Rebaudioside A, or Reb A as it is called, is recognized as the sweetest component of the Stevia leaf, which is used in the making of commercial Stevia products. It is between 200 and 400 times sweeter than sugar and has the added benefit of being non-caloric. Two sweet compounds have been found in the Stevia Rebaudiana Bertoni plant and they are Stevioside and Rebaudioside. Reb A is the sweeter of the two.
Extracting Reb A from Stevia
In order to extract Reb A from the Stevia leaf, the leaves are processed in water in a process very similar to making tea. This unleashes the natural sweetening compounds that are found in the leaves. The next step is purification of the “tea” through filtration, much like you could do at home. This takes out any impurities and leaves only the pure Reb A. This solution may be blended with other components in order to create a final product or may be marketed in liquid or powder form.
There are some products on the market that are 99.5% pure Reb A. It is very sweet and has no bitter taste. If you happen to be using a product with higher levels of steviosides, it will usually not have as much Reb A. In all likelihood, the bitterness will still be present. Pure Reb A has been extracted from the Stevia plant with no chemical modifications or enzymatic modifications of the glycosides, which may lead to bitterness. Specific plants have also been bred to make more overall glycoside and consequently more Reb A.
Processing Reb A
In order to process Reb A, there are 5 major steps:
- Water extraction is done by placing dried Stevia plant leaves in warm water until the glycosides dissolve.
- The sweet juice from the leaf is squeezed out of it.
- Filtration occurs with a very fine sieve in order to remove organic matter from the sweet water.
- More filtration and extraction, often using proprietary methods, are done in order to isolate the glycosides that are desired.
- The final product is spray dried in order to help evaporate water that was used in the extraction process.
No additional processing is done to change the color, flavor or appearance of the final product. There are also no modifications done to the glycosides.
Why does Reb A taste so good?
Reb A tastes better than many other Stevia products for a variety of reasons. Although primarily because the compound Stevioside, that causes the bitter taste in other extracts, is almost completely removed. This is how a 99.5% pure product can be achieved. Most Stevia products have Reb A of 20% to 70% only, even though they state they have 90% or more Stevia in them. The remainder of the product content is Stevioside which contains that less desirable bitter taste.