With the approval of Stevia in the United States, a major consumer of sweeteners, its demand will grow at a rate of 30% per year. Stevia Extract Powder is a natural, high-intensity, low-calorie sweetener extracted and refined from the leaves and rhizomes. It is mainly composed of two components, Stevioside (ST) and Rebaudioside A (RA). RA is an ideal substitute for sucrose. Below is an overview of how is stevia extract made.
How To Make Stevia Extract?
The preparation process of Stevia is mainly as follows: drying and crushing leaves → liquid phase extraction → impurity removal → resin treatment → spray drying and refining. Here are the details of the key steps:
1. Extraction:
The content of ST and RA in the stevia leaves at the early bud stage is the highest. After drying and pulverizing the stevia leaves in this period, the stevia sugar is usually extracted in a liquid phase with a polar solvent such as hot water or alcohol. The extraction method is usually divided into tank batch extraction or countercurrent continuous extraction.
2. Isolation and purification:
Stevia stock solution contains a lot of impurities such as protein, organic acid, tannin, saponin, pigment, inorganic salt and so on. The content of these impurities is 5-7 times that of glycosides. Column chromatography or membrane filtration is commonly used to separate and purify from stevia stock solution.
3. Resin Treatment
When membrane filtration is used to separate and purify, Stevia can be removed by filtration through ceramic micropores, ultrafiltration membranes, and nanofiltration membranes.
Ionic compounds in liquid and organic molecules whose molecular weights are quite different from those of Stevia. A stevia-enriched solution is obtained.
4. Spray drying:
The concentrated liquid can be obtained by cooling crystallization, concentrating crystallization or spray drying to obtain crude Stevia whose main components are ST and RA. The product is dark in color. It can be decolorized with activated carbon before crystallization or spray drying to give a white product. Most stevia extract manufacturers produce such products.
5. Refined:
The solubility of ST and RA in hydrophilic solvents is different. To achieve a saturated concentration, the crude stevioside was dissolved in methanol, ethanol, and other solvents. Then, ST or RA crystals are selectively precipitated by methods such as concentration and cooling. To ensure that high-purity RA can be obtained, the crystals can be re-dissolved in ethanol aqueous solution to remove insoluble impurities, and the products can be obtained by spray drying or concentrated crystallization.
Summary
Stevia is in line with today's consumption concept of "natural, green, safe, and healthy". At present, the investment in Stevia by the world's top 500 companies such as Coca-Cola, Cargill, and PepsiCo on a global scale will greatly promote the development of the stevia industry. As the most promising substitute for sucrose, Stevia Extract Powder will be further recognized by the market.