Characterization of tongue dorsum microbiome in wine tasters

Microbial β C-S Lyases: Enzymes with Multifaceted Roles in Flavor Generation

β C-S lyases (β-CSLs; EC 4.4.1.8) are enzymes catalyzing the dissociation of β carbon-sulfur bonds of cysteine S-conjugates to produce odorant metabolites with a free thiol group. These enzymes are increasingly studied for their role in flavor generation in a variety of food products, whether these processes occur directly in plants, by microbial β-CSLs during fermentation, or in the mouth under the action of the oral microbiota. Microbial β-CSLs react with sulfur aroma precursors present in beverages, vegetables, fruits, or aromatic herbs like hop but also potentially with some precursors formed through Maillard reactions in cooked foods such as meat or coffee. β-CSLs from microorganisms like yeasts and lactic acid bacteria have been studied for their role in the release of polyfunctional thiols in wine and beer during fermentation. In addition, β-CSLs from microorganisms of the human oral cavity were shown to metabolize similar precursors and to produce aroma in the mouth with an impact on retro-olfaction. This review summarizes the current knowledge on β-CSLs involved in flavor generation with a focus on enzymes from microbial species present either in the fermentative processes or in the oral cavity. This paper highlights the importance of this enzyme family in the food continuum, from production to consumption, and offers new perspectives concerning the utilization of β-CSLs as a flavor enhancer.

Unlocking Flavor Potential Using Microbial β-Glucosidases in Food Processing

Aroma is among of the most important criteria that indicate the quality of food and beverage products. Aroma compounds can be found as free molecules or glycosides. Notably, a significant portion of aroma precursors accumulates in numerous food products as nonvolatile and flavorless glycoconjugates, termed glycosidic aroma precursors. When subjected to enzymatic hydrolysis, these seemingly inert, nonvolatile glycosides undergo transformation into fragrant volatiles or volatiles that can generate odor-active compounds during food processing. In this context, microbial β-glucosidases play a pivotal role in enhancing or compromising the development of flavors during food and beverage processing. β-glucosidases derived from bacteria and yeast can be utilized to modulate the concentration of particular aroma and taste compounds, such as bitterness, which can be decreased through hydrolysis by glycosidases. Furthermore, oral microbiota can influence flavor perception by releasing volatile compounds that can enhance or alter the perception of food products. In this review, considering the glycosidic flavor precursors present in diverse food and beverage products, we underscore the significance of glycosidases with various origins. Subsequently, we delve into emerging insights regarding the release of aroma within the human oral cavity due to the activity of oral microbial glycosidases.

Beyond the Bottle: Exploring Health-Promoting Compounds in Wine and Wine-Related Products-Extraction, Detection, Quantification, Aroma Properties, and Terroir Effects

Health-promoting compounds in wine and wine-related products are important due to their potential benefits to human health. Through an extensive literature review, this study explores the presence of these compounds in wine and wine-related products, examining their relationship with terroir and their impact on the aromatic and flavor properties that are perceived orally: sunlight exposure, rainfall patterns, and soil composition impact grapevines' synthesis and accumulation of health-promoting compounds. Enzymes, pH, and the oral microbiome are crucial in sensory evaluation and perception of health promotion. Moreover, their analysis of health-promoting compounds in wine and wine-related products relies on considerations such as the specific target compound, selectivity, sensitivity, and the complexity of the matrix.

Salivary microbial profiles associate with responsiveness to warning oral sensations and dietary intakes

Oral microbiota-host interactions are gaining recognition as potential factors contributing to interindividual variations in taste perception. However, whether such possible links imply specific bacterial co-occurrence networks remains unknown. To address this issue, we used 16 s rRNA gene sequencing to profile the salivary microbiota of 100 healthy individuals (52 % women; 18-30 y/o), who provided hedonic and psychophysical responses to 5 liquid and 5 solid commercially-available foods, each chosen to elicit a target sensation (sweet, sour, bitter, salty, pungent). The same cohort also completed several psychometric measures and a 4-day food diary. Unsupervised data-driven clustering of genus-level Aitchison distances supported the existence of two salivary microbial profiles (CL-1, CL-2). While CL-1 (n = 57; 49.1 % women) exhibited higher α-diversity metrics and was enriched in microbial genera assigned to the class Clostridia (e.g., Lachnospiraceae_[G-3]), CL-2 (n = 43; 55.8 % women) harbored greater amounts of taxa with potential cariogenic effects (e.g., genus Lactobacillus) and significantly lower abundances of inferred MetaCyc pathways related to the metabolic fate of acetate. Intriguingly, CL-2 showed enhanced responsiveness to warning oral sensations (bitter, sour, astringent) and a higher propensity to crave sweet foods or engage in prosocial behaviors. Further, the same cluster reported habitually consuming more simple carbohydrates and fewer beneficial nutrients (vegetable proteins, monounsaturated fatty acids). In summary, while the mediating role of participants' baseline diet on findings can not be definitively excluded, this work provides evidence suggesting that microbe-microbe and microbe-taste interactions may exert an influence on dietary habits and motivates further research to uncover a potential "core" taste-related salivary microbiota.