Introduction: Over the past years, several efforts have been made to formulate and develop plant-based substitutes of animal-based products in response to environmental changes, health issues and animal welfare. However, plant-based protein poses several challenges to product sensory characteristics, especially appearance, flavor, and texture. Despite this, current literature data have mainly reviewed nutritional, technological, and sustainability aspects of plant-based products with limited concerns on perceived sensory properties and perceptive barriers to consumption related to each specific substitute. To fill this literature gap, this systematic review aims to provide an up-to-date overview of the perceptive determinants of consumers' acceptance of plant-based substitutes of animal-origin products, including meat, dairy, fish and eggs analogs, with emphasis on product's intrinsic properties: appearance, smell, taste, and texture. Moreover, age-, gender-, and cultural-related differences in the appreciation/rejection of plant-based substitutes of animal-origin products were investigated.Methods: The systematic analysis of the literature consulting Web of Science (Core Collection) and Scopus databases retrieved 13 research articles on meat, 26 on dairy, and two on fish and eggs analogs.Results and discussion: Results showed that all sensory dimensions are influenced by the replacement of animal proteins with those of vegetable origin. However, the relative importance of appearance, odor, taste, and texture varied according to plant-based analogs category and mitigatory processing strategies to mask unpleasant sensory properties have been suggested for each category. Dairy analogs mainly suffer of aromas and flavors imparted by the raw materials, while both meat and dairy analogs have texture challenges. Meat analogs lack of juiciness, elasticity and firmness, while dairy analogs require uniform, creamy and thick texture. Moreover, very few studies analyzed the product's perception, considering age- and gender-related differences or cross-national/cultural differences. Future research should be addressed to specific product categories such as fish and eggs analogs as well as specific population targets including children and the elderly and consumers from developing countries.

Fairly poor data are available on the relationship between taste perception, food preferences and oral microbiota. In the present study, we investigated the hypothesis that subjects with higher responsiveness to 6-n-propylthiuracil (PROP) might be characterized by a different taste sensitivity and tongue microbiota composition. Indeed, the bacterial metabolism may modulate/enhance the concentration of tastants near the taste receptors, modifying taste perception through a sensorial adaptation mechanism or by a broad range of microbial metabolic pathways. The detection thresholds of sweet, sour, salty and bitter, the Fungiform Papillae Density (FPD) and the composition of bacteria lining the tongue were determined in Supertasters (high PROP responsiveness, ST) and Non-tasters (low PROP responsiveness, NT). An important inter-individual variability was found for all taste stimuli and FPD between the two groups, with NT subjects showing significant higher threshold values and a lower FPD than with STs. We found five bacterial genera whose relative abundances were significantly higher in STs than NTs. This study opens new avenues of research by highlighting associations between parameters usually studied independently.

The Mediterranean diet (MD) is associated with many health benefits. The association between the MD and food neophobia (FN) is still unexplored in adults. The present cross-sectional study was aimed to explore the relationships between adherence to the MD, FN, and sociodemographic variables in a large Italian cohort. Familiarity and frequency use (FFI) of prototypical and non-prototypical Mediterranean foods were used to calculate a new adherence index: the Italian Taste Mediterranean Index (ITMI). The FFI of all Mediterranean foods increased with age, while butter, soft drinks, red/cured meat, and sweets were more common in younger people. Accordingly, ITMI increased with age (F_2,2384 = 54.11; p < 0.0001). Women recorded a higher ITMI (6.70) than men (6.10). Individuals with high FN showed higher FFI for soft drinks and sweets and lower ones for most typical MD foods, than individuals with low FNs. A decrease of ITMI was recorded with the increase of the FN(F_2,2384 = 22.84; p < 0.0001). With ageing, ITMI increased even in individuals with a high FN. The results suggest that FN may negatively affect adherence to the MD, lowering its potential health benefits, in the adult population. Monitoring of food habits, dietary education, and anxiety management, may be valuable tools to control FN and support the adherence to the MD.