Biotechnological tools to preserve the complexity and the fruity quality of Bordeaux red wines

Abstract

The production of wine is closely linked to complexity and quality (1). In the context of climate change, changing consumer habits and economic pressure on the wine industry, identifying the factors that influence aromatic complexity is crucial for improving wine quality. There is concern within the wine industry that the widespread use of single commercial yeast strains may reduce wine complexity and lead to standardization. The literature reports that interactions among multiple yeast species can produce wines with distinct chemical profiles (2). However, are such wines truly more complex in terms of their sensory properties? In this context, the olfactory and molecular profile of Merlot red wines from Bordeaux produced using different oenological techniques were studied. An original sensory analysis approach, focusing on the concept of complexity (3) and evaluating the fruity expression, was conducted alongside GC/MS analysis of targeted volatile compounds. To assess the link between microbiological diversity and aromatic complexity, alcoholic fermentations were carried out using several S. cerevisiae strains, either alone or in combination, and their molecular and sensory impact on the wines was analysed. Initial results show that, while each yeast strain contributes to a unique aromatic and sensory profile, using a mixed culture of S. cerevisiae strains for fermentation does not necessarily result in an increased perceived complexity or fruity notes. These observations put into perspective the commonly held belief that microbiological diversity leads to sensory complexity. In addition to this main study, the use of β-glucosidase-based enzyme preparation in Bordeaux white and red wines was studied in order to evaluate its impact on the olfactory complexity and fruity expression. Recently, scientists revealed that adding certain monoterpenic and C13-norisoprenoid compounds to a red wine, initially described as having cooked fruit aromas, increases the fresh fruity notes (4). Numerous studies have been conducted on the use of enzymes to release these compounds in white wine, but very little attention has been paid to red wines. These results will enable a critical discussion of the oenological levers that can be used to modulate the aromatic complexity and the fruity expression of Bordeaux red wines in the context of climate change.

References

1. Tempere S.; Marchal A.; Barbe J.-C.; Bely M.; Masneuf-Pomarede I.; Marullo P. & Albertin W. (2018) The complexity of wine: clarifying the role of microorganisms. Applied Microbiology and Biotechnology, 102(9): 3995-4007.

2. Howell K.S.; Cozzolino D.; Bartowsky E.J.; Fleet G.H. & Henschke P.A. (2006) Metabolic profiling as a tool for revealing Saccharomyces interactions during wine fermentation. FEMS Yeast Research, 6: 91–101.

3. Maraboli, M. M.; Masters, O.; Araujo, L. D. & Valentin, D. (2020). Perception of quality and complexity in wine and their links to varietal typicality: An investigation involving Pinot noir wine and professional tasters. Food Research International, 137, 109423.

4. Garbay, J.; Cameleyre, M.; Riquier, L.; Barbe, J. C. & Lytra, G. (2023). Development of a new method for the quantitative analysis of aroma compounds potentially related to the fruity aroma of red wines. Journal of Agricultural and Food Chemistry, 71(35), 13066-13078.