Revisiting the effect of subsurface irrigation and partial rootzone drying on canopy size and yield of Cabernet Sauvignon using remote sensing techniques

To make some particular wine styles (e.g., Amarone), grapes are harvested and stored in dehydrating rooms before vinification, in a process called withering

​For several years, the chemistry of taste has aroused high interest both from academics and industrials. Plant kingdom is a rich and reliable source of new taste-active compounds. Many sweet, bitter or sour molecules have been identified in various plants [1]. They belong to diverse chemical families and their sensory properties are strongly affected by slight structural modifications. As a consequence, the investigation of natural taste-active products in a given matrix appears as a major challenge for chemists. Such studies are particularly relevant in oenology since they allow a better understanding of wine and spirit taste.

The use of glutathione (GSH) in winemaking has been legitimated recently, according to OIV resolutions OENO 445-2015 and OENO 446-2015 a maximum dose of 20 mg/L is now allowed to use in must and wine. Several studies have proven the benefits of GSH, predominantly in Sauvignon blanc. Thus, oxidative coloration of must and wine is limited, aroma compounds such as volatile thiols are preserved, and the development of ageing flavors such as sotolon and 2-aminoacetophenone is impeded. The protective effect may be explained by the high affinity of GSH to bind o-quinones which are formed during phenolic oxidation and which are known to initiate browning and other oxidative changes. Some researchers have proposed the hydroxycinnamic acid to GSH ratio (HGR) as an indicator of oxidation susceptibility of must and could show that lower ratios yielded lighter musts.

The presence of undesirable compounds in wines, such as ota, biogenic amines and pesticides residues, affects wine quality and can cause health problems for the consumer. Additionally, an excess of tannins can produce an undesirable increase in the astringency and bitterness of the wine, so tannins are also a target for reduction. The main tool that a winemaker has to reduce their content in the wine is fining. However, some of the fining agents commonly used in the winery can cause allergies or even increase the protein content in the wine, increasing the turbidity.

NIR spectroscopy has widely been tested in viticulture as powerful alternative to traditional analytical methods in the field of quality evaluation. NIR instruments have been used for assessing must and wine quality features in several works, but little information regarding their application on whole berries for polyphenol determination is available.