NEAR INFRARED SPECTROSCOPY FOR THE ESTIMATION OF TEMPRANILLO BLANCO VOLATILE COMPOSITION ALONG GRAPE MATURATION

Since the use of sodium arsenite was banned in 2001, Grapevine Trunk Diseases (GTDs) have become even more widespread increasing (1).To avoid pathogen entry, pruning, an age-old practice, is increa- singly coming to the fore. As the vine is a liana (2), any excessive woody proliferation has to be stopped. This can preserve grapevine life, provided it does not damage the diaphragm.

Color is one of the key elements for the marketing of rosé wines due to their packaging in transparent bottles. Their broad color range is due to the presence of pigments belonging to phenolic compounds extracted from grapes or formed during the wine-making process. However, the mechanisms responsible for such diversity are poorly understood. The few investigations performed on rosé wines showed that their phenolic composition is highly variable, close to that of red wines for the darkest rosés but very different for light ones [1]. Moreover, large variations in the extent of color loss taking place during fermentation have been reported but the mechanisms involved and causes of such variability are unknown.

The interest in indigenous non-Saccharomyces yeast for use in wine production has increased in recent years because they contribute to the complex character of the wine. The aim of this work was to investigate the fermentation products of ten indigenous strains selected from a collection of native yeasts established at the Institute for Adriatic Crops and Karst Reclamation in 2021, previously isolated from Croatian Maraština grapes, belonging to Hypopichia pseudoburtonii, Metschnikowia pulcherrima, Metschnikowia sinensis, Metschnikowia chrysoperlae, Lachancea thermotolerans, Pichia kluyveri, Hanseniaspora uvarum, Hanseniaspora guillermondii, Hanseniaspora pseudoguillermondii, and Starmerella apicola species, and compare it with commercial non-Saccharomyces and Saccharomyces strains.

Grape pomace is one of the main by-products generated after pressing in winemaking.Emerging methods, such as ultrasound-assisted extraction with eutectic mixtures, have great potential due to their low toxicity, and high biodegradability. Choline chloride (ChCl) was used as a hydrogen bond acceptor and its corresponding hydrogen bond donor (malic acid, citric acid, and glycerol: urea). Components were heated at 80 °C and stirred until a clear liquid was obtained. Distilled water was added (30 % v/v). A solid-liquid ratio of 1 g pomace per 10 ml of eutectic solvent was used.

Laccases from lactic acid bacteria (LAB) are described as multicopper oxidase enzymes with copper union sites. Among their applications, phenolic compounds’ oxidation and biogenic amines’ degradation, have been described. Besides, the role of LAB in the toxicity reduction of ochratoxin A (OTA) has been reported (Fuchs et al., 2008; Luz et al., 2018). Fungal laccases, but not bacterial laccases, have been screened for OTA and mycotoxins’ degradation (Loi et al., 2018). OTA is a mycotoxin produced by some fungal species, such as Penicillium and Aspergillus sp., which infect grape bunches used for winemaking.