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991.
992.
993.
丝瓜中的皂甙及其生物活性 总被引:2,自引:0,他引:2
详述了国内外丝瓜中皂甙的提取和分离过程,概括了其组成及结构和生物活性研究,并对丝瓜的利用前景进行了分析. 相似文献
994.
The multistage extraction installations using cross-flow and back-flow schemes are successful in hops extraction. Both types of extraction process have been investigated, comparing the installations in order to specify the most appropriate scheme and determine the number of stages required. A three stage extraction with separation of a part of the solid phase between the stages was carried out. The parameters of each extraction stage of a cross-flow and a back-flow installation were calculated. It was established that in the cross-flow scheme the third stage was unnecessary since a minimal part of the bitter substances was extracted in it and the extract yield was too low. Moreover in the cross-flow installations a very high extraction efficiency was achieved, (94, 67%) but with a large consumption of extracting solvent (3,24.10?2m3/kg) whilst in the back-flow scheme the extraction efficiency was much lower (71,4%) but with a reduced solvent consumption (1,2.10?2m3/kg). The comparison of both installations demonstrates that the back-flow scheme is not very successful and that it is advisable to use a cross-flow installation with one or at most two extraction stages. The results obtained enable the proposal of a more rational scheme of hops extraction, where a one or two stages cross-flow process with separation of a part of the solid phase results in a final granulated product, a mixture of the extract and partly extracted raw material. 相似文献
995.
Extraction of ginger rhizome: kinetic studies with acetone 总被引:2,自引:0,他引:2
Ground sieved Jamaican ginger rhizome has been treated with acetone under various conditions and, in each case, the concentration of [6]-gingerol extracted was measured as a function of time. The results could be expressed by two intersecting first-order plots and an initial intercept, representing very rapid initial extraction, followed by a fast stage and a subsequent slow stage. At 30°C the rate constant of the slow stage was c. 95 times smaller than that of the fast stage and its activation energy was 3.6 times larger. The fast stage was not affected by solvent flow into the ginger particles, or by an increase in the stirring speed. These findings, together with the fact that both first-order rate constants were inversely proportional to the square of the radius of the particles, pointed to [6]-gingerol diffusion through the solid ginger as the rate-determining step. The data could also be fitted by the equation of So and MacDonald (1986). The relevance of the research to the industrial production of ginger oleoresin is pointed out. 相似文献
996.
研究应用溶剂萃取耦合傅里叶红外光谱(FTIR)技术建立快速分析食用油中微量水分的方法。数据显示乙腈是最佳萃取溶剂,其起始含水量300μg/g时对乙腈的萃取能力无明显影响。乙腈/油脂比例为1.5~2∶1效果较佳,定量基于差谱的二阶导数明显优于差谱,对于萃取水分的乙腈波谱中HOH弯曲振动1 631 cm-1最优,灵敏度高于OH伸缩振动3 630 cm-1和3 541 cm-1。对所有测试样品,FTIR法的结果与标准卡尔费休法高度一致,并表现出优良的准确性和精确性(标准差~30,变异系数3%)。研究表明溶剂萃取耦合FTIR快速分析食用油中微量水分切实可行。 相似文献
997.
998.
999.
双液相萃取菜籽粕蛋白提取工艺条件的选择 总被引:5,自引:1,他引:5
以宁油七号双液相萃取菜籽粕为研究对象,采用正交试验和单参数条件试验相结合的方法,就菜籽分离蛋白提取过程的有关工艺参数进行了研究。试验表明,在一定的pH值下,温度是影响菜籽蛋白萃取率的最显著因素。在保证良好搅拌的条件下,菜籽蛋白萃取过程表现为速率控制过程,水粕比对蛋白萃取率影响不大,而萃取时间对菜籽蛋白萃取率有显著影响。宁油七号双液相萃取粕蛋白质的最佳萃取工艺参数,宜选取温度40℃,水粕比15,时间60min,pH=12。在该条件下菜籽蛋白的萃取率为71.5%,植酸萃取率为33.6%。 相似文献
1000.
南瓜多糖的提取工艺研究 总被引:2,自引:0,他引:2
通过南瓜多糖提取工艺实验,确定了浸提、活性炭脱色过程的较优工艺参数。 相似文献