Stimulation of saliva affects the release of aroma in wine; a study of microbiota, biochemistry and participant origin

Saliva influences the release of aroma in the oral cavity. The composition of human saliva varies depending on stimulation; however, the compositional differences of saliva caused by stimulation and their influences on aroma release have not been fully evaluated. Humans display strong sensory preference for different aromas, with preference linked to country of origin, culture and personal history, yet how salivary composition is implicated in aroma release is not understood. In this study, we recruited healthy adults, of which 15 were Australian and 15 Chinese. Three types of saliva were collected from each participant: before, during, and after salivary stimulation. Ninety collected salivary samples were characterised by flow rate, total protein concentration, esterase activity and microbiome composition by full-length 16S rRNA gene sequencing. The saliva samples were mixed with wine to investigate the differences in released volatiles by headspace solid-phase microextraction gas chromatography - mass spectrometry. Differences in salivary composition and specific wine volatiles were found between Australian and Chinese participants, and amongst the three stimulation stages. Differential species were identified and significant correlations between the relative abundance of 3 bacterial species and 10 wine volatiles were observed. Our results confirm the influence of participant geographic origin and stimulation on salivary composition. Understanding the interactions of salivary components, especially salivary bacteria, on the release of aroma from wine allows nuanced appreciation of the variability of flavour perception in wine consumer groups. Highlights ### Competing Interest Statement The authors have declared no competing interest.