膜系统加工冷溶型去苦味速溶绿茶研究

在研究证实速溶绿茶中简单儿茶素与酯型儿茶素的比值为0.5以上时可达到去苦味特性的基础上,试验采用中试设备,对不同截留分子量的超滤膜超滤蒸青绿茶微滤液的超滤效果和不同浓缩方法的浓缩效果进行了系统的比较研究。结果表明,在35℃、1.74Mpa条件下,采用3500Da膜超滤绿茶微滤液,且在滤液重量接近粗滤液重80%时,以10%粗滤液重纯净水透析两次,滤析混合液中的简单儿茶素与酯型儿茶素的比值可达0.53,简单儿茶素、酯型儿茶素、EGCG、总儿茶素的得率分别达到57.00%、20.00%、20.00%、30.00%,含量分别达到14.47%、12.78%、8.34%、26.32%,产品呈现无苦味特性。在35℃、2.4Mpa条件下,采用300Da纳滤膜对超滤滤析混合液进行浓缩,工效高,产品0.45g兑140ml4℃冷水,20s内溶解,且品质成分损失很少。

Study on Processing of Cold Soluble De-bitter Instant Green Tea by Membrane System

Based on the researched fact that if the ratio of simple catechin /estered catechin is more than 0.5, the instant green tea has no bitter taste, the ultra-filtration and concentration tests for the micro-filtrated steamed green tea liquid by pilot instruments were carried out in order to process the cold soluble de-bitter instant green tea .The result showed that under the conditions of 35℃, 1.74 Mpa and 2 times dialysis while the ultra-filtrated liquor was 80% of the original liquor and the weight of each dialytic water is 10% of the original liquor, the rate of simple catechin /estered catechin in the mixed liquid of 3500 Da ultra-filtrated liquid and dialysed liquid could reach 0.53, the yield rate of simple catechins, estered catechins, EGCG, and total catechins reached 57.00%, 20.00%, 20.00% and 30.0%, respectively, whose content was 14.47%, 12.78%, 8.34% and 26.32% respectively, and the instant green tea product had no bitter taste. The concentration method of 300 Da nano-filtration for the mixed liquid under the conditions of 35℃, 2.4 Mpa showed the best work efficiency, the product 0.45g could easily dissolved in 140 ml 4 ℃water within 20 second ,and the quality component losed little .