Moreover, NHBD for the bitterants is predominantly ranging from 0 to 2 (Figure S3), and NHBA for the non-bitterants mainly varies from 1 to 3 (Figure S4). Similarly, the distributions of NHBA for the bitterants and non-bitterants have peaks at 2 and 4 respectively. Thus, the comparisons of NHBD or NHBA imply that the bitterants are slightly less hydrophilic than the non-bitterants. In addition, the scatter plots of NHBA vs. NHBD show that the distributions for the bitterants and non-bitterants cannot be easily distinguished from this view (Figure 1B). Therefore, it seems that logP, MW, NHBD, and NHBA are not good to intuitively discriminate the bitterants and non-bitterants.