Products 1 and 3 are commercially available, products 2 and 4 are experimental and not commercially available.

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1 Nutrition Scientist Valentina Breitenstein und Dr. Udo Kienle, Institut für Agrartechnik, Universität Hohenheim Workshop Stevia-Sensorics at conference of the German Society of Nutrition, Baden-Württemberg Branch, Alternative Sweeteners March, at Universität Hohenheim, Stuttgart, Germany A total of persons participated in the workshop. Four sweeteners based on Stevia rebaudiana have been tested under blind, but not randomized conditions. None of the participants have been aware about the nature and composition of the test preparations. All test samples have been dissolved in water (test liquid) at a dose which corresponds to a sweetness of a softdrink (equivalent to % sucrose solution). The test was done at room temperature. Each participant received a glass with ml of each test liquid. Each glass was numbered from to according to the content of the test liquid. An inquiry was filled by each participant with questions for the sensoric characterisation of each test sample. Test samples: Product : Commercial available steviolglycoside of a wellknown company with a composition of 9 percent Rebaudiosid A (E9). Product : The same test sample as product No. but with the attempt to improve the sensoric characteristics by employment of a physical process. This product is not commercially available (E9 experimental). Product : Commercial available steviolglycoside with a higher content of Stevioside, purity > 9 percent (E9). Product : A sweet low calorie food based on Stevia rebaudiana, version GoStevia EU-project. Products and are commercially available, products and are experimental and not commercially available. Test procedure: The participants have been advised to test and evaluate each test preparation one after the other and to start with test preparation No., then to switch to No., then to No. and then to No.. Between each test preparation the participant was advised to rinse their mouth with water. By this measure a carry-over of a taste sensation from one tests sample to the next should be avoided. Directly after each testing the evaluation inquiry should be filled in before starting with the next test sample. Evaluation of the test results: For the evaluation a quantitative descriptive analysis (QDA) with a scale/scoring system was used. The participants evaluated individually and subsequently in a questionnaire the sensory properties of the different test samples. Finally, a statistical analysis (SPSS) by Tukey s correction was used where the probability of no more than the significance level (p =,) exist to say that at least two means are significantly different when the underlying means are identical.

2 Evaluation of non-desired taste components: Consumers complain very often about the poor taste characteristics of steviol glycosides. Usually a bitter aftertaste and/or a licorice taste is reported together with taste sensations like herbal taste or an astringent taste sensations in the mouth. Test sample No bitter No licorice No herbal taste No astringent taste aftertaste aftertaste sensation Product 9% 9% % % Product % 9% % % Product % % % % Product 9% % 9% % The comparison of the results of product and shows that it is possible to improve the taste of conventional produced (by chemical process) steviol glycosides by physical process means. An improvement in the perception of bitterness, licorice aftertaste, herbal taste notes and also astringent sensation was noted by the participants. The result shows that it is possible to produce steviol glycosides without aftertaste. A biosynthetic production of steviol glycosides which is prepared by some companies may allow to overcome the sensorical problems of the steviolglycosides. It will be interesting to taste such steviol glycoisdes produced by biosynthesis in near future. A comparison of product and product do not reveal too much differences in the perception of bitterness or the licorice aftertaste. This shows that a well-produced Stevioside could compete in taste with a conventional Rebaudioside A and at much lower costs. The taste differences between a Rebaudiosdie A or a Stevioside are very often neglectable especially in prepared food or beverages. Product was shown to be superior in its taste perception recorded by the participants. Appraisal of the sweetness qualities of the test sample Consumers compare alternative sweeteners intuitionally with the sweetness qualities of sugar. Important is e.g. the development of sweetness or the long-lasting of sweet taste sensation. An optimal sweet taste should not be perceived to slow and should not last too long.,%,%,%,% Development of Sweetness Classification according to participant scores,% P P P P slow development - equilibrated - quick development -

3 Product and have a fast development of sweetness but the sweetness is also long-lasting. Product has a much slower perceiving of the sweet taste. However, the sweetness does not last such long than in products and. Product showed also a much slower development of the sweet taste but the lasting of the sweetness was neither too long nor too short. Classification according to participant scores,%,%,%,%,%,%,%,% P P P P short lasting - equilibrated - long lasting - The assessment of pleasant impact involves above classifications of the four test samples done by the participants. % % % % % % Pleasant Impact Classification according to participant scores % P P P P pleasant impact - neutral - non pleasant impact - The perception of the sweet taste (readiness and continuance) is an important component beside annoying components like bitter, liquorice or herbal taste. The test revealed that most participants associated test sample to with an unpleasant taste sensation. Test sample was classified by the participants rather as pleasant. Only %of the participants perceived tests sample as unpleasant. This shows that the task still remains to improve taste wise product until it can be released to the market in. We want to thank to all participants for their kind help in developing test sample.

4 Sensoric Assessment of the test samples Product : Commercial available steviolglycoside of a wellknown company with a composition of 9 percent Rebaudiosid A (E9). Test sample =pleasant, = not pleasant = short, = long = slow, = fast = flat, = full-bodied = no, = yes =no, = yes The evaluation was as follows: : too long : rapid sensation : some mouth feeling effect : was noted by participants : was noted by participants : was noted by participants : was noted by participants Herbal taste: none : none Astringent taste: slight : none : no pleasant sensation

5 Product : The same test sample as product No. but with the attempt to improve the sensoric characteristics by employment of a physical process. This product is not commercially available (E9 experimental). Test sample =pleasant, = not pleasant = short, = long = slow, = fast = flat, = full-bodied = no, = yes =no, = yes The evaluation was as follows: : too long : rapid sensation : notable mouth feeling effect : less than in tests sample : less than in tests sample : less than in tests sample : was noted by participants Herbal taste: none : none Astringent taste: none : none : no pleasant sensation

6 Product : Commercial available steviol glycoside with a higher content of Stevioside, purity > 9 percent (E9). Test sample =pleasant, = not pleasant = short, = long = slow, = fast = flat, = full-bodied = no, = yes =no, = yes The evaluation was as follows: : more equilibrated : not completely sufficient rapid sensation : slightly too less mouth feeling effect : clearly notable : was noted by participants : was noted by participants : was noted by participants Herbal taste: was noted by participants : slight Astringent taste: was noted by participants : slight : no pleasant sensation

7 Product : A sweet low calorie food based on Stevia rebaudiana, version GoStevia EU-project Test sample =pleasant, = not = short, = long = slow, = fast = flat, = full-bodied = no, = yes =no, = yes The evaluation was as follows: : more equilibrated : not completely sufficient rapid sensation : notable mouth feeling effect : none : none : none : pronounced Herbal taste: none : none Astringent taste: none : none : more pleasant taste impact

8 Comparison of the test samples Test sample distinguish from the other three test samples. It has the best pleasant impact, the sweetness does not last too long and avoids all strange taste sensations typically present in steviol glycosides. There is still a need to improve a little bit the taste sensation in respect of mouth feeling and the caramelic taste. Also a slight more quicker development of the sweetness would be preferable. test sample test sample Comparison test sample - test sample test sample =pleasant, = not pleasant = short, = long = slow, = fast = flat, = full-bodied = no, = yes =no, = yes The test arrangement was not randomized. This could not be done in another way during such a workshop at a conference. The non-randomized way of testing may have an influence on the test results especially for test sample. A carry-over of some taste sensations like bitter, liquorice etc. from test samples to to test sample could be possible. Anyhow test sample was preferred by the participants. In an open judgement at the end of the workshop only participants discarded test sample. However, more than participants discarded sample to. The results show that the consumer acceptance for test sample could be deemed as given.