Evoluzione stagionale delle temperature ed andamento della maturazione nel vitigno Aglianico: risultati di un quadriennio di osservazioni in Campania

Due to altered climatic conditions, grape berry sunburn has become one of the main challenges in contemporary viticulture.

Elemental sulfur is a fungicide used by grape growers to control the development of powdery mildew, caused by the fungus Erysiphe necator. This compound is effective, cheap and has a low toxicity with no withholding period recommended. However, high levels of S0 residues in the harvested grapes can lead to the formation of reductive sulfur compounds that can impart taints and faults to the wine. Hydrogen sulphide (H2S) is a very volatile and unpleasant sulfur compound which formation is connected to high residues of S0 in juice (10 – 100 mg/L).

The black box of taste is getting unlocked. The starting point is to distinguish taste from tasting. Consider taste as a product characteristic; tasting is a sensorial activity. Consequently, taste can be studied on a molecular level and therefore be assessed more objectively, whilst tasting is a human activity and by definition subjective.

1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN) is a controversial aroma component found in Riesling wines. It belongs to the family of C13-norisoprenoids and is mainly associated with kerosene/petrol notes. TDN can add complexity to the wine aroma at medium – low concentrations and deteriorate the wine bouquet when its content is high. No TDN aromas are usually perceived in young Riesling wines, but they can appear after several years of aging due to the gradual formation of TDN. Management of TDN in Riesling wines is an actual task, since global warming can promote formation of this compound and compromise the aromatic composition of wine. Therefore, the aim of the current work was, firstly, to study the sensory particularities of TDN in Riesling wine at various concentrations. Secondly, to investigate the ability of bottle closures to absorb (scalp) TDN from Riesling wine under various storage conditions. These studies also include the comparative assessment of our findings with previously published data. METHODS: sensory analysis, GC-MS (SBSE), HPLC,1H-NMR and other methods related to the synthesis and determination of TDN. RESULTS: First of all, the method of the synthesis of highly purified TDN (95% and 99.5%) was optimized [1].

Acetaldehyde is a volatile carbonyl compound synthetized by yeast during alcoholic fermentation, but it can also be formed by oxidation of ethanol during wine aging [1]. At low concentration, it enhances the fruity aroma, however, at higher levels, it can generate the appearance of notes of bruised and rotten apple [2]. From a chemical point of view, acetaldehyde is a reactive low-