苦荞麸皮黄酮类化合物的微波辅助提取和HPLC-ESI-MS^n测定

MICROWAVE-ASSISTED EXTRACTION AND HPLC-ESI-MS^n DETERMINATION OF FLAVONOIDS FROM TARTARY BUCKWHEAT BRAN

以苦荞(F.tataricum(L.)Gaertn)麸皮为试材,采用HPLC-UV和HPLC-ESI-MSn测定技术研究了麸皮中黄酮类化合物用微波辅助提取工艺的最佳条件及其提取过程中黄酮类化合物各化学组分的动态变化。结果表明,苦荞麸皮黄酮类化合物的最佳提取工艺条件为微波加热时间15min,乙醇体积分数40%,压力400kPa。在此条件下总黄酮提取产率达20.6μmol/g,其组分芦丁、槲皮素、表儿茶素分别达11.2、5.6和3.8μmol/g。在提取压力超过400kPa时,芦丁开始失去一个芸香糖转化为槲皮素;随着微波照射时间的延长,芦丁、表儿茶素和槲皮素提取产率先增加,而后下降。提取压力越大,提取速率越快,分解速度也越快,达到最高提取产率的时间越短。

Themicrowave-assisted extraction of optimum conditions and the chemical composition changes of the flavonoids from tartary buckwheat bran were studied by using HPLC-UV and HPLC-ESI-MSn determination methods. The result showed that the optimum extraction conditions were as follows： microwave irradiation time was 15min;the concentration of ethanol was 40 % （v/v） ; the pressure was 400kPa. Under the above conditions, the extraction yield of total flavonoids was 20.6μmol/g, rutin was 11.2μmol/g, quercitrin 5.6μmol/g, epicatechin 3.8μmol/g. The rutin in the extract could be partly decomposed when pressure was over 400kPa, as a result of quercetin increased by the loss of rutinosyl from rutin. With the increase of microwave extraction time, extraction yields of rutin, epicatechin, quercitrin and quercetin were firstly increased and then decreased. The higher the pressure was, the faster the extraction rate and the decompositionrate were, and the shorter the extraction time for obtaining the highest yield was.