双水相分离火龙果皮中色素和果胶

利用双水相系统同时分离火龙果皮中的天然红色素和果胶，提高火龙果皮资源的利用。以火龙果皮为原料，采用PEG/硫酸铵双水相体系分离火龙果皮中的色素和果胶。分析PEG相对分子质量、PEG质量分数、体系pH、硫酸盐质量分数4个因素对色素与果胶分离的影响。结果表明，随着双水相PEG和盐的质量分数增加，火龙果皮中的色素和果胶得率随之增加；当相比接近0.5时，上相中色素和下相中果胶获得较佳的分离。最佳的双水相分离条件为:利用质量分数16%的PEG6000，质量分数19%硫酸铵双水相体系，pH4.0，在此条件下，富集在上相的红色素和下相的果胶得率分别为1.82%±0.04%、3.68%±0.13%。因而，采用双水相萃取技术不仅可以同时分离火龙果皮中色素和果胶，还具有萃取条件温和、工艺简单、得率高的优点，本研究为火龙果皮的综合利用和开发提供了实验依据。

Separation of Pigment and Pectin from Pitaya Peel by Aqueous Two-phase System

The natural red pigment and pectin in pitaya peel were separated simultaneously by aqueous two-phase system(ATPS)to promote the development of pitaya peel resource.Taking pitaya peel as raw material,the extraction of red pigment and pectin from pitaya peel by PEG/(NH 4)2SO 4 ATPS was studied.Four different factors followed as PEG relative molecular weight,weight fraction of PEG,system pH,weight fraction of ammonia sulfate were investigated based on the extraction yield of red pigment and pectin from pitaya peel.The results showed that the extraction yield of pigment and pectin increased with the increasing of the weight fraction of PEG and ammonia sulfate.When the phase ratio was close to 0.5,the pigment in the upper phase and pectin in the lower phase showed better separation.The optimum conditions for ATPS was pH4.0 using ATPS of PEG6000 and ammonia sulfate,with the weight fraction of 16%and 19%,respectively.Under these conditions,the extraction yield of the desired red pigment enriched in the upper phase of ATPS was 1.82%±0.04%,while the pectin was enriched in the lower phase of ATPS with an extraction rate of 3.68%±0.13%.In conclusion,the ATPS could simultaneously separate pigment and pectin from pitaya peel,with the advantages of mild operational conditions,simple process and high yield.The study was supposed to provide the experimental basis for the comprehensive utilization and development of pitaya peel.