超滤技术在乌龙茶饮料澄清中的应用

利用平板膜超滤设备．选择ＰＥＫ—１００，ＰＥＫ一２００．ＰＥＫ—７００三种不同截留分子量的聚醚酮材料膜，处理经一定条件提取的乌龙茶汁．结果表明，超滤可以有效地澄清茶汁，而不带入任何化学物质．选择截留分子量为７万的ＰＥＫ—７００膜最为理想，能够去除茶汁中７６．ｌ％的蛋白质，８５．ｌ％的果胶，６７．４％的可溶性淀粉，澄清度提高到８８．３％，而茶汁中的有效风味物质茶多酚、咖啡碱只减少１０％以内．从减少小膜阻力、凝胶层阻力和浓差极化现象方面考虑，ＰＥＫ—７００膜也明显优于ＰＥＫ—１００、ＰＥＫ—２００膜．

Clarification of Oolong Tea Beverage by Ultrafitration

The oolong tea juice extracted in the fixed factor was ultrafiltrated by using the plate-frame module and choicing three kinds of PEK membrane with three pore diameter distrobitom(PEK-100, PEK-200, PEK-700).The results indicated that ultrafiltration can clarificate the tea juice effectively and close not carry and chemical matter into tea juice.The PEK-700 membrane is more excellent than other two membrane.It can obstruct the 76.0%protein, 85.1 % pectin,67.4 % dissolved starch of the tea juice and the clarification degree of the tea juice can be increased to 88.3%.The testeable matters of the tea juice polyphenols and coffeine are obstrusted fewer than 10%.In addition,PEK-700 membrane is better than PEK-100, PEK-200 membranes in reducing membrane drag and coagel dreg drag.