T 0636/23 (Phloretin/FIRMENICH) of 5.9.2025

Summary of Facts and Submissions

I. The appeal was filed by the patent proprietor (appellant) against the opposition division's decision revoking the European patent.

II. Claim 1 of the patent as granted reads:

"A method of reducing the off-taste of a food or beverage containing a sweetener selected from the group consisting of common saccharide sweeteners, namely sucrose, fructose, glucose; sweetener compositions comprising natural sugars, namely corn syrup or other syrups or sweetener concentrates derived from natural fruit and vegetable sources; semisynthetic sugar alcohol sweeteners, namely erythritol, isomalt, lactitol, mannitol, sorbitol, xylitol, maltodextrin, glycerol, threitol, arabitol, ribitol, and dulcitol; artificial sweeteners, namely miraculin, aspartame, superaspartame, saccharin, saccharin-sodium salt, acesulfame-K, cyclamate, sodium cyclamate, and alitame; other sweeteners, namely trehalose, melizitose, melibiose, raffinose, palatinose, lactulose, cyclamic acid, mogroside, tagatose, maltose, galactose, L-rhamnose, D-sorbose, maunose, lactose, L-arabinose, D-ribose, D-glyceraldehyde, curculin, brazzein, mogroside, Neohesperidin dihydrochalcone, neotame and other aspartame derivatives, D-tryptophan, D-leucine, D-threonine, glycine, D-asparagine, D-phenylalanine, L-proline, maltitol, hydrogenated glucose syrup, magap, sucralose, lugduname, sucrononate, sucrooctate, monatin, phyllodulcin, hydrogenated starch hydrolyzate, stevioside, rebaudioside A, rebaudioside D, rebadioside M, and other sweet Stevia based glycosides, lo han guo, thaumatin, monellin, carrelame and other guanidine-based sweeteners, wherein the off-taste is selected from the group consisting of licorice, astringency, bitterness and sweet lingering comprising adding 10 to 35 ppm, by weight, of the total weight of the food or beverage, phloretin to the food or beverage wherein the phloretin is provided in the absence of a bitterness-masking aroma substance selected from the groups consisting of homoeriodictylol, homoeriodictyol sodium salt, homoeriodictylol potassium salt or mixtures thereof and wherein the phloretin does not enhance the sweetness of the food or beverage."

III. The documents submitted during the opposition proceedings included:

D1:|US 2013/0316060 A1|

D3:|EP 2 253 226 B1 |

D4:|WO 2007/107596 A1 |

IV. The opposition division found, inter alia, that the claimed invention was not sufficiently disclosed to be carried out by the skilled person. The patent did not provide sufficient guidance for using phloretin to decrease the off-taste of compositions containing sweeteners without inducing an increase in their sweetness. D1, D3 and D4 showed that phloretin increased the sweetness of compositions containing sweeteners. The patent did not provide evidence that, contrary to the teaching of these documents, phloretin did not induce this effect. The skilled person had to resort to trial and error to carry out the invention. This resulted in an undue burden.

V. In its statement setting out the grounds of appeal, the appellant defended its case relying on the set of claims of the patent as granted (main request) and on auxiliary requests 1 to 11, filed with that statement. With its letter dated 2 December 2024, it filed auxiliary requests 12 to 23.

VI. With his reply to the appellant's statement setting out the grounds of appeal, the opponent (respondent) filed document D10.

D10:|Lothar Sachs, Angewandte Statistik, Springer Verlag, Berlin, 2000, pages 184 and 185|

VII. During the oral proceedings held before the board, the appellant relied on the main request and on auxiliary request 1, which correspond to the previously filed auxiliary requests 7 and 19 respectively. All other previously filed claim requests were withdrawn.

VIII. Claim 1 of the main request reads as follows.

"A method of reducing the off-taste of a food or beverage containing a sweetener, wherein the sweetener is stevia, wherein the off-taste is selected from the group consisting of licorice, astringency, bitterness and sweet lingering comprising adding 10 to 35 ppm, by weight, of the total weight of the food or beverage, phloretin to the food or beverage wherein the phloretin is provided in the absence of a bitterness-masking aroma substance selected from the groups consisting of homoeriodictylol, homoeriodictyol sodium salt, homoeriodictylol potassium salt or mixtures thereof and wherein the phloretin does not enhance the sweetness of the food or beverage."

IX. Claim 1 of auxiliary request 1 reads as follows.

"Use of phloretin to reduce the off-taste of a food or beverage containing a sweetener, wherein the sweetener is stevia, wherein the off-taste is selected from the group consisting of licorice, astringency, bitterness and sweet lingering comprising adding about 10 to about 35 ppm, by weight, of the total weight of the food or beverage, phloretin to the food or beverage wherein the phloretin is provided in the absence of a bitterness-masking aroma substance selected from the groups consisting of homoeriodictylol, homoeriodictyol sodium salt, homoeriodictylol potassium salt or mixtures thereof and wherein the phloretin does not enhance the sweetness of the food or beverage."

X. The appellant essentially argued that the opposed patent provided the skilled person with sufficient information to carry out the claimed invention. The experiments described in the patent provided evidence that the addition of phloretin to foods and beverages containing stevia decreased off-tastes without increasing their sweetness. Neither D1, D3 and D4, nor example 2 of the patent provided evidence that phloretin increased the sweetness of these foods and beverages. Thus, contrary to the opposition division's finding, the claimed invention was sufficiently disclosed.

XI. The respondent essentially argued that the teaching of D1, D3 and D4 and example 2 of the opposed patent raised reasonable doubts that phloretin could be added to a food or beverage comprising stevia without increasing its sweetness. Thus, the skilled person could not carry out the invention, or at least could not carry it out without an undue burden across the entire scope claimed. Hence, as already decided by the opposition division, the claimed invention was insufficiently disclosed.

Requests

XII. The patent proprietor (appellant) requested that the decision under appeal be set aside, that sufficiency of disclosure be acknowledged and that the case be remitted to the opposition division for further prosecution on the basis of:

- the main request (filed as auxiliary request 7 with the statement setting out grounds of appeal) or

- auxiliary request 1 (filed by letter dated 2 December 2024 as auxiliary request 19)

XIII. The respondent (opponent) requested that the appeal be dismissed.

Reasons for the Decision

1. Admission of document D10

1.1 The appellant requested that document D10, filed by the respondent with his reply to the statement of grounds of appeal, not be admitted. However, as argued by the respondent and conceded by the appellant during the oral proceedings, D10 merely represents basic statistical concepts which are part of common general knowledge.

1.2 Therefore, these concepts can be taken into account when interpreting the relevance of the results in the patent without dealing with the question of admission of D10. This question therefore need not be decided.

2. Main request: sufficiency of disclosure

2.1 The claimed invention relates to a method for reducing the off-taste of a food or beverage containing a sweetener, wherein the sweetener is stevia. The method provides the addition of 10 to 35 ppm of phloretin to the food or beverage. Furthermore, it requires that the phloretin does not enhance the sweetness of that food or beverage.

2.2 This means, in other words, that phloretin must reduce the off-taste of that food or beverage, without causing an increase in its sweetness.

2.3 The opposition division has found that the patent failed to provide sufficient guidance regarding adding phloretin to foods or beverages comprising stevia without enhancing their sweetness. For this reason, it concluded that the claimed invention was insufficiently disclosed.

2.4 The appellant contested the opposition division's finding, essentially arguing as follows.

- The opposed patent described working examples showing how to put the claimed invention into practice. The results of the tests in examples 1, 2 and 4 showed that the addition of phloretin to foods and beverages containing stevia decreased off-tastes without increasing their sweetness. The number of panellists used for the tests was sufficiently large to provide significant results. The wording "did not enhance sweetness" in claim 1 meant that the sweetness was not enhanced in a statistically significant manner.

- There was no evidence that the invention could not be carried out by a skilled person. D1, D3 and D4 did not provide evidence that phloretin increased the sweetness of compositions comprising stevia.

- The slight increase in sweetness observed in example 2 of the opposed patent could be overcome by lowering the amount of stevia or by not using pomegranate. The claimed scope being narrow, performing tests involving some trial and error to carry out the invention did not amount to an undue burden.

- In view of the results shown in the patent, there was a strong presumption that the claimed invention was sufficiently disclosed. The burden to demonstrate that it could not be put into practice was on the opponent and had not been discharged.

2.5 The board is not convinced by the appellant's arguments.

2.5.1 As noted by the respondent during the oral proceedings, paragraph [0002] of the opposed patent, which sets out the background of the invention, states that phloretin was used as a modulator of sweetness before the filing date. The first document cited in this paragraph, US 2013/316060, which is D1 in the present case, confirms that phloretin increases the sweetness of foods comprising sweeteners, including stevia, and can be used to adjust their after-taste, see paragraphs [0009], [0027], [0036] and [0037] and example 1. Further documents confirming that the use of phloretin to increase the sweetness of compositions containing sweeteners was known before the filing date are D3 (paragraph [0001]) and D4 (first paragraph of page 1).

2.5.2 Against this background the patent proposes using phloretin to decrease the off-taste of compositions containing sweeteners of very different types, including stevia, without increasing their sweetness. As pointed out by the respondent, the patent does not indicate how this effect, which clashes with the teaching of D1, D3 and D4, can be achieved. The results in the patent, and in particular those in example 2, cast further doubts on the fact that phloretin can be added to a composition containing stevia without increasing its sweetness.

2.6 The appellant expressed the opinion that D1, D3 and D4 did not provide convincing evidence that phloretin increased the sweetness of foods and beverages comprising sweeteners, stevia in particular. It argued that these documents did not indicate whether the results of the described tests had a level of confidence of at least 90%, a condition that the results had to fulfil to be considered statistically relevant. Furthermore, stevia was not used for the tests described in the prior-art documents. Conversely, the experiments described in the opposed patent, and in particular examples 1 and 4, made it credible that phloretin did not increase the sweetness of stevia.

2.7 These arguments are not convincing.

2.8 According to established case law, the principle of the free evaluation of evidence applies universally in proceedings before the EPO when assessing any means of evidence. The EPO deciding body decides on this issue in the light of its conviction, taking into account the evidence available in the proceedings and on the footing that one set of facts is more likely to be true than the other. For this reason, in proceedings before the EPO, when deciding on whether a certain technical effect is taking place, it is not an absolute prerequisite to present a statistical analysis of the results. Whether such analysis is necessary depends on the circumstances of the case (see also T 2036/21, Reasons 3.25 to 3.29).

2.9 In the present case, the board considers that the available evidence casts serious doubts on the fact that phloretin can be added to a food or beverage comprising a sweetener without enhancing its sweetness. In fact, the evidence set out in D1, D3 and D4 actually makes it credible that the addition of phloretin increases the sweetness of foods and beverages comprising sweeteners, including stevia.

Document D4

2.9.1 D4 describes the use of 4-hydroxydihydrochalcone compounds in an amount of 10 to 30 ppm, which is essentially the amount specified in claim 1, to increase the sweetness of compositions comprising sweet-tasting substances (page 17, lines 7 to 15 and lines 28 to 29, page 1, lines 1 to 9 and claim 1). A preferred 4-hydroxydihydrochalcone compound is phloretin (page 4, lines 7 to 10, page 8, compound 4, page 11, lines 15 to 20). The sweet-tasting substances whose sweetness is to be increased include stevia, see page 16, line 22 and page 17 line 2.

2.9.2 The results of the tests shown in the examples set out in D4, conducted by a "group of expert people" (page 43, line 8), make it credible that phloretin increases the sweetness of compositions comprising sweet-tasting substances.

2.9.3 Example 9 on pages 56 and 57 of D4 shows that the addition of phloretin to a composition comprising sucrose, a sweetening agent, increases its sweetness. Reference is made, in particular, to preparations A, B and C. Preparation C differs from composition B only in that it additionally comprises 30 ppm of phloretin. The sweetness of composition C is enhanced by 37% compared to composition B and "an even more substantially intense sweetness was perceptible" (see the tables on page 56 and page 57, lines 3 and 4). Furthermore, the sweetness of composition C is comparable to that of composition A, which comprises a higher amount of sucrose and a lower acidic component.

2.9.4 Example 12 on pages 59 and 60 of D4 shows similar results. Preparation C differs from preparation B only in that 30 ppm phloretin are present. It is stated that "[p]reparation C was substantially sweeter than comparison preparation B". Furthermore, it is stated that composition C had the same sweetness as composition A, which comprised a higher amount of sucrose, see page 60, lines 5 to 9.

2.9.5 The tests shown in example 1 on page 43 of D4 confirm the results observed in examples 9 and 12 using sucrose or glycerin as sweeteners.

2.9.6 The appellant argued that D4 did not show whether the results disclosed in D4 were statistically significant. It further argued that none of the tested compositions contained stevia as sweetener. Therefore, the teaching of this document was not relevant and should be disregarded.

2.9.7 These arguments are not convincing. D4 focuses specifically on the problem of enhancing the sweetness of compositions comprising sweetening agents. It describes the preparation of relevant compositions, indicating the amounts of the relevant compounds. D4 further states that the sweetness of the compositions was tested by a "group of experts" or "test people". These experts/people were asked to indicate a value for "impression of sweetness" on a scale from 1 to 10 which was used for classification (see page 43, lines 3 to 9, and page 60, lines 5 to 9). Moreover, D4 states that compositions comprising phloretin were substantially sweeter than comparison compositions not comprising it (page 60, lines 7 to 9). In addition, in the case of example 1 the results indicate that phloretin increases sweetness, and that the p value is <0.001 in one case and <0.05 in the other.

2.9.8 It is to be assumed that the tests described in D4 were carried out with all due care and in a manner suitable to provide significant results as to the sweetness of the tested compositions.

2.9.9 Furthermore, D4 provides the general teaching that the claimed 4-hydroxydihydrochalcone compounds, including phloretin, increase the sweetness of sweet-tasting substances of different types, including stevia. Although the tests described in the aforementioned examples were carried out using sucrose or glycerine as sweeteners, there is no technical reason to doubt that the same effects will occur also with compositions containing other sweeteners, including stevia. It is also noted that the level of generalisation used in the application for the opposed patent when defining the invention is similar to or even exceeds that applied in D4: the application describes tests using only stevia and sucrose as sweeteners, although its teaching is that the invention can be carried out with an extremely long and heterogeneous list of sweeteners.

2.9.10 For the aforementioned reasons it is concluded that D4 renders it credible that amounts of phloretin as defined in claim 1 increase the sweetness of compositions comprising sweeteners, including stevia.

Document D1

2.9.11 D1 confirms the teaching of D4. This document relates to the use of phloretin and/or trilobatin to reduce the aftertaste of beverages containing sweetening agents (paragraph [0009] and claim 1). A preferred natural sweetening agent is stevia (see paragraphs [0036] and [0037]).

2.9.12 Example 6 of D1 demonstrates that the addition of 3 ppm of phloretin (sample C) to a composition comprising a natural sweetener increases the sweetness above that of a control composition not comprising phloretin (sample A). The amount of phloretin according to claim 1 is higher, namely 10 to 35 ppm. However, since 3 ppm phloretin is sufficient to enhance the sweetness of composition C, the skilled person would expect that a higher amount of phloretin would increase even further the sweetness of the composition. The appellant argued that there was no evidence for this assumption. However, since it is logical to expect that the effect of phloretin correlates with its concentration, it was the appellant's responsibility to provide evidence that higher phloretin concentration would (surprisingly) not further increase the sweetness of compositions comprising a sweetener.

2.9.13 The appellant noted that example 6 of D1 described samples (B and D) containing trilobatin in addition to 7.5 and 10.5 ppm phloretin. Furthermore, it noted that, according to paragraph [0009] of the patent, trilobatin and phloretin influenced each other's taste impression. Thus, it was not possible to draw conclusions as to the effect of phloretin from these tests. This appears to be correct, insofar as compositions comprising phloretin are compared only with others comprising both phloretin and trilobatin. For example, no proper comparisons can be made between sample C, which contains phloretin only, and sample B, which contains both phloretin and trilobatin. However, when a comparison is made between sample B and sample D, which contains the same amount of trilobatin as sample B but an increased amount of phloretin, this argument is not applicable and the results confirm that a higher amount of phloretin increases the sweetness of compositions containing sweeteners. In this context, it is noted that claim 1 does not exclude compositions including trilobatin along with phloretin.

2.9.14 The appellant also argued that example 6 of D1 did not describe a statistical analysis of the results. However, D1 indicates that the tests were carried out by test persons assessing different characteristics, including sweetness, ranking them on a 9-point scale, see paragraph [0088]. Thus, as already discussed when dealing with D4, despite the fact that a statistical analysis of the data is not explicitly mentioned in D1, there are no reasons not to consider the results credible.

2.9.15 For these reasons, the results in D1, and in particular the comparison of the results observed using samples A and C, confirm the finding of D4 that phloretin increases the sweetness of compositions comprising a sweetening agent. Furthermore, as in the case of D4, there is no reason to doubt that the effects observed in the tests in D1 will occur if other sweeteners are used, including stevia, which is a preferred sweetener of D1.

Document D3

2.9.16 D3 focuses, like D4, on the use of compounds which increase the sweetness of compositions comprising sweetening agents. Example 5, on page 29 of D3, describes tests determining the sweetness of compositions comprising phloretin, a methoxy-flavan compound and a sugar, presumably sucrose, as sweetening agent. Samples E and F of example 5 differ only in that sample F contains 20 ppm of phloretin. The observed sweetness values, calculated relative to sample A, which comprises a higher amount of sugar, make it credible that the addition of phloretin to sample F increases sweetness compared to sample E. Note that the variation in sweetness of from -16% for sample E to -8% for sample F (calculated relative to sample A) indicates that sample F has a stronger sweetness.

2.9.17 The appellant argued that the tests in example 5 were not relevant, because samples E and F comprised a methoxy-flavan compound, in addition to phloretin. This was the compound that increased sweetness, rather than phloretin. D3 did not disclose samples comprising phloretin only. Furthermore, D3 referred to "sugar", without indicating which kind of sugar was used. This was not necessarily sucrose. The statistical significance of the results was not indicated either.

2.9.18 These arguments are not convincing. Although D3 teaches that methoxy-flavan compounds enhance the sweetness of compositions comprising sweetening agents, the comparison between samples F and E, which contain the same amounts of a methoxy-flavan compound, indicates that the addition of phloretin enhances the sweetness of the tested composition. As noted by the respondent, samples E and F differ only in the presence of phloretin and claim 1 of the main request does not exclude the inclusion of further compounds, in addition to phloretin. Moreover, example 5 of the opposed patent refers, in exactly the same way as example 5 of D3, simply to "sugar", without clarifying whether that "sugar" was sucrose. In the field, the generic term "sugar" is typically used to identify sucrose. Furthermore, even if the p value for the results relating to sample F is high (0.44), the data suggest that phloretin increases sweetness. As in the case of D1 and D4, there is also no reason to doubt that the effects observed in the tests in D3 would occur using other sweeteners, including stevia, which is a preferred sweetener of D3.

2.9.19 For these reasons, the overall picture given by the results presented in D1, D3 and D4 makes it credible that the addition of phloretin enhances the sweetness of compositions comprising sweetening agents, including stevia.

2.10 Concerning the tests described in the opposed patent, the board agrees with the respondent that the observed results do not make it credible that the addition of phloretin does not enhance the sweetness of compositions containing sweetening agents, including stevia.

2.10.1 The appellant argued that the results of the tests described in the patent did not show a statistically significant increase in sweetness, because the p values obtained when measuring sweetness were above 0.05. However, as observed by the respondent relying on basic statistical concepts as described in D10, if the results concerning sweetness are not considered statistically significant on the ground that the p value is above 0.05, those results cannot confirm the hypothesis that phloretin does not enhance sweetness either.

2.10.2 This means that, if the results presented in the opposed patent are considered to lack significance, they are also unsuited to demonstrating that, contrary to the teaching of D1, D3 and D4, phloretin does not increase the sweetness of compositions comprising sweetening agents, including stevia.

2.10.3 Conversely, insofar as the effects on sweetness reported in the opposed patent are taken into account, the results of the tests in example 2 suggest that, despite the p value of 0.1244, phloretin enhances the sweetness of the tested composition containing stevia. In this context, reference is also made to figure 2 of the opposed patent. In this figure, which reflects how the outcome of the tests was interpreted by the inventors, the data are plotted in a manner which indicates that phloretin increased the sweetness of the tested composition containing stevia.

2.10.4 No increase in sweetness was reported when phloretin was added to Stevia in example 1. However, the p value in this case is 0.5, which is typically considered an indication that the observed effect is merely due to random variation.

2.10.5 Insofar as example 5 is taken into consideration, paragraphs [0047] to [0050] appear to indicate that no significant change in sweetness was observed. However, figure 5 was plotted in a manner which shows that, as in example 2, an increase in sweetness was actually observed.

2.10.6 To summarise, there are two possible ways of dealing with the results relating to sweetness presented in the patent. The first is to disregard all these results, on the ground that they are not statistically significant (p being above 0.05). In this case the results would not be suitable for confuting the teaching of D1, D3 and D4 that phloretin enhances the sweetness of compositions comprising sweetening agents, including stevia. The second possibility is to take the results into account, considering what they suggest, despite the fact that the p value exceeds 0.05. In this case, the example carrying the greatest weight would be example 2, which has the lowest p value and suggests that phloretin increases the sweetness of the tested beverage comprising stevia.

2.10.7 Irrespective of which of the two aforementioned options is chosen, the overall picture provided by the available results casts reasonable doubt on the fact that phloretin can be added to a food or beverage comprising stevia to reduce off-taste, while not enhancing its sweetness. The fact that D1, D3 and D4 do not represent "common general knowledge", as argued by the appellant, is irrelevant. What is relevant is that these documents make it credible that phloretin increases the sweetness of foods and beverages comprising sweeteners, including stevia.

2.10.8 This means that the patent does not provide sufficient evidence to enable the skilled person to carry out the invention while simultaneously preventing the increase in sweetness caused by phloretin.

2.10.9 The appellant argued that the skilled person would be able to avoid the increase in sweetness measured when using 35 ppm of stevia, as in example 2 of the opposed patent, by lowering the amount of stevia or by not using pomegranate. It noted that paragraph [0009] and example 1 of the patent suggested using amounts of phloretin of 20 ppm.

2.10.10 These arguments are not convincing, because 35 ppm of stevia is clearly described as being an amount suitable for carrying out the invention in the opposed patent and in claim 1 of the main request. Furthermore, there is no teaching in the patent that the amount of phloretin is to be lowered, e.g. to 20 ppm, in order to prevent undesired increases in sweetness. There is no indication that pomegranate may induce an increase in sweetness either. Consequently, the skilled person would have to rely on trial and error in order to find possible ways of carrying out the claimed invention.

2.11 For these reasons, the board concurs with the opposition division's finding that the method defined in claim 1 is not sufficiently disclosed (Article 83 EPC).

3. Auxiliary request 1: sufficiency of disclosure

3.1 Claim 1 of auxiliary request 1 differs from claim 1 of the main request in that it defines the use of phloretin to reduce the off-taste of food and beverages containing stevia without enhancing their sweetness, rather than a method in which phloretin is used for this purpose.

3.2 The appellant has not set out reasons why the conclusions reached for the main request would not be applicable to the auxiliary request. The board cannot see any such reasons either.

3.3 Consequently, the board concludes that the invention defined in claim 1 of auxiliary request 1 is not sufficiently disclosed either (Article 83 EPC).

Order

For these reasons it is decided that:

The appeal is dismissed.