摘要
莱鲍迪苷A是极为重要的新型甜味剂,由于缺乏合理的溶解度数据且其成核机理不明确,导致现存的结晶工艺得到的结晶产品存在细晶多、粒度分布不均等问题。为此,首先利用激光动态法测定了莱鲍迪苷A在甲醇-水、乙醇-水、正丙醇-水、丙酮-水中的溶解度及在甲醇-水中的介稳区宽度,并利用Wilson方程对溶解度进行模型验证;研究了溶剂组成、饱和温度、搅拌速率与冷却速率对介稳区宽度的影响,研究表明,莱鲍迪苷A的介稳区宽度随溶剂中甲醇含量与冷却速率的增加而变宽,随饱和温度与搅拌速率的增加而变窄;基于经典成核理论与相关模型,计算了莱鲍迪苷A的固液界面能γ与临界Gibbs自由能ΔGcrit等成核参数;根据表观成核级数m分析可知,初始温度高于318.15 K时,连续成核是莱鲍迪苷A主导的成核方式;基于上述研究优化了莱鲍迪苷A冷却结晶过程,得到了粒度分布均一的结晶产品。
Rebaudioside A is an extremely important new sweetener.Nevertheless,there are some quality problems of its crystal products obtained by existing crystallization process such as too many fine crystals and large crystal size distribution.In order to solve the above problems,a comprehensive study about crystallization of rebaudioside A was carried out.Firstly,the solubility of rebaudioside A in several binary mixed solvents including methanol water,ethanol-water,n-propanol-water and acetone-water as well as the metastable zone width in methanol-water mixed solvents were determined by means of laser dynamic technology and the experimental solubility data was verified by Wilson model subsequently.Besides,the influences of solvent composition,agitation rate and cooling rate on metastable zone width were explored and the result showed that the metastable zone width would increase with the increment of the content of methanol in mixed solvents or the increment of cooling rate while would become narrow with the incensement of initial saturation temperature and stirring rate.In addition,on the basis of the classical nucleation theory and corresponding metastable zone model,the nucleation parameters such as interfacial energy between solid and liquidγand critical Gibbs free energyΔGcrit of rebaudioside A were calculated.Furthermore,according to the calculated value of apparent nucleation order m,progressive nucleation was the dominant nucleation mechanism of rebaudioside A when the initial crystallization temperature was higher than 318.15 K.At last,the crystallization process was optimized and the high quality rebaudioside A product with uniform particle size was obtained.
作者
郭盛争
吴送姑
苏鑫
高伟
牛志平
龚俊波
GUO Shengzheng;WU Songgu;SU Xin;GAO Wei;NIU Zhiping;GONG Junbo(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China;Chenguang Biotech Group Incorporated Company,Handan 057250,Hebei,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2021年第8期3997-4008,共12页
CIESC Journal
基金
国家自然科学基金项目(91634117)
京津重大科技成果转化专项基金项目(19047144Z)。
关键词
莱鲍迪苷A
溶解度
介稳区宽度
成核
粒度分布
rebaudioside A
solubility
metastable zone width
nucleation
particle size distribution
