Patenting Stevia
Patent protection for stevia is a fast-moving area of IP which requires careful consideration of the use of data

Products that are low in sugar and formulated from natural ingredients are growing increasingly desirable to consumers. Refined sugar has long been linked to obesity, type 2 diabetes, and a host of other illnesses. Artificial sweeteners, while low-calorie, have also been associated with a wide range of health issues, leading to some consumer concern. Natural sugar alternatives, on the other hand, can deliver low-calorie sweetness without these negative side effects and may provide potential health benefits in the form of lowered blood sugar and insulin levels.

Natural low-calorie sweeteners can be extracted from the stevia plant (Stevia rebaudiana). The sweetening compounds include stevioside and rebaudioside A, and are typically collectively termed “stevia”.  According to a report by Fortune Business Insights, the sugar substitutes market is predicted to reach $10.27 billion by the end of 2026 and natural sweeteners such as stevia are taking an increasing share of this huge market. In view of this, it is not surprising that innovators have been filing increasing numbers of patent applications relating to stevia. As shown in the figure below, there has been an increase in the number of PCT applications related to stevia in food products, from 15‑20 per year in the early 2000s to 70+ by the mid-2010s.

Source: Questel Orbit search for PCT applications in IPC classes A21 or A23 with the terms stevia, stevio*, or rebaudio* in the claims

This increase in patent applications has been led by the established names in the food industry, with Coca-Cola, PepsiCo, and Mondelez amongst the top 10 by number of applications. However, the number 1 applicant is a relatively new entrant to the market, PureCircle, founded in 2001 and specialising in stevia products. Clearly, IP is exceptionally important in this growing area, both for the established names to take advantage of the new market, and for the new-comers to carve out and protect a niche for themselves while gaining consumer recognition.

One issue related to gaining patent protection for stevia products is that the sweetening compounds themselves are long known. Therefore, patent applications in this area typically focus on novel applications of these compounds, e.g. in combination with other ingredients as part of specific food products, rather than attempting to gain protection for the compounds per se.

While there is usually plenty of room to establish a novel claim including stevia compounds, establishing an inventive step can be less straightforward. Since the stevia compounds themselves are known for their sweetening properties, a patent examiner might object that a new use of stevia is merely an obvious use of a known sweetener, and thus lacking an inventive step. One strategy for addressing this problem is to provide data demonstrating that the new use of stevia provides some unexpected advantage or improvement. For instance, an innovator may find that a certain combination of stevia and other ingredients may be used to replace sugar, while providing a product with equivalent taste and mouthfeel.

This is much the same as the use of data for any patent application; however, data in the specific field of food products brings with it a potential problem that data relating to taste and mouthfeel are typically obtained via human taste panels. Arguably, data from taste panels is subjective and potentially of lower weight than objective data obtained in another technical field. Nevertheless, given that taste panels are the accepted testing method in the field of food, data from them typically are accepted by the EPO as evidence for an inventive step. For instance, the Board of Appeal in T 695/00 stated the following, in response to an argument from an opponent that the subjective nature of taste panels deprived the data of technical meaning:

[I]n the absence of any clear evidence to the contrary, the Board concludes that the evaluation of taste and smell by a panel of testers is the only generally accepted method for assessing the sensorial properties of marine oils and thus that the experimental data resulting therefrom are a reliable and appropriate basis for evaluating inventive step.

That being said, it is important to note that the devil is in the detail, and that an opponent may well be able to weaken the ability of a patent to rely on taste panel data, under certain circumstances. Further issues around the use of subjective taste characteristics in patent applications are discussed in our article regarding fermented foods – available here.

Given the subjective and time-consuming nature of obtaining data from taste panels, innovators are developing new testing methods in an attempt to provide an objective way of measuring the taste of food, as shown by a patent recently granted by the EPO. European Patent No. 2841565 titled “Human taste cells capable of continuous proliferation” was granted in 2018 to “B.R.A.I.N. Biotechnology Research and Information Network”. The proprietor describes how its technology is based on human tongue cells cultured in vitro, and “allows for a qualitatively reliable and considerably faster sampling of natural substances than with test subjects in a sensory panel”. It remains to be seen whether data from this interesting new testing method will begin to make its way into patent applications. Until that time arises, understanding how to use subjective data from taste panels in order to provide evidence of an inventive step before the EPO should be a key part of IP strategy in this fast-moving area.

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