Exploring synesthetic perception in traditionally produced boza enriched with varying ratios of hibiscus

Sensory and perceptual studies on food consumption require a multidisciplinary approach that focuses not only on taste preference but also on understanding individuals' cognitive and cross-sensory responses to sensory stimuli. In line with this, the study examined the sensory characteristics of boza, a traditional fermented beverage, formulated with varying concentrations of hibiscus (Hibiscus sabdariffa L.) concentrate, and the synesthetic associations it evoked in the perception of panelists. The research was conducted using a two-stage experimental design. In the first stage, sensory evaluations were performed on a total of four different boza samples by a semi-trained panel group of 33 students from the gastronomy department. These samples included a control sample of plain boza without hibiscus concentrate and three samples containing hibiscus concentrate at concentrations of 7%, 14%, and 21%. In the second stage, a synesthesia pre-assessment test was applied, followed by a total of five different cross-sensory pairing experiments. Within the scope of these experiments, applications were carried out based on taste-based color-taste experiments, smell-based experiments, smell-visual element experiments, and auditory-based taste-music stimuli on the boza samples. Statistical analyses revealed that as the hibiscus ratio increased, the acidic structure of the boza became more pronounced, the color tone shifted toward red, and the viscosity decreased. The panelist gave the highest score to the boza sample containing 21% hibiscus concentration, which was found to be balanced in terms of taste and appearance; the lowest score was given to the boza sample containing 14% hibiscus concentration, which had a paler color profile. Synesthetic findings showed that boza samples with higher hibiscus content created more intense and consistent associations; these samples were more consistently paired with sour tastes, dark color groups, sharp angular shapes, and fast-paced music. The research results confirmed that the contribution of hibiscus concentration is effective not only on physical characteristics but also on mental and perceptual representations. Furthermore, the synesthesia-based approach followed in the study demonstrated the applicability of intermodal interactions in the context of neurogastronomy for examining multisensory effects on food products. In this context, it is recommended that product development and sensory evaluation studies be conducted using a sensory integrity approach based on panelists' multisensory pairings, without being limited to physical criteria.