基于化学修饰法制备油溶性栀子蓝色素及其性能表征研究

主要采用化学修饰法制备油溶性栀子蓝色素,对其制备工艺条件进行优化并评价其性能表征。采用硬脂酰氯对栀子蓝色素分子结构进行化学修饰,利用单因素逐级试验优化工艺条件,经SEM、FTIR及紫外-可见分光光度法对目标产物进行结构表征,并评价油溶性栀子蓝色素在不同条件下的溶解性和稳定性。结果表明,制备最佳工艺条件为反应物摩尔比n_{水溶性栀子蓝色素}∶n_硬脂酰氯∶n_三乙胺为1∶5∶5,反应温度为40℃,反应时间为30 h,在此条件下目标产物产量为(402±8.2)mg,色价为26.3±0.6;紫外-可见光谱图显示油溶性栀子蓝色素的最大吸收波长为624 nm;观察微观形貌发现化学改性前后栀子蓝色素微粒呈现明显不同的微观结构;FTIR分析显示目标产物在2919.98 cm^-1和2851.17 cm^-1处出现极强的吸收峰,而C-O、C-O-C-O和C-C的特征吸收峰明显降低,表明经化学改性发生了酯化反应,引入了脂肪酸长链和酯基等疏水性基团;栀子蓝色素衍生物可溶于丙酮,易溶于乙酸乙酯、石油醚和食用油等溶剂;制得的油溶性栀子蓝色素在室内散射光强度、阴暗避光条件及低温条件下稳定性良好。该研究得到一种油溶性栀子蓝色素的最佳工艺条件,一定程度上扩大了栀子蓝色素在食品中的应用范围。

The Preparation and Characterization of Oil-Soluble Gardenia Blue Pigment Based on Chemical Modification Method

The oil-soluble gardenia blue pigment is prepared by chemical modification method and its preparation conditions are optimized and the properties are evaluated.The molecular structure of gardenia blue pigment is chemically modified by stearyl chloride,and the technological conditions are optimized by single factor step test.The structure of the target product is characterized by SEM,FTIR and UV-visible spectrophotometry,and the solubility and stability of oil-soluble gardenia blue pigment under different conditions are evaluated.The optimum preparation conditions are determined as follows:the molar ratio of reactants water-soluble gardenia blue pigment,stearyl chloride and triethylamine is 1∶5∶5,the reaction temperature is 40℃,the reaction time is 30 h,under such conditions,the yield of the target product is(402±8.2)mg and the color value is 26.3±0.6.UV-vis spectra show that the maximum absorption wavelength of oil-soluble gardenia blue pigment is 624 nm.The microstructures of gardenia blue pigment particles are obviously different before and after chemical modification.FTIR analysis results show that the target product has extremely strong absorption peaks at 2919.98 cm^-1 and 2851.17 cm^-1,while the characteristic absorption peaks of C-O,C-O C-O and C-C are decreased significantly,which show that the esterification reaction occurs after chemical modification,and hydrophobic groups such as fatty acid long chain and ester group are introduced.The derivative of gardenia blue pigment is soluble in acetone and easily soluble in the solvents such as ethyl acetate,petroleum ether and edible oil.The prepared oil-soluble gardenia blue pigment has good stability under indoor scattered light,dark and low temperature conditions.In this study,the optimal technological conditions of oil-soluble gardenia blue pigment are obtained,which have expanded the application range of gardenia blue pigment in food to a certain extent.