DOI: 10.5281/zenodo.17976248
title: D2O sweetness and its effect on different tastants
title: from paper https://www.nature.com/articles/s42003-021-01964-y

description: Raw data used to create Figure 2 in paper Sweet taste of heavy water, originally published as supplementary file.

 

Sensory evaluation experiments

A human sensory panel was used to resolve the gustatory effect in perception of D2O taste. Subjects between the ages 20 and 43 years were recruited. The study included 10 experiments with different groups of participants (15–30 subjects; between 4 and 12 males). The perception was tested by sensory tests as detailed below. Either sterile syringes with solutions (0.3 ml) or identical cups with solutions (7 ml), were presented in randomized order, unless otherwise noted. Participants were required to taste each solution using either ‘tip of the tongue’ or ‘sip and spit’ procedures, rinse their mouth with water after each solution and to wait for 30 s before moving to the next taste sample. All research procedures were ethically approved by the Committee for the Use of Human Subjects in Research in The Robert H. Smith Faculty of Agriculture Food and Environment, the Hebrew University of Jerusalem.

99.9% purity D2O was purchased from Sigma-Aldrich Corp, while 18 MΩ ultrapure grade was used for pure H2O. All water samples were placed under vacuum and treated by ultrasound to remove any dissolved gases. See below for more details on water purification.

D-glucose (CAS Number: 50-99-7), sucrose (CAS Number: 57-50-1), cyclamate (CAS Number: 139-05-9), quinine (CAS Number: 207671-44-1), and MSG (CAS Number: 142-47-2) were purchased from Sigma-Aldrich Corp. All compounds were dissolved in both types of water to a final concentration of 50, 75, and 100 mM for D-glucose and sucrose; 3.5, 4.5, and 5.5 mM for cyclamate; 0.1 and 0.32 mM for quinine; 10, 25, and 50 mM for MSG. Lactisole (CAS Number: 150436-68-3) was purchased from Domino Specialty Ingredients and dissolved to a final concentration of 0.9 mM in D2O water as well as in H2O. The concentration of lactisole was selected based on previous data43,53 and preliminary experiments in our lab, which showed that 0.9 mM decreases the sweetness of 100 mM sucrose. Sweeteners concentrations were selected to be in low intensity of sweetness. All solutions were prepared in the morning of the day of the experiment and were stored in individual plastic syringes (1 ml) for each participant.

The sweetness of heavy water and its effect on other taste compounds was evaluated in several independent experiments: (1) D2O sweetness relative to H2O (Fig. 2a); (2) D2O effect on sweetness of D-glucose (Fig. 2b), sucrose (Fig. 2c), and cyclamate (Fig. 2d); (3) D2O effect on quinine (Fig. 2e) and MSG (Fig. 2f); (4) Lactisole effect on D2O sweetness (Fig. 4b); Intensity of each taste modality—sweetness/bitterness/umami was evaluated on a 9-point scale on Compusense Cloud, ranging from 1 (no sensation) to 9 (extremely strong sensation). In addition, participants had to report any additional tastes they recognized. Statistical tests were conducted using JMP Pro 13 (JMP, Version 13. SAS Institute Inc., Cary, NC, 1989–2019).





Sweetness of D2O mixed at increasing ratios with H2O. Treatments not connected by the same letters are significantly different (p < 0.05 in Tukey Kramer test). b–f The effect of D2O (red) compared to H2O (blue) on glucose (b), sucrose (c), cyclamate (d), quinine (e), and MSG (f) taste-specific intensity. Asterisks indicate a significant (p < 0.05) difference between water types using the two-way analysis of variance (ANOVA) with a preplanned comparison t-test. All data are presented as the mean ± the Standard Error of Measurement (SEM); n =&thinsp;15–30 (4–12 males). The y axis shows the response for individual modalities, while the x axis is labeled with different water samples. Scale for each modality is labeled as 1 =&thinsp;no sensation, 3 =&thinsp;slight, 5 =&thinsp;moderate, 7 =&thinsp;very much, and 9 =&thinsp;extreme sensation.