Macrowine 2021
IVES 9 IVES Conference Series 9 Microbial stabilization of wines using innovative coiled UV-C reactor process: impact on chemical and organoleptic proprieties

Microbial stabilization of wines using innovative coiled UV-C reactor process: impact on chemical and organoleptic proprieties

Abstract

For several years, numerous studies aimed at limiting the use of SO2 in wines (thermal treatments, pulsed electric fields, microwaves …). Processes must be able to preserve the organoleptic qualities of wines with low energy consumption. In this context, ultraviolet radiations (UV-C), at 254 nm, are well known for their germicidal proprieties. In order to inactivate microorganisms in grape juice and wine without affecting the quality of the product, efficiency of UV-C treatment process should be optimized. Indeed, previous studies show a great efficiency for low absorbing liquids, but a poor one for high absorbing liquids, due to the lack of UV penetration. For this purpose, coiled tube UV-C reactor has been used in this study. The main component of this reactor is a FEP tube, helically wound around the UV lamp quartz sleeve. Dean vortices (radial flows) generated in this coiled tube reduce the UV dose (in J/L) required, ensuring a homogeneous dose distribution in absorbing liquids. UV-C dose was evaluated by actinometric measurments using iodide/iodate actinometry, allowing us to select the most suitable flow rate. The inactivation performance of this process on multiple strains (S.cerevisiae, D.bruxellensis diploid and triploid, and O.oeni) and the impact of UV-C treatment on sensorial, physicochemical proprieties and chemical compounds like thiols, were investigated on white and rosé wine. The entire continuous process has been evaluated in lab and semi-industrial scale at 2 hL/h. UV-C doses required to achieve a 6 log10 microbial reduction are low (less than 600J/L) in white and rosé wine. Sensorial and physicochemical analyses, after treatment and after three months, didn’t show differences between treated and untreated wines. Chemicals compounds quantification and sensorial analyses on red wine are currently in progress.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Rémy Junqua*, Cécile Thibon, Emmanuel Vinsonneau, Marta Avramova, Martine Mietton-Peuchot, Pons Alexandre, Remy Ghidossi

*ISVV

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Using elicitors in different grape varieties. Effect over their phenolic composition

Phenolic compounds are very important in crop plants and have been the subject of a large number of studies. Three main reasons can be cited for optimizing the level of phenolic compounds in crop plants: their physiological role in plants, their technological significance for food processing, and their nutritional characteristics1 Indeed, an enormous diversity of phenolic antioxidants is found in fruits and vegetables, and their presence and roles can be affected or modified by several pre- and postharvest cultural practices and/or food processing technologies (Ruiz-García et al. 2012, Goldman et al. 1999, Tudela et al. 2002). In winegrapes, the technological importance of phenolic compounds, mainly flavonoids, is well-known.

On the losses of dissolved CO2 from laser-etched champagne glasses under standard tasting conditions

Under standard champagne tasting conditions, the complex interplay between the level of dissolved CO2 found in champagne, its temperature, the glass shape, and the bubbling rate, definitely impacts champagne tasting by modifying the neuro-physico-chemical mechanisms responsible for aroma release and flavor perception. Based on theoretical principles combining heterogeneous bubble nucleation, ascending bubble dynamics and mass transfer equations, a global model is proposed (depending on various parameters of both the wine and the glass itself), which quantitatively provides the progressive losses of dissolved CO2 from laser-etched champagne glasses.

Identification of caffeic acid as a major component of Moscatel wine protein sediment

Proteins play a significant role in the colloidal stability and clarity of white wines [1]. However, under conditions of high temperatures during storage or transportation, the proteins themselves can self-aggregate into light-dispersing particles causing the so-called protein haze [2]. Formation of these unattractive precipitates in bottled wine is a common defect of commercial wines, making them unacceptable for sale [3]. Previous studies identified the presence of phenolic compounds in the natural precipitate of white wine [4], contributing to the hypothesis that these compounds could be involved in the mechanism of protein haze formation.

Foam characteristics of white, rosé and red sparkling wines elaborated by the champenoise method

Contribution Foam is the characteristic that differentiates sparkling wines from still wines, being the first sensory attribute that tasters and consumers perceive and that determines the final quality of sparkling wines [1]. The foaming properties mainly depend on the chemical composition of wines [2-3], and different factors involved in wine composition will have an effect on foam quality. In Spain, the sparkling wine market focuses on the production of white and rosé sparkling wine, with very low production of red sparkling wines. However, this type of wines is elaborated in countries like Australia, South-Africa, Argentina, Italy or Portugal, with a great acceptance by consumers. No studies on the foaming characteristics of red sparkling wines have been found.

Impact of some agronomic practices on grape skins anthocyanin content

Wine colour is the first quality characteristic to be assessed, especially regarding red wines. Anthocyanins are very well known to be the main responsible compounds for red wine colour. Red cultivars can synthesize and accumulate anthocyanins in berry skin to express their colour. However, anthocyanin accumulation is often influenced by a series of factors, such as genetic regulation, phytohormones, environmental conditions and viticultural management.