WAC 2022 banner
IVES 9 IVES Conference Series 9 WAC 9 WAC 2022 9 2 - WAC - Posters 9 Impact of toasting on oak wood aroma: creation of an oak wood aroma wheel

Impact of toasting on oak wood aroma: creation of an oak wood aroma wheel

Abstract

The impact of toasting process to produce aroma from oak wood intrinsic composition is well documented. It is admitted that such complexity contribute to the wine quality after barrel ageing. Despite our knowledge on the molecular identification of aroma impact compounds of oak wood, little research have been carried out, on a sensory level, on the aroma diversity of toasted oak wood. For this reason, this work aims at creating an aroma wheel to describe and categorize the complexity of aroma descriptors based on a lexical analysis. In a first experiment, a free association task was conducted to identify individual mental representations of oak wood samples. For that, a panel (13 persons from Seguin Moreau cooperage and wine makers) was selected to write down, via an online survey, the descriptors that come to mind to describe oak wood aroma according to a specific toasting intensity (non-toasted or toasted at 160 °C, 180 °C or 240 °C for 30 min). Data obtained were analyzed according to a semantic analysis to determine citation frequency of each descriptor. Synonyms or descriptors linked to the same lexical field were gathered, reducing the number of descriptors from 215 to 83. Citation frequencies were evaluated in order to identify the most relevant descriptors used by the panel (f>0.02). After that, a categorization of samples and descriptors was performed to highlight sensory boundaries among them. Samples categorization was performed by a correspondence analysis (AFC) applied to citation frequencies while words categorization was achieved by a sorting using a consensus approach. Finally, seven main descriptors were obtained, allowing distinguish oak wood samples depending on their toasting intensity: non-toasted oak wood was categorize with ‘fresh wood’ and ‘vegetable’ descriptors while highly toasted oak wood was categorize with ‘roasting’, ‘spices’ and ‘smoked’ descriptors, for example. Subsequently, a conventional profiling was performed by a trained panel (13 persons from the laboratory team) on oak wood samples (different toasting process). ANOVA analysis revealed the relevance of defined descriptors to describe oak wood aroma during its toasting. This work permits to purpose a visual tool to describe oak wood aroma. It provides specific terminology to describe the sensory changes during toasting process. This aroma wheel is intended to meet academic and professional needs for the quality assessment of oak wood aroma based on sensory analysis.

DOI:

Publication date: June 13, 2022

Issue: WAC 2022

Type: Article

Authors

Marie Courregelongue, Marie Courregelongue, Alexandre Pons

Presenting author

Marie Courregelongue – UMR ŒNOLOGIE (OENO), ISVV, UMR 1366, Université de Bordeaux, INRAE, Bordeaux INP, Villenave d’Ornon, France & Tonnellerie Seguin Moreau, Merpins, France

Tonnellerie Seguin Moreau, Merpins, France | UMR ŒNOLOGIE (OENO), ISVV, UMR 1366, Université de Bordeaux, INRAE, Bordeaux INP, Villenave d’Ornon, France & Tonnellerie Seguin Moreau, Merpins, France

Contact the author

Keywords

oak wood, toasting process, sensory approach, aroma wheel

Tags

IVES Conference Series | WAC 2022

Citation

Related articles…

Mobile device to induce heat-stress on grapevine berries

Studying heat stress response of grapevine berries in the field often relies on weather conditions during the growing season. We constructed a mobile heating device, able to induce controlled heat stress on grapes in vineyards. The heater consisted of six 150 W infrared lamps mounted in a profile frame. Heating power of the lamps could be controlled individually by a control unit consisting of a single board computer and six temperature sensors to reach a pre-set temperature. The heat energy applied to individual berries within a cluster decreases by the squared distance to the heat source, enabling the establishment of temperature profiles within individual clusters. These profiles can be measured by infrared thermography once a steady state has been reached. Radiant flux density received by a berry depending on the distance was calculated based on a view factor and measured lamp surface temperature and resulted to 665 Wm-2 at 7cm. Infrared thermography of the fruit surface was in good agreement with measurements conducted with a thermocouple inserted at epidermis level. In combination with infrared thermography, the presented device offers possibilities for a wide range of applications like phenotyping for heat tolerance in the field to proceed in the understanding of the complex response of plants to heat stress. Sunburn necrosis symptoms were artificially induced with the aid of the device for cv. Bacchus and cv. Sylvaner in the 2020 and 2021 growing season. Threshold temperatures for sunburn induction (LT5030min) were derived from temperature data of single berries and visual sunburn assessment, applying logistic regression. A comparison of threshold temperatures for the occurrence of sunburn necrosis confirmed the higher susceptibility of cv. Bacchus. The lower susceptibility of cv. Sylvaner did not seem to be related to its phenolic composition, rendering a thermoprotective role of berry phenolic compounds unlikely.

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

Influence of weather and climatic conditions on the viticultural production in Croatia

The research includes an analysis of the impact of weather conditions on phenological development of the vine and grape quality, through monitoring of four experimental cultivars (Chardonnay, Graševina, Merlot and Plavac mali) over two production years. In each experimental vineyard, which were evenly distributed throughout the regions of Slavonia and The Croatian Danube, Croatian Uplands,

The modification of cultural practices in grapevine cv. Syrah, does it modify the characteristics of the musts?

The work shows the results of a year of experimentation (2020) in a Syrah variety vineyard in La Roda (Castilla-La Mancha, Spain). The trial approach was on a randomized block design with two factors: Irrigation (I) and Pruning (P).
Irrigation schedules were adjusted to apply amounts close to 1,500 m3/ha. With this provision, 2 different irrigation treatments were proposed: I1) Start of irrigation from pea-sized grape to post-harvest (providing at least 20 % of the total amount of irrigation water to be provided post-harvest); I2) Start of irrigation from pea-sized grape to harvest (usual irrigation practice in the study area). Pruning was proposed with two treatments, one at the end of January (P1), which is pruning on a conventional date; and P2) pruning carried out at the beginning of budding. In total, 4 repetitions were designed with 4 elementary plots, each one of them representing one of the proposed treatments (I1P1; I1P2; I2P1; I2P2). In total, 16 plots were worked on and each elementary plot consisted of 30 strains, distributed in 3 lines.
The productive response was evaluated with the yield results of the harvest harvested at 23 ºBrix. The qualitative response was measured in the musts through the indices of technological (acidity, pH and potassium) and phenolic maturity and aromatic compounds in free and glycosylated fractions. The treatments tested had, in general, an effect on the different variables analyzed.

Local ancient grapevine cultivars to face future viticulture

Among the different strategies to cope with the negative impacts of climate change on viticulture, the exploitation of genetic diversity is one of the most promising to adapt to new conditions and maintain wine production and quality. One of the biggest concerns in the context of climate change is to improve water use efficiency (WUE). In this way, the use of genotypes that present a better response to drought and high WUE is a key issue. In this work, physiological performance analysis was conducted to compare the water deficit stress (WDS) responses of local and widespread grapevines cultivars. Leaf gas exchange, water use efficiency (WUE) at different levels (leaf and long-term WUE (∆13C)), leaf osmotic adjustment and other water relations parameters were determined in plants under well-watered and WDS conditions alongside assessment of the levels of foliar hormones concentrations. Results denote that local cultivars displayed better physiological performance under WDS as compared to the widely-distributed ones. he results corroborate the hypothesis that better stomatal control allows increasing leaf WUE under drought as occurred in the local Callet cv.; but the minority local cultivar Escursac cv. showed high WUE under both treatments. In this case, high WUE can be related to maintaining higher photosynthetic activity under drought. The different mechanisms underlying the better performance under WDS and high WUE of minority local cultivars are discussed.