Study of fungal and bacterial laccases for the reduction of ochratoxin A content in model wine

The last step in winemaking is packaging the wines for market placement, while preserving the quality attained during vinification. Since the 1980s, 2,4,6-trichloroanisole (TCA) has been recognised as an incidental and random contaminant of cork, with its migration into wine thought to contribute to ‘cork taint’. This molecule is not a cork component and little is known about how it is formed on trees. Its formation from the chlorine used to wash the cork stoppers, long suspected, has been excluded by the abandonment of chlorine washing.

Water status impact in viticulture has been widely explored, as it strongly affects grapevine physiology and grape chemical composition. It is considered as a key component of vitivinicultural terroir. Most of the studies concerning grapevine water status have focused on either physiological traits, or berry compounds, or traits involved in wine quality. Here, the response of grapevine to water availability during the ripening period is assessed through non-targeted metabolomics analysis of grape berries by ultra-high resolution mass spectrometry. The grapevine water status has been assessed during 2 consecutive years (2019 & 2020), through carbon isotope discrimination on juices from berries collected at maturity (21.5 brix approx.) for 2 Vitis vinifera cv. Pinot noir (PN) and Chardonnay (CH). A total of 220 grape juices were collected from 5 countries worldwide (Italy; Argentina; France; Germany; Portugal). Measured δ13C (‰) varied from -28.73 to -22.6 for PN, and from -28.79 to -21.67 for CH. These results also clearly revealed higher water stress for the 2020 vintage. The same grape juices have been analysed by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) and Liquid Chromatography coupled to Mass Spectrometry (LC-qTOF-MS), leading to the detection of up to 4500 CHONS containing elemental compositions, and thus likely tens of thousands of individual compounds, which include fatty acids, organic acids, peptides, phenolics, also with high levels of glycosylation. Multivariate statistical analysis revealed that up to 160 elemental compositions, covering the whole range of detected masses (100 –1000 m/z), were significantly correlated to the observed gradients of water status. Examples of chemical markers, which are representative of these complex fingerprints, include various derivatives of the known abscisic acid (ABA), such as phaesic acid or abscisic acid glucose ester, which are significantly correlated with higher water stress, regardless of the variety. Cultivar-specific behaviours could also be identified from these fingerprints. Our results provide an unprecedented representation of the metabolic diversity, which is involved in the water status regulation at the grape level, and which could contribute to a better knowledge of the grapevine mitigation strategy in a climate change context.

In viticulture sector to find new tools for pest management has become an urgent necessity. Hence, grapevines cultivation has high production rate demand and to meet the intensive market request, a massive use of pesticides is often required. In addition to the environmental problems associated with large use of chemicals, there is an increasing number of consumers which are asking for

The Spotted lanternfly (SLF), first detected in the U.S. in 2014, is an invasive phloem-feeding planthopper that poses a growing threat to grape and wine production in the U.S. In Pennsylvania, where it was first detected, reductions in grapevine production and fruit quality have been reported by commercial growers. Recent advances have begun to elucidate how SLF affects grapevine physiology and resource allocation, but no research has identified how SLF affects wine chemical composition and quality. Documented reductions in fruit sugar allocation due to heavy SLF phloem-feeding may have downstream effects on wine fermentation dynamics. Additionally, secondary metabolic responses stimulated by SLF may also influence berry chemical composition. The present study investigated SLF-mediated effects on wine composition through analysis of the volatile composition of wines produced from white- and red-fruited varieties of different Vitis parentage (e.g., Vitis vinifera vs. interspecific hybrids) following prolonged exposure to adult SLF phloem-feeding.

Acidity is often touted as a predictor of wine ageability, though surprisingly few studies have systematically investigated the chemical basis for this claim.