Stevia Article Series

What Are the Different Forms of Stevia Available?

Monday, 09 July 2012

Stevia is a versatile natural sweetener and is commercially available in four main forms: leaf powder, dried or fresh leaves, liquid extract and powdered form (usually white unless blended with colored additives).

Stevia leaves: This is obviously stevia in its most natural state. Although not the sweetest form of the plant it is definitely the ‘greenest’ with the least impact on the environment. Fresh stevia leaves are unprocessed and can be difficult to source. The most prominent steviol glycosides in dried leaves are stevioside and rebaudioside A, amounts present are, on a dry weight basis, approx. 4 - 13% and 2 – 4% respectively, although new varieties that yield higher amounts are constantly being developed. Typical uses of stevia leaves are: fresh – oral ingestion for its sweet properties and some medicinal purposes, dried – brewing as a herbal tea, as a tea blend as a base for the extraction of steviol glycosides.

Stevia leaf powder: This ground, dried stevia leaf has similar properties to the dried stevia leaf itself. It is a non-dissolving product that can be used in cooking and baking and to sweeten hot or cold beverages.

Liquid Stevia extracts: These contain the leaf-extracted steviol glycosides, the extraction process initially concentrates the glycosides which are then diluted with a base of usually just water forming a dark liquid. Further processing produces a clear form of the liquid which can include glycerine and/or alcohol as its base. In addition to these ‘natural’ flavored liquids additional flavorings can also be incorporated into the product.

Powdered ‘pure’ Stevia extracts: We tend to define ‘Pure Stevia Extracts’ as a product which contains only processed steviol glycosides – with no additives whatsoever, except perhaps water. The two most prominent glycosides of the stevia plant having the sweetest properties are stevioside and rebaudioside A (reb. A). The quality of taste of stevia extracts is determined by the ratio of stevioside to reb. A. If stevioside makes up more than 50% of the total glycosides, there tends to be a ‘liquorice’ after-taste present. Where reb. A makes up more than 50% then there is an improvement in taste. There may also be a small percentage of other steviol glycosides present (less than 5%) such as; rebaudioside B, D, E and F, dulcoside B and steviolbioside. Needless to say, products with a high concentration of reb. A are at the premium end of the market, indeed certain countries specify a minimum reb. A content in marketable products.

Stevia blends: Comprises the widest range of products available, by far. Stevia blends products consist of one or more steviol glycosides blended with other ingredients to alter or enhance taste, flavor, texture, form or behaviour of the final product. Examples of such blends are: ‘stevia baking blend’, flavored liquid drops and tea blends. As the stevia component of a product lessens there is a point at which it ceases to be a stevia product and becomes a product that uses stevia. The list of products in the latter category is growing markedly, such examples are: soft drinks, lip balm, protein powders, confectionery, toothpaste, sauces ...