L-proline supplementation affects non-volatile flavour perception through oral microbiome metabolic pathways

Area of Science:

• Microbiology
• Sensory Science
• Nutritional Science

Background:

• L-proline, a non-essential amino acid, is metabolized by the oral microbiome.
• The oral microbiome's role in flavor perception is an emerging area of research.
• Understanding how dietary components influence the oral microbiome and sensory perception is crucial.

Purpose of the Study:

• To investigate the hypothesis that L-proline supplementation influences the oral microbiome.
• To determine if shifts in the oral microbiome affect non-volatile flavor perception.
• To identify the relationship between metabolic pathways, microbiome changes, and sensory outcomes.

Main Methods:

• A semi-trained sensory panel (n=20) assessed nine tastants using generalized labeled visual analogue scale (glVAS).
• Participants underwent a three-week protocol including a five-day L-proline supplementation phase.
• Shotgun sequencing and mixed-effects linear regression models were used to analyze microbiome and metabolic pathway data.

Main Results:

• Significant increase in menthol taste perception (p=0.011) during L-proline supplementation.
• Distinct beta diversity separation in metabolic pathways (p=0.008) observed during supplementation.
• Metabolic pathways, particularly those linked to protein synthesis, were stronger predictors of flavor perception than the microbiome itself.

Conclusions:

• L-proline supplementation alters oral microbiome metabolic pathways.
• These metabolic pathway alterations significantly impact non-volatile flavor perception, notably enhancing menthol taste.
• Metabolic pathways are identified as key mediators between L-proline intake and sensory experience.