Aristotle University of Thessaloniki, Chemistry Department, Thessaloniki, Greece.
Anal Chim Acta. 2012 Nov 28;755:77-85. doi: 10.1016/j.aca.2012.10.016. Epub 2012 Oct 13.
An ultrasound assisted extraction method is proposed for the recovery of bioactive glycosides (i.e. crocins and picrocrocin) from Crocus sativus L. dry stigmas using aqueous methanol. Response surface methodology (RSM) was employed to optimize the extraction parameters, namely, the percentage of methanol (%), the duration (min) and the duty cycles (s) of sonication. Optical microscopy, spectrophotometry and RP-HPLC-DAD were employed to follow pros and cons of the process. Additional experiments were conducted to compare recoveries with those under other agitation conditions (e.g. magnetic stirring according to ISO 3632-2 standard). The percentage of methanol, the sonication duration and duty cycles combination that can be recommended as optimum for the recovery of crocins and picrocrocin were 50%, 30 min, 0.2s and 0.44%, 30 min, 0.6s, respectively. Picrocrocin levels were not influenced dramatically under the optimum conditions for crocins extraction (11±2 instead of 12±1 mg kg(-1) dry stigmas, respectively) so that these can be considered optimum for both categories of tested compounds. Ultrasound assisted extraction speeded up further recovery of these precious apocarotenoids. Our findings for extraction conditions are useful for both industrial and analytical applications and should be considered in a forthcoming revision of the ISO 3632-2 technical standard.
提出了一种超声辅助提取法，用于从干燥的藏红花柱头中回收生物活性糖苷（即藏红花酸和藏红花苦素），使用的提取溶剂为水-甲醇。响应面法（RSM）用于优化提取参数，即甲醇的百分比（%）、超声时间（min）和超声占空比（s）。光学显微镜、分光光度法和反相高效液相色谱-二极管阵列检测法（RP-HPLC-DAD）用于跟踪该过程的优缺点。还进行了额外的实验，以比较与其他搅拌条件（例如根据 ISO 3632-2 标准进行的磁力搅拌）下的回收率。可以推荐 50%甲醇、30 分钟超声时间和 0.2s 超声占空比的组合作为藏红花酸和藏红花苦素回收的最佳条件；30 分钟超声时间和 0.6s 超声占空比的组合则可作为最佳条件用于回收藏红花苦素。在藏红花酸提取的最佳条件下，藏红花苦素的水平没有受到显著影响（分别为 11±2 而不是 12±1mg kg(-1)干柱头），因此这些条件可以被认为是这两种被测试化合物的最佳条件。超声辅助提取进一步加速了这些珍贵的类胡萝卜素的回收。我们对提取条件的研究结果对工业和分析应用都很有用，应在即将修订的 ISO 3632-2 技术标准中予以考虑。
