Application of Hyper Spectral Imaging for early detection of rachis browning in table grapes

Hanseniaspora vineae (Hv) is a fermenting non-Saccharomyces yeast that compared to Saccharomyces cerevisiae (Sc) present some peculiar features on its metabolism that make it attractive for its use in wine production. Among them, it has been reported a faster yeast lysis and release of polysaccharides, as well as increased ß-glucosidase activity. Hv also produces distinctive aroma compounds, including elevated levels of fermentative compounds such as ß-phenylethyl acetate and norisoprenoids like safranal. However, it is known for its high nutritional requirements, resulting in prolonged and sluggish fermentations, even when complemented with Sc strain and nutrients.

Grapevine leaves are known to contain different polyphenols such as flavonols, catechins and stilbenes, which are known to act as main contributors for plant defense against pathogens (1). While the composition for some major cultivars has been studied, there is lack of systematic comparison about the content of these compounds in the wide ecodiversity of Vitis vinifera cv. Recent advances in Mass Spectrometry-based Metabolomics allow a wider and more sensitive description of these polyphenols, as instance of those present in leaves (2). Such information could help to better explain leaf traits regarding the development of the leaf or to the plant tolerance to a pathogen. Moreover, these compounds offer appealing applications for human health due to their antioxidant activities.

Several studies have tried to develop different methods to study the photodegradation of wine in an accelerated way, trying to elucidate the effect of light on the wine compounds[1]. In a previous study, our team developed a chamber that speeds up the photodegradation of rosé wine[2]. In the present work we have tried to establish a correlation between irradiation times in accelerated conditions and the natural exposure to the cycles of light that usually exist in markets or at home.

The table grape industry in Europe is undergoing significant changes. For instance, in Italy, the national register of vine varieties was established in 1969, and since then, many varieties of table grapes have been registered. In the first thirty years, from 1969 to 1999, 62 seeded and 24 seedless varieties were registered. In the subsequent period, from 2000 to the present day, 23 seeded varieties and 99 seedless varieties were registered.

The goal of this work was to determine the spatial variability of terroir using the isotope composition of wine. Carbon (δ13C) and oxygen (δ18O) stable isotope composition was measured in wines from Tempranillo (Vitis vinifera L.) vineyard, located in Rioja Appellation (Spain). Stable isotope composition, leaf area, vigour, yield components, grape and wine composition were determined in a grid of 85 geo-referenced points, that was drawn across the 5 ha vineyard area