Rebaudioside A, or Reb A, is a high-intensity sweetener that contains no calories. It is valued for its sweetness, which can be 250 to 450 times that of regular table sugar, or sucrose. This potency allows it to be used in very small amounts to achieve a desired level of sweetness in food and beverage products. It is widely used in the food industry to reduce or replace sugar in various commercial goods.
Origin and Extraction Process
Rebaudioside A is a naturally occurring compound derived from the leaves of the Stevia rebaudiana plant, which is native to South America. This molecule is one of several sweet-tasting components found in the plant, which are collectively known as steviol glycosides. The leaves of the stevia plant have been used for centuries as a natural sweetener.
The process to obtain Reb A begins with harvesting and drying the stevia leaves. These leaves are then steeped in hot water, much like brewing tea, to draw out the sweet compounds into a liquid extract. This initial extract contains a mixture of different steviol glycosides, plant matter, and other substances.
To isolate Rebaudioside A, the liquid undergoes a multi-step purification process. It is filtered to remove solid plant materials, and techniques like chromatography are used to separate the steviol glycosides from other components. The purified extract is then treated with alcohol, where crystallization helps to separate and concentrate Reb A from other glycosides. This refining process results in a high-purity powder, often 95% concentration or higher.
Distinguishing Rebaudioside A from Stevia
Confusion often exists between the terms “stevia” and “Rebaudioside A.” The term “stevia” is used broadly to refer to anything derived from the plant, including unprocessed leaves or crude extracts. These forms contain a mixture of all the compounds present in the leaf, each with a different taste profile.
Rebaudioside A is a specific, highly refined steviol glycoside. While the stevia leaf contains multiple steviol glycosides, Reb A and stevioside are the most prevalent. Reb A is often preferred commercially because it has a less bitter aftertaste compared to stevioside.
High-purity Reb A is what is found in sweetener products on grocery store shelves, often blended with other ingredients like erythritol or dextrose. The food industry is also exploring other purified steviol glycosides, such as Rebaudioside M (Reb M). Reb M is reported to have a taste profile even more similar to sugar with less bitterness than Reb A.
Safety and Regulatory Status
High-purity Rebaudioside A has been reviewed by major regulatory bodies. In the United States, the Food and Drug Administration (FDA) has designated high-purity steviol glycosides (at least 95% pure) as “Generally Recognized As Safe” (GRAS). Since 2008, it can be legally used as a general-purpose sweetener in a wide range of foods and beverages.
This GRAS status applies specifically to these refined extracts and not to whole-leaf or crude stevia extracts. The FDA has not approved whole-leaf or crude stevia as food additives, citing a lack of sufficient safety information. Concerns have been raised that raw stevia might affect the kidneys or cardiovascular system.
Health authorities have established an Acceptable Daily Intake (ADI) for guidance. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has set an ADI for steviol glycosides at 4 milligrams per kilogram of body weight per day, expressed as steviol equivalents. This measure helps ensure that consumption remains within a safe range.
Taste Profile and Common Uses
Rebaudioside A is characterized by its clean, sweet taste. However, it can have a slightly bitter or licorice-like aftertaste, especially at high concentrations. Individual sensitivity to this aftertaste can vary, and its intensity often depends on the specific food or beverage application.
Due to its properties, Reb A is incorporated into a vast array of consumer products. It is commonly found in diet sodas, flavored waters, and other reduced-calorie beverages. It is also in dairy products like yogurts and ice creams, as well as in tabletop sweetener packets. Other uses include sugar-free jams, confections, and baked goods.