Environmental and viticultural practice effects on the phenolic composition of grapes: impact on wine sensory properties

As an essential element for grapevine development and yield, nitrogen is also involved in the winemaking process and largely affects wine composition. Grape must amino nitrogen deficiency affects the alcoholic fermentation kinetics and alters the development of wine aroma precursors. It is therefore essential to control and optimize nitrogen use efficiency by the plant to guarantee suitable grape nitrogen composition at harvest. Understanding the impact of environmental conditions and cultural practices on the plant nitrogen metabolism would allow us to better orientate our technical choices with the objective of quality and sustainability (less inputs, higher efficiency). This trial focuses on the impact of crop limitation – that is a common practice in European viticulture – on nitrogen distribution in the plant and particularly on grape nitrogen composition. A wide gradient of crop load was set up in a homogeneous plot of Chasselas (Vitis vinifera) in the experimental vineyard of Agroscope, Switzerland. Dry weight and nitrogen dynamics were monitored in the roots, trunk, canopy and grapes, during two consecutive years, using a 15N-labeling method. Grape amino nitrogen content was assessed in both years, at veraison and at harvest. The close relationship between fruits and roots in the maintenance of plant nitrogen balance was highlighted. Interestingly, grape nitrogen concentration remained unchanged regardless of crop load to the detriment of the growth and nitrogen content of the roots. Meanwhile, the size and the nitrogen concentration of the canopy were not affected. Leaf gas exchange rates were reduced in response to lower yield conditions, reducing carbon and nitrogen assimilation and increasing intrinsic water use efficiency. The must amino nitrogen profiles could be discriminated as a function of crop load. These findings demonstrate the impact of plant balance on grape nitrogen composition and contribute to the improvement of predictive models and sustainable cultural practices in perennial crops.

La pratique de la délimitation des aires des Appellations d’Origine Contrôlées françaises découle de la définition de la notion de terroir en Appellation

Acidity is often touted as a predictor of wine ageability, though surprisingly few studies have systematically investigated the chemical basis for this claim.

AIM: Cross-over applications are an emerging technological approach in food microbiology where a microorganism from one traditional specific fermentation process is used to improve quality and safety in another agri-food production/chain (Dank et al., 2021). A complex microbial diversity is found in association with fermentation in wine, including Saccharomyces, non-Saccharomyces and malolactic bacteria,  all microorganisms versatile in terms of enological utilisation (Tempère et al., 2018). Here, we propose a systematic literature review highlighting the existing trends and possible future applications related to cross-over exploitation of wine-related microbiota. 

Micropropagation is an important alternative to conventional methods of plant propagation. The objective of this study was to optimize a protocol for in vitro micropropagation of selected grapevine hybrids (H19 and H20) that are included in our breeding program. For the sprouting initiation experiment, nodal cuttings with only one axillary bud from two hybrids were separated, disinfected, and cultivated in 50% Murashige Skoog nutrient medium (½ MS) and Woody Plant Medium (WPM), adding 4.4 µM benzyladenine (BA) in both mediums.