The present invention relates to flavor oils including mint-, fruit- and spice-type flavors that are specially processed to substantially eliminate low-molecular weight sulfur compounds, in particular dimethyl sulfoxide (DMSO), which has been found to be the main precursor of malodorous species such as dimethyl sulfide and methyl mercaptan. These malodorous species are produced via oxidation-reduction reactions involving such sulfur-containing compounds present in flavor oils. A preferred processing method is an aqueous-washing process, which has advantages of being simple, inexpensive and easy to implement while importantly avoiding the problems of typical processes including non-selective removal of desirable components and subjecting the flavor oils to extreme conditions that may destroy other components and result in undesirable changes in flavor or odor character. Other processing methods to selectively remove non-desired components include (1) distillation to remove polar low boiling point components, (2) filtration through adsorbents selective for sulfur compounds, (3) countercurrent extraction and (4) column chromatography. The processing methods may optionally be followed by reengineering to add back desired components that may have been removed or altered during the processing. The specially processed flavor oils are particularly useful in oral care compositions comprising components with chemical reducing capability such as stannous ions, which react with the sulfur-containing compounds to produce malodorous products.
