黑蒜中呈色物质5-羟甲基糠醛的分离鉴定及其生成动力学

Isolation and identification of color material 5-hgdroxy methy furfural from black garlic and its kinetic formation

为探究黑蒜中的呈色物质及其生成规律,将黑蒜破碎、乙酸乙酯萃取、真空硅胶柱分离后得到黑色的石油醚-乙酸乙酯-甲醇(体积比=99∶99∶1)洗脱部分,经电喷雾质谱(ESI-MS)和高效液相色谱(HPLC)加标鉴定,然后用HPLC测定不同温度不同熟化时期物料中该呈色物质的含量,进而对数据进行拟合。经ESI-MS和5-羟甲基糠醛(5-HMF)标准品内加法表明:石油醚-乙酸乙酯-甲醇(体积比=99∶99∶1)洗脱部分主要是5-HMF;另外,在不同温度条件下,随着熟化时间延长,5-HMF含量亦有不同增加,通过数据拟合发现黑蒜中的5-HMF生成属于一级反应,其阿雷尼乌斯公式是:ln K=-3 862.5(1/T)+7.98(式中:K为反应速率常数,min-1;T为绝度温度,K),其反应活化能为32.11 kJ/mol。这些结果证实黑蒜的主要呈色物质之一是5-HMF,同时得到了其反应活化能。

The purpose of the study was to identify the mechanism of the black color formation in black garlic. Black garlics were homogenized, extracted with ethyl acetate and separated by vacuum silica gel column. The black petroleum ether-ethyl acetate-methanol （99： 99：1 ） elution fraction was identified by electrospray ionization mass spectrometry（ESI-MS） and high performance liquid chromatography（HPLC）. Then the contents of the color material in different temperature and ripening period were determined by HPLC and the data were simulated. The results showed that the petroleum ether-ethyl acetate-methanol （99： 99：1 ） elution fraction mostly contained 5-HMF. This identification was done by ESI-MS which adds standard 5-HMF into samples. In addition, the content of 5-HMF increased with ripening period in different temperature. The formation reaction belonged to first order reaction through data fitting and the activation energy was 32.11kJ/mo applying to arrhenius formula. This study confirmed that 5-HMF is one of the color materials. Meanwhile the reaction activation energy of 5-HMF was obtained, which provided the reference for the optimization of black garlic processing and the quality control of black garlics.