Kokumi chemistry for rich-tasting sparkling wines

‘Rich’ and ‘full-bodied’ are terms that people often use to describe the taste of wine. They are also the properties that kokumi compounds bring to foods like mature Gouda cheese, although scientists haven’t widely explored them in wines. In the American Chemical Society’s Journal of Agricultural and Food Chemistry, researchers now connect the dots and report 11 probable kokumi compounds in sparkling wines.

Kokumi is often confused with the better-known term umami. Umami is a savoury, meaty flavour and is one of the basic tastes, along with sweet, sour, bitter and salty. However, kokumi is not a taste or flavour on its own — it’s a combination of compounds that work together to enhance flavours and provide richness.

Previously, researchers have shown that glutathione and several other short peptides impart a kokumi sensation in foods and drinks such as garlic, onions, beans, cheese and beer, but these compounds had not been investigated in wine. So Fulvio Mattivi, Luca Dellafiora and colleagues set out to do so.

The researchers found that five vintages of Italian Trentodoc sparkling wine contain a mixture of 50 short peptides that could possibly be the source of the wine’s kokumi properties.

Next, they discovered that 11 of the 50 kokumi candidates interacted with computer-simulated human calcium-sensing receptors in a way that’s similar to other known kokumi compounds.

When team members surveyed another 34 Trentodoc wines, they verified that these 11 compounds were indeed representative of this style of Italian sparkling wine.

Finally, wine-tasting experts confirmed Gly-Val — one of the 11 candidates — as a probable kokumi compound because it enhanced flavour when added to wine samples.

The team said that further studies are needed, but this report represents the first step toward describing the molecular basis of the kokumi sensation in wines.

“In light of these results, it will be necessary to further investigate the role of winemaking technology and yeasts in releasing kokumi oligopeptides derived from the grape proteins, bringing further richness to classic sparkling wines and extending the investigation to other wine styles as well,” Mattivi said.

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