Study of the grape glycosidic aroma precursors by crossing SPE-GC/MS, SPME-GC/MS and LC/QTOF methods

Questo studio ha permesso di raccogliere alcune informazioni sul profilo chimico della cultivar Vranac coltivata in Montenegro. L’uva ha mostrato di raggiungere un buon accumulo zuccherino

It is quite common nowadays to carry out analyses which allow to control the ageing of spirits that are aged in wood casks. Many control parameters have been previously studied, such as the concentration of different phenolic compounds or the Total Polyphenol Index, in order to better understand the ageing process of wood aged spirits. On the other hand, it is frequent to analyse as a physical parameter the colour of those spirit samples, by stating them as an array of three coordinates from various colour spaces as CIE L*a*b* or CIE L*C*H*.

Excessive fertilization of the vineyard leads to low quality grapes, increased costs and a negative impact on the environment. In order to establish an integrated management system aimed at a sustainable fertilization of the vineyards, nutritional reference levels were established. For this purpose, 30 representative vineyards of the Albariño variety were studied, in which soil and petiole analyses were carried out for two years and grape yield and quality at harvest were measured. In both years of study, soil pH, calcium, sodium and cation exchange capacity were positively correlated with calcium content and negatively correlated with manganese in grapes. Irrigated vineyards had higher levels of aluminium in soil and lower levels of calcium in petiole. Climatic conditions were very different in the years of the study. The year 2019 was colder than usual, in 2020 there was a marked water stress with high summer temperatures. This resulted in medium-high acidity in grapes in 2019 and low acidity in 2020, with sugar levels being similar both years. A very marked decrease in must amino nitrogen was observed in 2020, with ammonia nitrogen remaining stable. The correlation of acidity and sugar values in grapes with soil and petiole analysis data made it possible to establish reference levels for the nutritional diagnosis of the Albariño variety in this region. Based on these results, an easy-to-use TIC application is currently being created for grapegrowers, aimed at improving the sustainability of the vineyard through reasoned fertilization. This study has now been extended to other Galician vine varieties.

Climate changes have important consequences in viticulture, heat waves accompanied by periods of drought are encountered more and more frequently. This study aims to evaluate the single and combined effect of water deficit and high temperatures on the thiol precursors biosynthesis in Sauvignon blanc grapes. For this purpose, a protocol has been developed for the cultivation of berries on a solid substrate. The berries, collected at three different times starting from veraison and grown in vitro, were subjected to 4 different treatments: control (C), water stress (WS), heat stress (HS), combined water and heat stress (WSHS). Water stress was simulated by adding abscisic acid to the culture medium, while different temperatures, respectively 25°C and 35°C, were managed with two illuminated climatic chambers.

Visual clarity in wines is crucial for commercial purposes [1]. Potential protein haze in white wines remains a constant concern in wineries, commonly addressed using bentonite [2].