BORDEAUX RED WINES WITHOUT ADDED SULFITES SPECIFICITIES: COMPOSITIONAL AND SENSORY APPROACHES TOWARDS HIGHLIGHTING AND EXPLAI-NING THEIR SPECIFIC FRUITINESS AND COOLNESS

Abstract

With the development of naturality expectations, wines produced without any addition of sulfur dioxide (SO₂) become very popular for consumers and such wines are increasingly present on the market. Recent studies also showed that Bordeaux red wines without added SO₂ could be differentiated from a sensory point of view from similar wines produced with SO₂¹. Thus, the aim of the current study was to charac-terize from a sensory point of view, specific aromas of wines without added SO₂ and to identify com-pounds involved.

First, sensory profile were established for wines produced from the same merlot grapes with or wit-hout SO₂ addition throughout all winemaking process². This led to demonstrate that wine without added SO₂ was perceived differently than the wine with added SO₂ with a specific fruity aroma and a higher coolness. Moreover, to validate that presence of free SO₂ was not only at the origin of these differences, triangle tests were also performed from these wines.

In a second step, targeted analyses were performed on compounds known to be impacted by SO₂ and/or with specific impact on fruity aroma. Thus, acetaldehyde, diacetyl, and methyl salicylate, previously identified by a sensory target approach³, were studied. These quantification approaches allowed to ob-serve that wines without added SO₂ presented free acetaldehyde, higher concentrations in methyl sali-cylate and lower concentrations of free and total diacetyl. Based on these results, sensory characterization of these compounds in wines without added SO₂, and considering the impact of SO₂ were done using sensory profile. This allowed to show that presence of methyl salicylate, acetaldehyde and/or free SO₂ modified perception of coolness, whereas diacetyl and methyl salicylate modified fruity aroma.

Finally, experimental wine produced from the same grapes respectively with and without SO₂ addition were supplemented, according to their compositional specificities, with SO₂ and diacetyl for the wine without added SO₂ and with methyl salicylate for that one with added SO₂. These two supplemented wines were compared by triangle test and were perceived differently, thus underlined that differences between red wine produced with and without added SO₂ from Bordeaux involve other compounds than those considered here and suggests that further investigations are needed.