Unveiling brain response mechanisms of citrus flavor perception: An EEG-based study on sensory and cognitive...

Citrus flavors are globally popular in food industry, yet research on the perceptual preferences of various citrus flavors is limited. Based on the subjective sensory evaluation, this study introduces a novel sensory analysis approach, using electroencephalography (EEG), to objectively measure the sensory and cognitive responses to nine citrus flavors, including d-limonene, concentrated (H-) and original essential oils of sweet orange (SEO), bergamot EO (BEO), lemon EO (LEO), and grapefruit EO (GEO). Results revealed that δ (0.5-4 Hz) and α (8-13 Hz) waves activity predominated in brain responses to citrus flavor, with greater activity observed in frontal and central regions compared to other areas. Sniffing citrus EOs triggered more complex and dynamic electrical activity than d-limonene, indicated by higher power density across all frequency bands (0.1-30 Hz). Interestingly, while the original citrus EOs were associated with higher self-reported acceptability, the concentrated forms elicited greater brain responses. Specifically, H-SEO and L-LEO eliciting significantly greater δ and α wave activity in the prefrontal region than their original forms (P < 0.05). A preliminary correlation was observed between brain laterality in α waves power and acceptability scores of citrus flavor, with δ waves power in the prefrontal region further demonstrating an effective reflection of self-reported acceptability scores for SEO and LEO stimuli. This is the first EEG-based study to compare brain responses to different citrus flavors, providing important implications for the food industry in optimizing product formulations and enhancing consumer experiences.