their Byproducts: A Review 下载免费PDF全文
Kashif Ameer Hafiz Muhammad Shahbaz Joong‐Ho Kwon 《Comprehensive Reviews in Food Science and Food Safety》2017,16(2):295-315
Polyphenols as phytochemicals have gained significant importance owing to several associated health benefits with regard to lifestyle diseases and oxidative stress. To date, the development of a single standard method for efficient and rapid extraction of polyphenols from plant matrices has remained a challenge due to the inherent limitations of various conventional extraction methods. The exploitation of polyphenols as bioactive compounds at various commercial levels has motivated scientists to explore more eco‐friendly, efficient, and cost‐effective extraction techniques, based on a green extraction approach. The current review aims to provide updated technical information about extraction mechanisms, their advantages and disadvantages, and factors affecting efficiencies, and also presents a comparative overview of applications of the following modern green extraction techniques—supercritical fluid extraction, ultrasound‐assisted extraction, microwave‐assisted extraction, pressurized liquid extraction, and pressurized hot water extraction—as alternatives to conventional extraction methods for polyphenol extraction. These techniques are proving to be promising for the extraction of thermolabile phenolic compounds due to their advantages over conventional, time‐consuming, and laborious extraction techniques, such as reduced solvent use and time and energy consumption and higher recovery rates with lower operational costs. The growing interest in plant‐derived polyphenols prompts continual search for green and economically feasible modern extraction techniques. Modern green extraction techniques represent promising approaches by virtue of overcoming current limitations to the exploitation of polyphenols as bioactive compounds to explore their wide‐reaching applications on an industrial scale and in emerging global markets. Future research is needed in order to remove the technical barriers to scale‐up the processes for industrial needs by increasing our understanding and improving the design of modern extraction operations. 相似文献
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