Recent advances in investigating odor-taste interactions: Psychophysics, neuroscience, and microfluidic techniques

There is a limited understanding of odor-taste interactions at the molecular levels about how these interactions influence flavor perception. Microfluidic technology used small volumes of fluids in the microscale channels and chambers. It has the potential to provide high throughput assays as well as manipulate organ-on-chips models to simulate the complex interaction of organs in the body. This review discusses the progress and limitation of psychophysics, electroencephalography, and functional magnetic resonance imaging to investigate odor-induced taste perception. The application of organ-on-chip models of the nasal mucosa, oral cavity, and brain-gut axis with microfluidics is also discussed. Sensory results showed congruency between taste and odor affected the extent to which odor enhances taste perception. EEG and fMRI demonstrated the cross-modal interactions occur within primary sensory cortices in the brain, but the previous learning and experience are equally important. The multi-channel on the microfluidics not only provides an advantage to separate macromolecules in the sample matrix but can also offer higher throughput than conventional item-by-item detection and decreases reagents and sample consumption. It is feasible to establish in vitro sensory models to investigate interactions among flavor components with olfactory/taste receptors, brain, gut, etc.