The stevia plant (Stevia rebaudiana), also known as sweetleaf or sugarleaf, is a small shrub from South America. It represents a healthy, natural and calorie-free alternative to sugar and sweeteners. In Japan it has long-since conquered the market for sweetener.

Plant

The plant's origin lies in Paraguay, South America, where it has been used by the natives for centuries for sweetening and medicinal purposes. Stevia is an annual plant, is not frost resistant and can grow up to a meter in height. The self-sterile plant is pollinated through the wind and has white flowers. Its leaves are up to three centimeters in length and are used in dried form as a sweetener for tea.

Contents

Over 100 plant-based active agents have been identified in the stevia plant, most of which are among the groups of terpenes and flavonoids. However, various glycosides are responsible for the sweetness. In addition to stevioside and rebaudioside A (which are covered in greater detail below), the leaves also contain steviol, rebaudioside C, D, E, F and ducloside A.

Tab. 1 Steviol Glycosides with the appropriate chemical remains by Geuns

Stevioside makes up the largest part of the sweetening properties in the leaves. Since they are more heat resistant than other sweeteners, they are more suitable for cooking and baking. Rebaudioside A is one of the deciding ingredients, when it comes to the quality of the sweetness. The more rebaudioside a product contains, the better and more expensive the product (the more intense the sweetness, the less bitter the taste - see table 2). It is of particular importance that stevioside is 300 times sweeter than sugar. Therefore, stevioside should be used with caution. It is easy to use too much and fail to reach a desired level of sweetness. This can leave an unpleasant aftertaste.

Stevia as a Sweetener

Sweetening with stevia is not as easy as it seems. As discussed earlier, stevioside has differing levels of quality. The poorer the quality, the stronger and more pronounced the bitter aftertaste. This flavor, if it is perceived by humans, is described not only as bitter, but also as medicinal, metallic or artificial. However, these negative impressions can be kept to a minimum by using the optimal dosage. There are also differences in the perception of the sweetness. Certain people who generally prefer less sweetness describe the intensity of the sweetness as very high. With the stevia sweetener, it is essential to use a smaller amount than when using sugar.(compare Tab. 3)

To achieve the best results, stevia sweetener should be used in combination with sugar. It tastes best, when it is used with about 4/5 of the necessary sugar; therefore, a small proportion of sugar should be maintained.

Health/Legal Basis

Sweeteners in our food are here to stay, but sugar's connection to so-called diseases of affluence has caused consumers to be more wary of eating too much sugar. Accordingly, sugar substitutes are in demand and stevia offers a natural alternative. Sugar substitutes have long been used in diet products, particularly in those for diabetics.

In addition, stevia does not cause cavities and can also even prevent cavities, as proven in a 2006 school project at the HFLS Ursprung (see http://stevia.ursprung.at). Stevia is reputed to have many other positive influences on our health, most of which have yet to be scientifically proven. According to the following paragraph from the EFSA (European Food Safety Authority), stevia is not harmful to human health:

"Toxicological testing showed that the substances are neither genotoxic, nor carcinogenic, or linked to any adverse effects on the reproductive human system or for the developing child. The Panel set an Acceptable Daily Intake (ADI)[1] of 4 mg per kg body weight per day for steviol glycosides, a level consistent with that already established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA)." (http://www.efsa.europa.eu/de/press/news/ans100414.htm).

It is worth mentioning that the 4 mg per kg of body weight mentioned in the paragraph above would substitute the entire recommended Acceptable Daily intake for sugar.

Due to the JECFA recommendation, stevia is expected to be approved in the EU food market shortly. In many non-EU countries, the approval is as good as done. Interestingly, stevia has been approved for use in Japan since 1970; Australia and New Zealand followed in 2008.

Tab. 2 Intensity of sweetness of Stevia in comparison with sugar and the relationship of sweetness to bitterness

Tab. 3 Intensity of sweetness of Stevioside in various concentrations in relation to sugar