油溶性胭脂红酸衍生物的制备及性质评价

The preparation and properties of oil- soluble derivatives of carminic acid

胭脂虫红色素是一种水溶性极好却不溶于大多数有机溶剂及油脂类的天然红色素,为了改善其油溶性从而拓展其运用领域,可对胭脂红色素的有效染色成分胭脂红酸进行结构修饰。本文通过对胭脂红酸进行甲酯化、酰化两步化学反应制备了5种胭脂红酸衍生物,应用傅里叶变换红外光谱(FTIR)对5种产物进行了结构的初步表征,借助紫外-可见(UV-Vis)光谱等方法考察了产物的溶解性及酸、碱、光、热、金属离子对产物稳定性的影响。结果表明5种产物的主要成分中增加了酯基和烷基;产物可溶于有机溶剂和油类物质,在玉米油中的溶解度从高至低的顺序为CE5>CE2>CE4>CE1>CE3,其中产物CE5在玉米油中可溶解12.8 g/L;产物在中性溶液中较稳定,光及热稳定性良好,金属离子Cu^(2+)、Fe^(3+)和Al^(3+)可使色素产物褪色,而Na+和Mg^(2+)却能增色。5种胭脂红酸衍生物油溶性及稳定性良好,且保留了胭脂虫红色素的优良染色能力,具有潜在的应用价值和前景。

Cochineal extract（ Dactylopius coccus costa） is one of the most valuable water- soluble natural red pigments.In order to improve its solubility in organic solvents and oil,the method of chemical structure modification was applied.Five oil- soluble derivatives of carminic acid which was the main ingredient of cochineal extract were designed and prepared through two- step reactions in this paper.The structure of the products was characterized by fourier transform infrared spectroscopy（ FTIR）,the solubility and stable properties in the presence of acid,alkali,light,heat,or metal ions had been investigated. The results showed that ester group and alkyl group were introduced to carminic acid which were proved by FTIR.The five products could easily be dissolved in organic solvents and oil.Descending order of their solubility in the corn oils was CE5 CE2 CE4 CE1 CE3.Solubility of the derivative CE5 reached 12.8 g / L.The products were stable in the presence of light and have excellent thermal stability.Metal ion Cu^2＋,Fe^3＋ and Al^3＋could make products fade,but products graced in the presence of Na＋and Mg^2＋.With the heritage of dyeing ability of cochineal extract,the five derivatives were proved with good stability and high solubility in oil,therefore,the search had become important to further application of cochineal extract.