Sea buckthorn (Hippophaë rhamnoides) berries are known to be very acidic, sour and astringent. Berries contain also various sugar alcohols and alkylated sugars and the contents vary during ripening. Our previous study demonstrated how ethyl-β-D-glucoside (EG) content may effect on pleasantness of sea buckthorn juice. In this study, we isolated the alkylated sugar from the juice of cultivar ‘Tytti’ and we studied its contribution to sourness, bitterness or astringencies (puckering or mouth-drying) in a water solution.

Sugar compounds of the juice were first isolated from acids using applied method of Tiitinen et al. (2005) with anion exchange column chromatography. In the second phase, EG was isolated from other sugars with column chromatography using a modified method of Nurminen et al. (2007). In both columns the sugars including EG was eluted with water and the whole process was carried out in food-grade conditions. The final purity of the fraction was assessed with gas chromatography and with spectrophotometer. The resulting EG-rich fraction was diluted to water (0.50g/100mL). The sensory panel (n=26) was trained to evaluate the four attributes using generic Labelled Magnitude Scale (gLMS). The two samples (water solution of EG and water) were evaluated in two sessions in randomized order and in controlled sensory laboratory conditions.

The final fraction contained 87 % of EG, 5 % glucose and 8 % quebrachitol. Additionally, it may have contained traces of water-soluble phenolic compounds. Due to low-yielding and time consuming isolation process the purity was compromised. In the end, only a 0.5 mL sample was applied on an assessors tongue in the two sessions. The fraction in water was significantly more bitter than water (n=26×2; t-test, p<0.05) and did not contribute to other attributes. Additionally, in open-ended descriptions the panelists described the fraction as “pungent” and “sharp”. This study further indicates that EG has a significant role in the sensory profile of sea buckthorn. Bitterness in foods can often be accepted as negative features. Therefore EG can be one of the factors contributing negatively to pleasantness. Better understanding of its sensory contribution and interactions with other berry components may aid to mask its possibly negative properties. Additional research with more purified EG in up-scale process is needed to verify the preliminary results of this study.