Sensitive to music? Examining the crossmodal effect of audition on sweet taste sensitivity.

Previous research has shown that music can influence taste perception. While most studies to date have focused on taste intensity ratings, less is known about the influence of musical stimuli on other parameters of taste function. In this within-subjects experiment (N = 73), we tested the effects of three sound conditions (High Sweetness soundtrack - HS; Low Sweetness soundtrack - LS; and Silence - S) on sweet taste sensitivity, namely, detection and recognition. Each participant tasted nine samples of sucrose solutions (from 0 g/L to 20 g/L) under each of the three sound conditions in counterbalanced order. We assessed the lower concentrations at which participants were able to detect (detection threshold) and correctly identify (recognition threshold) a taste sensation. Additionally, the intensity and hedonic ratings of samples above the recognition threshold (7.20 g/L) were analyzed. Affective variations (valence and arousal) in response to the sound conditions were also assessed. Although music did not lead to significant differences in mean detection and recognition thresholds, a larger proportion of sweet taste recognitions was observed at a near-threshold level (2.59 g/L) in the HS condition. The intensity and hedonic ratings of supra-threshold conditions were unaffected by the music condition. Significant differences in self-reported mood in response to the sound conditions were also observed. The present study suggests that the influence of music on the sweet taste perception of basic solutions may depend on the parameter under consideration.

The Influence of (Poly)phenol Intake in Saliva Proteome: Short- and Medium-Term Effects of Apple.

The relationship between salivary proteome and dietary habits was studied in previous works, where a relationship between salivary proteins like cystatins and polyphenol/tannin levels in diet was observed. However, it remains to be elucidated if this association results from an effect of polyphenol-rich food ingestion on saliva composition. The aim of this work was to test the effects of apple intake on the saliva proteome, both in the short and medium term (after 4 days of continuous intake). By incubating saliva samples with apple phenolic-rich extract, protein bands containing α-amylase, S-type cystatins, and proline-rich proteins (PRPs) appeared in the fraction that precipitated, showing the potential of these (poly)phenols to precipitate salivary proteins. Among these, it was salivary cystatins that presented changes in their levels both in the saliva samples collected immediately after apple intake and in the ones collected after 4 days of intake of an extra amount of apple. These results support the thought that intake is reflected in the salivary proteome. The effect of a polyphenol-rich food, like the apple, on salivary cystatin levels is in line with results observed in animal models and, due to the involvement of these proteins in oral food perception, it would be interesting to explore in future studies the effect of these changes on sensory perception and acceptance of polyphenol-rich food.

How Different Snacks Produce a Distinct Effect in Salivary Protein Composition.

Saliva secretion changes in response to different stimulation. Studies performed in animals and humans suggest that dietary constituents may influence saliva composition, although the dynamics of these changes, and how they are specific for each type of food, are little known. The objective of the present study was to access the short-term effects of different foods in salivation and salivary protein composition. Twelve participants were tested for four snacks (yoghurt, bread, apple and walnuts). Non-stimulated saliva was collected before and at 0', 5' and 30' after each snack intake. Flow rate, total protein, alpha-amylase enzymatic activity and salivary protein profile were analyzed. Yoghurt and apple were the snacks resulting in higher salivary changes, with higher increases in flow rate and alpha-amylase activity immediately after intake. The expression levels of immunoglobulin chains decreased after the intake of all snacks, whereas cystatins and one pink band (proline-rich proteins-PRPs) increased only after yoghurt intake. Walnut's snack was the one resulting in lower changes, probably due to lower amounts eaten. Even so, it resulted in the increase in one PRPs band. In conclusion, changes in saliva composition varies with foods, with variable changes in proteins related to oral food processing and perception.