大孔树脂D392对莱鲍迪苷A和甜菊苷吸附作用的研究
Study on adsorption effect of rebaudioside A and stevioside onto D392 macroporous resin
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摘要: 根据莱鲍迪苷A(RA)比甜菊苷(S)多一个葡萄糖基的特点,针对性地选择了14种工业树脂,分别考察了它们对RA和S的吸附能力和吸附选择性。在此基础上,研究了吸附选择性较高的大孔树脂D392的吸附动力学和吸附热力学,并考察了温度、甜菊糖苷水溶液浓度、pH、溶剂对D392吸附选择性的影响规律。结果表明,D392在水相中对S的吸附能力大于对RA的吸附能力,吸附为放热过程,且在较低温度下吸附选择性较好。在298.15K,pH7.0,混合糖苷(RA/S=1∶1)浓度为5g/L时,经D392吸附6h,吸附残液中RA/S达到最大值。进一步以RA含量70.3%的甜菊糖苷作供试液,经D392吸附6h,吸附残液中RA含量可提高到88.4%,RA保留率为68.0%。Abstract: Based on the difference of molecular structure between rebaudioside A and other steviol glycosides, the performance and separation characteristics of fourteen selected commercial adsorbent resins for the separation and purification of RA had been evaluated. According to the results, D392 offered higher adsorption selectivity than other resins. Influential factors such as adsorption kinetics, adsorption isotherm, temperature, concentration and pH value of adsorption solution, and solvents to the adsorption selectivity were successively investigated on D392. The results showed that the ability of adsorption of S with D392 was stronger than that of RA. The adsorption process was exothermic in aqueous solution, and higher adsorption selectivity was found at lower temperatures. The RA/S ratio of the raffinate attained the maximum when the adsorption was conducted at 298. 15K, pH 7. 0, and 5g/L of the feeding solution (RA/S=1∶ 1) . After the treatment on D392, the content of RA in the product increased from 70. 3% to 88. 4%, and the recovery yield of RA was 68. 0%.