Abstract
Sourness threshold values (S.T.V.) of four inorganic acids and twenty five organic acids were determined and the correlation between their structure and S.T.V. was discussed.
1) S.T.V. of inorganic acids were related with their dissociation constants.
2) S.T.V. of the saturated straight chain monobasic acids decreased as their carbon number increased. S.T.V. of the branched chain monobasic acids were higher than those of the straight chain monobasic acids.
3) S.T.V. of the aliphatic dibasic acids increased with increase in the carbon number and these were related with their dissociation constants.
4) The organic acids to which another polar group such as -OH or -Cl was attached had a slight tendency to have higher dissociation constants and lower S.T.V. than the aliphatic acids.
5) S.T.V. of the polybasic acids were related with the first dissociated hydrogen ion.
These results suggest that the dissociation constants and the balance between hydrophobic and hydrophilic group affect S.T.V. of organic acids.
