A mechanistic investigation of H/D scrambling processes in flavonoids

Grapevine downy mildew, caused by Plasmopara viticola, is a devastating disease worldwide. Most commercially important cultivars of the European grapevine are highly susceptible and therefore require the recurrent application of synthetic fungicides to control the disease, copper being the most frequently used. However, with European Union goals to lower their usage, there is a need to develop innovative and sustainable strategies. In this respect, seaweeds have proven to have great potential as phytosanitary agents, in addition to promoting plant growth and stress-tolerance.

AIM AND METHODS: Grape withering is one of the key steps in the production of the most renowned red wines of the Valpolicella area, namely Amarone and Recioto. This practice, which was already used since Roman times, entails important modifications in grape composition and in the chemical and sensorial characteristics of the corresponding wines, especially in terms of aromatic profile. The aim of this research is evaluating the aromatic evolution during grape withering of the three main varieties used in Valpolicella wines: Corvina, Corvinone and Rondinella.Samples of the three varieties were analyzed at harvest and at different stages of withering, namely10%, 20% and 30% of weight loss. Free and glycosidically bound compounds were extracted and analyzed using Gas Chromatography- Mass Spectrometry (GC-MS). RESULTS: For all the samples the data were normalized to eliminate the effect of concentration due to grape dehydration. Terpene content and evolution varied considerably in relationship to grape variety. Corvinone was richer in cyclic terpenes (including phellandrene, limonene, and cymene) and they decreased during withering.

Quercetin (Q), a phenolic compound released from grape skins during red wine maceration, has been identified as a source of instability in bottled wines, particularly Sangiovese, due to crystallisation. This phenomenon represents an economic challenge for producers and affects wine clarity and consumer perception.

Soil mulching is an interesting strategy to reduce soil evaporation, assist in weed control, improve soil structure and organic content, increase soil water infiltration, and decrease diurnal temperature fluctuations

The aim of this work was to study winemaking alternatives that will optimize the quality of the Tannat wines, taking advantage of the grape’s oenological potential.