茶叶特征香气组分的渗透汽化富集

Concentration of valuable tea aroma components by pervaporation

研究2种不同支撑体的聚二甲基硅氧烷/聚偏氟乙烯(PDMS/PVDF)膜和PDMS/Al2O3膜对茶叶特征香气成分顺式-3-己烯醇(叶醇)、芳樟醇、反式-2-己烯醛以及苯甲醇回收的分离性能。考察操作条件对4种芳香物单组分和混合组分的渗透汽化性能的影响。结果表明:渗透汽化膜对单组分实验芳香组分具有较好的分离因子,随着组分浓度的增加,芳香物的分离因子下降;随着温度的升高,分离因子呈先上升后下降的趋势。在芳香物质量分数为0.01%、温度为30℃的条件下,叶醇、芳樟醇、反式-2-己烯醛和苯甲醇的分离因子分别为64.5、31.5、29.3和28.9。混合体系中各组分的分离因子较单组分体系下降。PDMS/PVDF复合膜比PDMS/Al2O3复合膜具有更高的芳香组分分离因子和芳香物分通量。

Tea aroma component recovery by polydimethyl siloxane / polyvinylidene fluoride（ PDMS /PVDF） membrane and PDMS / Al2O3 membrane on different supports was studied. Four kinds of tea aroma components,called the cis-3-hexenol,linalool,trans-2-hexenal,and benzyl alcohol,were chosen as representatives. The effects of operating conditions on the pervaporation performances of each aroma component from four ones and their mixture were investigated. Results showed that pervaporation membrane had high separation factor for all of four tea aroma components in the single component system.With the increase of the component concentration,the separation factor of aroma decreased. The separation factor of aroma would firstly be increased and then decreased with the increase of the temperature. In conditions of 0. 01% and 30 ℃,the separation factor of cis-3-hexenol,linalool,trans-2-hexenal and benzyl alcohol were 64. 49,31. 45,29. 31,and 28. 87,respectively. In the mixed system,the separation factor was decreased. The PDMS / PVDF membrane had higher separation factor and higher aroma flux than PDMS / Al2O3 membrane.