Study Of Stevioside And Its Manufacturing Technique

Stevioside, composed of 8 kinds of diterpenoid glycoside is the extraction of dry leaves of stevia rebaudiana which belongs to Compositae herb.Stevioside serves as a brand new Sweetener, a perfect substitute of sucrose, which becomes more and more popular in the market of sugar for the reason that it has high level of sweetness, and low level of calorie, and also nonpoisonous. The production of stevioside in our country can satisfy the demands of sugar that required by global market which can serve as the sweetener instead of artificial sweetener, which is harmful to the health of Human. Meanwhile, the physical and chemical properties of stevioside remain stable and also no fermentability, no metabolic that make it a perfect consumption for those who has hypertension, diabetes, obesity, caries. And also people woill not get fat through long-time consumption. In this thesis, we introduce a method of extraction, separation, refining the stevioside in order to provide a technical support for the fabrication of the refined production which has a high level of stevioside.The normal way of extraction of stevioside are stafaming, cold water soaking,enzymatic hydrolysis. The optimal way is enzymatic hydrolysis through improving the technological condition of the three ways, comparing the extraction rate. The optimized technological condition of enzymatic hydrolysis is: using cellulase, temperature of 45℃, pH 5, the dosage of enzyme is 5%, extraction time is 100 minutes.,The industrial separation technology of stevioside is as follows, removing impurity by adding flocculant to the feed solution. Optimizing inorganic salts flocculant and the flocculanting condition after adding high polymer flocculant A new high efficient organic polymer flocculant was abtained which is composed of Fecl3, CaO and PAM. The optimized flocculanting condition is as follows, flocculant ratio is Fecl3: CaO :PAM = 1:2.5:0.05, at pH 9, and remain in hot water bath for 30 minutesThe purification precess of stevioside is as follows, refined through adsorption and decoloration by resin, decoloration by CL ion exchange fiber, after the absorption by macroporous adsorption resin, washing by acid and alkali, desorption agent was 95% ethanol. The maximal absorption of macroporous adsorption resin by dynamic absorption can be reached when the pH is between 9 and 10, adsorption velocity is 2 BV/h. At the same time, the desorption can be completed by the velocity is 2 BV when desorption agent was 70% ethanol, the velocity is 1 BV/h. the optimized technological condition of refined acid elution is as follows, the concentration of acid(HCl) is 5%, absorption velocity is 1BV/h, the dosage of acid is 2BV. And the optimized technological condition of refined alkali elution is as follows, The concentration of alkali ( NaOH) is 3%, the velocity is 1BV/h , the dosage of alkali is between 2 BV.