茶渣对儿茶素的吸附动力学  

Adsorption kinetics of tea waste to catechins.

作　　者：胡书琴[1] 汤一[1] 刘莉[1] 

机构地区：[1]浙江大学农业与生物技术学院茶学系,杭州310058

出　　处：《浙江大学学报（农业与生命科学版）》2014年第6期679-687,共9页Journal of Zhejiang University:Agriculture and Life Sciences

基　　金：国家茶叶产业技术体系经费资助(CARS-23)

摘　　要：以茶渣为吸附剂,分别用拟一级动力学方程和拟二级动力学方程对其选择性吸附过程进行拟合,探讨茶渣分别对以表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)为主的儿茶素组分、咖啡碱的吸附和解吸附动力学特性.结果发现:拟二级动力学模型能更好地描述该吸附过程;吸附后茶汤中咖啡碱与总儿茶素比值由原来的0.164降至0.079;经40%乙醇解吸后,所得解吸液中酯型儿茶素占原溶液中酯型儿茶素的86.99%,咖啡碱为24.24%;茶渣柱层析穿透实验表明,咖啡碱最早穿透,其次为简单儿茶素,酯型儿茶素穿透最晚,进一步证明茶渣对以EGCG为主的酯型儿茶素吸附作用最强,脱咖啡碱效果显著;解吸实验表明,40%乙醇可充分解吸茶渣所吸附的酯型儿茶素.因此,在本实验条件下,解吸附可先用10%乙醇淋洗出咖啡碱,再用40%乙醇洗脱酯型儿茶素,可望得到富含酯型儿茶素的高纯度儿茶素类产品.Summary Catechins, the main functional components in tea, were generally recognized as possessing desirable biological and physiological effects, such as anti-oxidation, anti-cancer, reducing the risk of cardiovascular diseases etc. Therefore, application areas of tea catechins in food and pharmaceuticals were expanding rapidly. At present, conventional extraction technologies of catechins contained hot water extraction method, organic solvent extraction process, resin extraction method and supercritical CO2 extraction method. However, the application value was limited because of the low efficiency, high cost and potentially toxic residues. In order to extract cateehins efficiently and safely, the recent studies found that lignocellulose could absorb catechins in abundance and in a low cost. Tea waste was used as a new kind of adsorbent in this paper. Because of the porous structure, it had large specific surface area. Meanwhile, the main components of tea waste were cellulose and protein. They all contained a mass of carboxyl groups and hydroxyl radicals which could form hydrogen bonds with catechins. The tea waste was similar to lignocellulose in structure and it was eatable, safe with no poisonous residue. The experiments were carried out as below. The equations of pseudo-first-order model and pseudo-second- order model were used to simulate the adsorption kinetics respectively. Then, different concentrations of ethanol were used to desorb the tea waste when it reached adsorption saturation. Finally, the same size tea waste was used to pack the chromatography column and the breakthrough curves of catechins and caffeine were drawn, then different concentrations of ethanol were used to elute the column gradely when it reached adsorption equilibrium. The results indicated that the kinetics were more fitted to the pseudo-second-order model （R2 = 0. 913 6 -0. 997 1）. The order of the secondary adsorption speed constant k2 was epigalloeatechin gallate （EGCG） （0. 000 5 g/（mg - min） 〈 gallocatechin �

关 键 词：茶渣 吸附动力学 儿茶素 选择性吸附 

分 类 号：TS272[农业科学—茶叶生产加工] S571.1[轻工技术与工程—农产品加工及贮藏工程]