Microfiltration + ultrafiltration + nanofiltration membrane PK traditional stevia production process

　　Stevia, also known as steviol glycosides, is a glycoside extracted from stevia leaves. Stevia is native to Paraguay and Brazil. It has the characteristics of high sweetness and low thermal energy. The sweetness is 200-300 times that of sucrose, and the calories are only 1/300 of sucrose. As the world's third-generation sugar source, stevia has been recognized as a promising high-sweetening sweetener. The extraction and production methods of stevia are diverse, and the problem that follows is the improvement of the quality of stevia. At present, China's stevia extraction industry is facing the dilemma that the overall level of stevia production quality is not high. The rapid development and maturity of membrane technology make membrane separation, membrane concentration, and membrane decolorization an indispensable part of the plant extraction process, including the extraction and concentration of sweet leaf sugar.

　　Disadvantages of traditional processes

　　1, in the extraction process, stevia needs a lot of water and a lot of time. Due to the long use of stevia, in order to avoid the deterioration of raw materials and reduce the loss of some stevia, a large number of toxic preservatives will be added. Greatly affects the quality of the product.

　　2. In the process of plate and frame filtration, a certain amount of flocculant needs to be added to the material for processing, but the impurities after flocculation contain a certain amount of steviol glycosides, which will reduce the yield. At the same time, due to the limitations of the production environment, the plate and frame filter press is difficult to meet the production requirements of food additives.

　　3. Due to the characteristics of activated carbon, the decolorization process of activated carbon after flocculation will also take away some of the products, thereby reducing the yield.

　　4. In the process of powder spraying and drying, stevia liquid directly enters the drying and powder spraying process after being treated by ion exchange resin, so the dosage is particularly large, the concentration is very low, resulting in a large amount of heat source consumption, increasing the economic burden of the entire enterprise.

　　Advantages of microfiltration + ultrafiltration + nanofiltration membrane system

　　1. The composite membrane system (ceramic microfiltration + organic separation + nanofiltration concentration) is used to remove a large number of impurities in the whole process, including macromolecular tannins, proteins and some small molecular impurities, and the removal accuracy is higher, and the stevia content is greatly increased.

　　2. The nanofiltration membrane system in front of the resin system effectively concentrates the stevia solution, reduces the use of resin, effectively reduces the solution required for regenerative resin, reduces wastewater discharge, and protects the environment.

　　3. The concentrated film system before powder spraying is used to recover the solvent of the integrated resin system and concentrate the stevia liquid to reduce evaporation.

　　4, no add preservatives and flocculants, fully meet the production requirements of food additives.

　　5. Design online regeneration cleaning and sewage device to reduce labor intensity and production costs and improve production efficiency.

　　6, at room temperature for normal treatment, without any phase change, to ensure that the nature of the stevia solution will not change.

　　7. Low energy consumption and low operating cost.

　　8. High degree of automation, convenient operation and maintenance.

　　The nanofiltration membrane (www.nalvmo.cn) separation process is a purely physical process that can be operated at room temperature without phase transitions. There is no adverse effect on the active ingredient in the material, and the active ingredient content of the product is high. Concentration and separation are carried out simultaneously, without adding other substances or changing the properties of the separated substances. It has the characteristics of strong adaptability, stable operation, energy saving, small size and separable. Membrane element performance can be restored by cleaning, reducing system operating costs. Membrane separation processes can improve product yields, reduce investment scale and operating costs. At present, nanofiltration membrane technology has been widely used in milk degreasing, rice wine purification, monosodium glutamate purification, sucrose decolorization, juice concentration, beer sterilization and other industrial production.