There is more to wine flavour than just tastebuds

By Cyndal King

Wine tasting

Flavour is the most critical aspect of wine quality from a consumer’s perspective, but how much do we know about all the sources of flavour in wine?

Mango ParkerMango Parker

UniSA PhD Candidate, Mango Parker, has discovered another source of wine flavour that was previously overlooked: flavour precursors that release flavour in the mouth during wine tasting.

The Australian Wine Research Institute’s (AWRI) senior scientist made the finding through her study, which aims to establish how much the grape-derived compounds called glycosides impact the flavour of wine.

Parker has been developing a theory that wine flavour varies according to a person’s ability to detect the aroma released by glycosides breaking apart in the mouth.

”We wanted to discover why some people can taste certain flavours while others cannot,” she says.

“When we presented people with two glycosides with different flavours, some people could taste both, some could taste neither and some could taste one but not the other.

“We concluded that the main factor determining perception of flavour from glycosides is the ability to detect the released aroma, and not the oral microbiota or aroma release by saliva.”

Glycosides are flavour precursors that have no aroma or smell themselves but can release a burst of flavour when they break apart in the mouth through the action of the bacteria in saliva.

“They are formed in grape berries and are responsible for some of the distinctive aromas of wine, especially floral varieties like Muscat,” Parker says.

The glycosides must be able to break down in-mouth and release an odour in order to be sensed.

This method of flavour release does vary across individuals, contributing to an individual’s sensory perception and preferences towards wine flavour.

Parker’s research has shown that glycosides influence the chemistry of the wine, by releasing aroma, which then enhances flavour and contributes to a lingering aftertaste.

“These findings improve our fundamental understanding of how wine flavour can be generated and perceived – which has implications for viticulture (the science, study and production of grapes) and winemaking throughout the world,” Parker says.

Parker is working with the viticulture sector to minimise waste in wine production, using the solid remains of grapes, which are usually discarded (skin, pulp, seeds and stems) to extract glycosides to boost wine flavour.

Parker was also involved in the discovery of rotundone, the potent ‘black pepper’ aroma compound found in Shiraz.

Her work led to Parker being shortlisted for the 2019 Australian Women in Wine Awards in September in New York, for researcher/innovator of the year. 

More details about her research are available here.