Tate & Lyle, along with its stevia supply partner Sweet Green Fields, has entered a collaboration with the non-profit environmental organisation Earthwatch to assess the sustainability of its stevia supply chain. Much of the world’s stevia, including that from Sweet Green Fields, is cultivated in China, and under the new agreement, independent researchers from Earthwatch intend to survey farms there. They will ensure sustainable practices are consistently implemented, and that farmers benefit as much as possible from socio-economic gains, from seedling producers to family-run and industrial-scale farms.

Stevia suppliers have long publicised the plant for its low water use and low use of land compared to other natural sweeteners, including sugar. While water is a major agricultural input for stevia plants, their intense sweetness means their in-product water and land footprint is much lower than it is for traditional and bulk sweeteners.

PureCircle aimed to take this a step further when it introduced its StarLeaf stevia variety in 2017 with significantly higher levels of steviol glycosides, the plants’ valuable sweet components. The company suggested that greater sustainability could be a major advantage, because its aim to produce 20 times the steviol glycosides on the same amount of land could make a significant difference to the crop’s land and water use. 

Manufacturers’ main considerations when using stevia tend to be price and taste, and suppliers including Layn Corp. and PureCircle are among those looking to improve their stevia plants to contain more of the best-tasting steviol glycosides. Some of these molecules, such as Reb D and Reb M, only exist at very low concentrations in the stevia leaf, meaning they have a higher cost than more abundant molecules like Reb A. If stevia plants naturally contain more Reb D and Reb M, this can help bring costs down.

Alongside taste and price, concern for naturalness also seems to be on the rise, as evidenced by the fact that product launches sweetened with stevia outstripped those sweetened with aspartame for the first time in 2017. According to Innova Market Insights, stevia featured in 27% of new products containing high intensity sweeteners in 2017, while 22% contained aspartame. 

As more consumers look to cut their sugar intake for health reasons and stevia gains in popularity, concern about the broader impacts of the crop is likely to come to the fore. And large companies like Tate & Lyle are aware that they will come under scrutiny as they use greater quantities of stevia as a replacement for sugar.