Marques Marisa P, Alves Vítor D, Coelhoso Isabel M
LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica 2829-516, Portugal.
LEAF-Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, Lisboa 1349-017, Portugal.
Membranes (Basel). 2016 Dec 28;7(1):1. doi: 10.3390/membranes7010001.
In this work, the concentration process of three different tea extracts (medicinal Rosil No. 6, Black, and Forest Fruit teas) using the osmotic evaporation (OE) process, was studied. The effect of the OE process on the content of phenolic compounds and antioxidant activity was evaluated. The concentration process was carried out in a hollow-fibre membrane contactor with an effective surface area of 0.54 m². The tea extract was circulated through the shell side of the contactor, while a concentrated osmotic solution (CaCl₂ 5 M) was circulated inside the fibres. The flux, the driving force, and the mass transfer coefficient were evaluated. A decrease of the water flux over time was observed and was attributed only to the decrease of the driving force, caused by the dilution of the osmotic solution. Using a surface area/feed volume ratio of 774 m²·m, it is possible to reach a tea concentration of 40% (/) in 5 h, with a constant water flux and without losing the phenolic content and antioxidant potential in most teas.
在这项工作中，研究了采用渗透蒸发（OE）工艺对三种不同茶提取物（药用玫瑰6号茶、红茶和森林水果茶）进行浓缩的过程。评估了OE工艺对酚类化合物含量和抗氧化活性的影响。浓缩过程在有效表面积为0.54平方米的中空纤维膜接触器中进行。茶提取物在接触器的壳侧循环，而浓缩的渗透溶液（5M氯化钙）在纤维内部循环。评估了通量、驱动力和传质系数。观察到水通量随时间下降，这仅归因于渗透溶液稀释导致的驱动力下降。使用774平方米·立方米的表面积/进料体积比，在5小时内可以达到40%（/）的茶浓度，水通量恒定，且大多数茶不会损失酚类含量和抗氧化潜力。
