Background: Oral food perception plays a major role in food acceptance, although the way it relates with food preferences and final choices in adults is still debatable. The objective of the present study was to assess the relationship between gustatory function, dietary habits and fruit and vegetable preferences. Methods: Recognition thresholds, suprathreshold and hedonics were accessed for sweet, bitter, sour, salty and astringency in 291 adult participants. A Food Frequency Questionnaire (FFQ) and a questionnaire for assessment of preferences for individual fruit and vegetables were filled by the participants. Results: Three clusters were obtained: “most sensitive”, “less sensitive” and “less sensitive only for sour”. The less sensitive cluster showed lower preferences for fruit and vegetables and higher intake of sweets and fast foods, whereas higher preferences for sweet veggies were observed in the “most sensitive” cluster. Basic tastes and astringency hedonics did not associate with fruit and vegetable preferences, but the sensitivity for these oral sensations did. Conclusions: Taste and astringency sensitivities are related with the preference for fruit and vegetables, being also associated with some dietary habits. The effectiveness of the strategies to promote plant-based healthy food consumption may benefit from the knowledge of individuals’ gustatory function.

It is widely recognized that smelling food results in a mouth-watering feeling and influences appetite. However, besides changes in volume, little is known about the effects that food odours have on the composition of saliva. The aim of the present study was to access the effects that smelling bread has on saliva proteome and to compare such effects with those of chewing and ingesting it. Besides a significant increase in saliva flow rate, together with a decrease in total protein concentration, bread odour induced changes in the proportion of different salivary proteins. The expression levels of two spots of cystatins and two spots of amylase increased due to olfactory stimulation, similar to what happened with bread mastication, suggesting that odour can allow anticipation of the type of food eaten and consequently the physiological oral changes necessary to that ingestion. An interesting finding was that bread odour increased the expression levels of several protein spots of immunoglobulin chains, which were decreased by both bread or rice mastication. This may be of clinical relevance since food olfactory stimulation of salivary immunoglobulins can be used to potentiate the oral immune function of saliva. Moreover, the effects of bread odour in the levels of salivary proteins, previously observed to be involved in oral food processing led to the hypothesis of an influence of this odour in the sensory perception of foods further ingested. Further studies are needed to elucidate this point, as well as whether the changes observed for bread odour are specific, or if different food odours lead to similar salivary proteome responses.

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.

Dietary polyphenol exposure is known to change protein saliva composition in rodents, but less is known in humans. The present study aimed to assess the relationship between saliva protein composition and adherence to Mediterranean Diet (MD) and polyphenol intake levels. Participants were assessed for their dietary habits, which were converted in Mediterranean adherence level, according to Mediterranean Diet Adherence Score (MEDAS) score. Total polyphenol and total flavanol intakes were extrapolated from dietary data, using Phenol explorer database. Whole saliva was collected, and proteins were separated by SDS-PAGE. Salivary S-type cystatins were highly expressed in the group with medium adherence to MD, being positively correlated with wine intake in overweight individuals. The association between salivary amylase and MD adherence also depended on Body Mass Index (BMI), with a positive association only in normal weight individuals. Polyphenol intake was positively associated with S-type cystatins levels, particularly when flavanols were considered separately. These results show that saliva relationship with MD adherence depend on BMI, suggesting that normal weight and overweight individuals may have different salivary responses to diet. Moreover, these results reinforce the link between saliva and dietary polyphenols (flavanols) levels, leading to the hypothesis that salivary proteome can have a role in polyphenol-rich foods acceptance.

Chewing is a sensorimotor activity that aims to prepare food for swallowing, in which saliva intervenes, moistening food particles, assisting in bolus formation, enzymatic digestion, and swallowing. This study investigated the effect of chewing carrots of different shapes on salivary secretion and protein profiles using 2-DE gel electrophoresis. Fifteen participants chewed sliced or grated carrots, or parafilm (non-food control), in a crossover design, with saliva samples collected before and after mastication. The results showed significant differences in salivation and saliva composition when chewing carrots vs. the control, with sliced carrots inducing greater changes: 37 protein spots, including amylase and immunoglobulin spots, 9 protein spots, and 1 protein spot were significantly altered after chewing sliced carrots, grated carrots, and parafilm, respectively. Mastication combined with the sensory properties of food had a greater effect on saliva secretion and salivary protein levels than mastication alone. Among carrot shapes, the results suggest that harder food textures, which require more chewing effort, lead to more pronounced changes in salivary protein profiles. These findings contribute to the understanding of how food shape and texture influence salivation and salivary proteome dynamics, with potential implications for oral digestion, food-related sensory experiences, and the personalisation of diets for individuals with a compromised chewing capacity.

Restaurant menus have been shown to be important communicating and selling tools. In this online experimental study, we focused on the role of descriptive menus in influencing food choice and shaping customers’ perception of a traditional restaurant. Participants were randomly assigned to one of two menu conditions. In the intervention menu, five traditional dishes from the region of Alentejo (Portugal) were described using sensory (e.g., “fresh”) and authenticity (e.g., “genuine”) labels, while in the control condition, the dish name and its ingredients were presented with no further description. No significant differences were found regarding hedonic expectations, choice intention or willingness-to-pay for any of the individual dishes. However, participants in the intervention condition imagined the restaurant to have better service and ambience and serving tastier and fresher dishes. This study adds to the evidence suggesting the potential impact of menus in shaping consumers’ expectations of restaurants’ service quality, which in turn may affect how people perceive and assess their dining experience.