Piloting grape ripening in a global warming scenario: feasible techniques are available

Several classes of flavonoids, such as anthocyanins, flavonols, flavanols and flavones, undergo a slow H/D exchange on aromatic ring A, leading to full deuteration at positions C(6) and C(8). Within the flavanol class, H-C(6) and H-C(8) of catechin and epicatechin are slowly exchanged in D2O to the corresponding deuterated analogues; even quercetin, a relevant flavonol representative, shows the same behaviour in a D2O/DMSOd6 1:1 solution. Detailed kinetic measurements of these H/D scrambling processes are here reported by exploiting the time-dependent changes of their peak areas in the 1H-NMR spectra taken at different temperatures. A unifying reaction mechanism is also proposed based on our detailed kinetic observations, even taking into account pH and solvent effects. Molecular modelling and QM calculations were also carried out to shed more light on several molecular details of the proposed mechanism.

The local wine as an area identified and recognized is a complex socio-historical reality that calls an effort of observation and theoretical reflection using various social sciences

Plant roots fulfil important functions as they are responsible for the acquisition of water and nutrients, for anchorage and stability, for interaction with symbionts and, in some cases, for the storage of carbohydrates. These functions are associated with the Root System Architecture (RSA, i.e. the form and the spatial arrangement of the roots in the soil). The RSA results from several biological processes (elongation, ramification, mortality…) genetically determined but with high structural plasticity.

During alcoholic fermentation, acetaldehyde is the carbonyl compound quantitatively the most produced by yeasts after ethanol. The dynamics of acetaldehyde production can be divided into 3 phases. Early formation of this compound is observed during the lag phase at the beginning of fermentation before any detectable growth [1].

Controlling the speed of alcoholic (AF) and malolactic (MLF) fermentations in wine can be an important challenge for the production of certain short rotation wines for entry-level market segments. Immobilization techniques for Saccharomyces cerevisiae and Œnococcus œni, the microorganisms responsible for these fermentations, are widely studied for industrial applications. Indeed, these processes allow to accumulate biomass and thus to increase cell densities inducing high fermentation velocities. Recent works have shown the performance of MLF carried out with biofilms of O. œni, immobilized on various supports in a rich medium (MRSm: modified MRS broth with malic acid and fructose).