栝楼皮叶黄素的超临界CO_2萃取及其稳定性研究

Lutein in Fruit Peel of Trichosanthes kirilowii Maxim. by Supercritical CO_2 Extraction and Its Stability

对栝楼(Trichosanthes kirilowii Maxim.)皮超临界CO2萃取叶黄素及其理化性质进行研究。响应面法(response surface methodology,RSM)优化栝楼皮叶黄素超临界CO2萃取工艺,Design Expert软件对实验数据进行分析,固定时间150min和粒径0.25～0.42mm,φ(乙醇)=95%为夹带剂。最佳工艺参数为压力26.6MPa,温度52.8℃,流量为15.7L/h,得率为4.76g/100g,叶黄素质量分数为14.99%,最大吸收波长445nm。光对其稳定性影响很大,在日光下放置7d后叶黄素吸光值下降86.57%。对热较稳定,但随温度的升高和时间延长,叶黄素吸光值下降较快,90℃加热3h叶黄素吸光值降低17.48%;强酸(pH=1～4)对叶黄素破坏强,中、碱性条件下叶黄素较稳定;金属离子Fe3+、Fe2+、Cu2+、Al3+、Mg2+对叶黄素破坏作用强,放置4d,其吸光值分别下降29.23%、20.70%、30.80%、23.53%、30.93%;Mg2+出现少量絮状沉淀,而Zn2+、Ca2+、K+、Na+对叶黄素无影响;H2O2、维生素C和柠檬酸对叶黄素有轻微的破坏作用,苯甲酸钠、ρ(Na2SO3)=0.2～0.4g/L对叶黄素有增色作用;蔗糖对其无影响。

Supercritical carbon dioxide（SC-CO2） fluid extraction of lutein in fruit peel of Trichosanthes kirilowii Maxim. and the physical and chemical properties of lutein were investigated. The response surface methodology（RSM） was employed to optimize the process variables of three major factors. Experimental data were analyzed by solving the regression equation with the Design Expert Software. Fixed the particle size（0.25 -0.42） mm and time 150 min,φ（ethanol） =95% as the entrainer. The optimum process parameters were obtained as ： pressure, 26.6 MPa; temperature, 52. 8 ℃ ; CO： flow rate, 15.7 L/h, at which the yields were 4.76 g/100 g and lutein mass fraction was 14.99%. The maximum absorption spectrum of the lutein was 445 nm. Light has a great influence on the stability of lutein. The absorbance of lutein decreaced 86. 57 % under the sunlight 7 days. The lutein were relatively stable against heat but lutein degradation could be accelerated with the decreased preservation rate under long time and high temperature,90 ℃ heating for 3 h, the absorbance of lutein decreaced 17.48%. The lutein could degrade significantly under acid conditions（ pH = 1 -4）, but more stable in the neutral and alkaline conditions. The lutein were unstable with decreased preservation rate with Fe^3＋,Fe^2＋, Cu^2＋, Al^3＋, Mg^2＋ solution to place 4 d, lutein absorbance values decreased 29.23%, 20. 70% ,30. 80% , 23.53% , 30. 93%. a small amount of flocculent precipitate appears in Mg^2＋ solution and while stable with Zn^2＋ , Ca^2＋ , K ^＋ , Na^＋. H2O2, ascorbic acid and citric acid has minor damage,sodium benzoate and low concentration ρ（ Na2SO3 ） =0.2 -0.4 g/L can enrich its color. In addition, sucrose has no effect on the lutein.