terclim by ICS banner
IVES 9 IVES Conference Series 9 NEW TOOL FOR SIMULTANEOUS MEASUREMENT OF OXYGEN CONSUMPTION AND COLOUR MODIFICATIONS IN WINES

NEW TOOL FOR SIMULTANEOUS MEASUREMENT OF OXYGEN CONSUMPTION AND COLOUR MODIFICATIONS IN WINES

Abstract

Measuring the effect of oxygen consumption on the colour of wines as the level of dissolved oxygen decreases over time is very useful to know how much oxygen a wine is able to consume without significantly altering its colour. The changes produced in wine after being exposed to high oxygen concen-trations have been studied by different authors, but in all cases the wine has been analysed once the oxygen consumption process has been completed. This work presents the results obtained with the use of an equipment designed and made to measure simultaneously the level of dissolved oxygen and the spectrum of the wine, during the oxygen consumption process from saturation levels with air to very low levels, which indicate the total consumption of the dosed oxygen.

For this purpose, this equipment has been designed, built and prepared and has been validated with the measurement of red wines made from different grape varieties.

The equipment built has 2 mm quartz cuvettes for the measurement of the spectrum in the visible with a spectrophotometer and a sensor for the simultaneous measurement of dissolved oxygen with a luminescent measurement system, both measurements were carried out every 15 minutes during oxy-gen consumption. The tightness of the cuvettes during the process of measuring the kinetics of oxygen consumption was evaluated, as well as the reproducibility of the measurements of both parameters.

The results of this study show that the equipment designed and built is valid for monitoring the kinetics of oxygen consumption with the simultaneous measurement of the spectrum in the visible and dissolved oxygen. The tightness tests corroborated that all the cells used simultaneously are airtight, keeping their interior totally isolated from the exterior, showing a variability between cells of less than 10%. The results of the repeatability tests showed that the same wine measured simultaneously in the different cuvettes showed the same results both in the measurement of the consumption kinetics and in the measurement of the spectrum in the visible. The application of the system developed for the study of red wines allowed to know the characteristics of the consumption kinetics, obtaining that all red wines were initially able to take up the same amounts of oxygen (Omax), with values of 174 hPa. However, the wines made with Tempranillo grapes showed higher oxygen consumption (∆Omax_min), 115 hPa, and lower residual oxygen values (Omin), 59 hPa compared to than those made with the Garnacha grapes with 84 y 88 hPa of Omin and ∆Omax_min, respectively. One of the main advantages of this equipment is the ability to record the changes produced in the spectrum as the wine consumes oxygen, thus, an increase in red tones (450 and 580 nm) was observed in all the wines studied. It was found that the wines made with the Garnacha grapes underwent increases in absorbance between 400 and 460 nm and between 610 and 670 nm as they consumed oxygen, indicating an increase in the compounds responsible for the purple and yellow hues. On the other hand, wines made with the Tempranillo grapes, as they consumed oxygen, showed a decrease in purple hues.

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Poster

Authors

Marioli Alejandra, Carrasco-Quiroz ¹, Ignacio Nevares ², Ana Martinez-Gil ¹, Rubén Del Barrio-Galan ¹. Maria Asensio-Cuadrado ², Maria Del Alamo-Sanza ¹
1. Dpt. Química Analítica, UVaMOX-Group, Universidad de Valladolid, Avda. Madrid, 50, 34004 Palencia, Spain.
2. Dpt. Ingeniería Agrícola y Forestal, UVaMOX-Group, Universidad de Valladolid, Avda. Madrid, 50, 34004 Palencia, Spain

Contact the author*

Keywords

Oxygen consumption, colour, wine, kinetics

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

THE POTENTIAL USE OF SOLUBLE POLYSACCHARIDES TO PREVENT THE OXIDATION OF ROSÉ WINES

Lately, rosé wine is rapidly increasing its popularity worldwide. Short-time macerations with the red skin of the grapes cause the partial extraction of anthocyanins, which are responsible for the pinki-sh-salmon hue of rosé wines. However, the low quantity of tannins (antioxidants) and richness in phenolic acids, which can be easily oxidized into yellowish pigments, tend to predispose rosé wines to an undesirable browning. Although the use of SO₂ for the prevention of oxidation is highly extended, this practice is expected to be reduced. Therefore, the search for alternative oenological adjuvants that prevent the oxidation and browning of rosé wines is highly desired.

POTENTIAL OF PEPTIDASES FOR AVOIDING PROTEIN HAZES IN MUST AND WINE

Haze formation in wine during transportation and storage is an important issue for winemakers, since turbid wines are unacceptable for sale. Such haze often results from aggregation of unstable grape proteinaceous colloids. To date, foreseeably unstable wines need to be treated with bentonite to remove these, while excessive quantities, which are often required, affect the wine volume and quality (Cosme et al. 2020). One solution to avoid these drawbacks might be the use of peptidases. Marangon et al. (2012) reported that Aspergillopepsins I and II were able to hydrolyse the respective haze-relevant proteins in combination with a flash pasteurisation. In 2021, the OIV approved this enzymatic treatment for wine stabilisation (OIV-OENO 541A and 541B).

FUNCTIONALIZED MESOPOROUS SILICA IS A VIABLE ALTERNATIVE TO BENTONITE FOR WINE PROTEIN STABILIZATION

The presence of grape-derived heat unstable proteins can lead to haze formation in white wines [1], an instability prevented by removing these proteins by adding bentonite, a hydrated aluminum silicate that interacts electrostatically with wine proteins leading to their flocculation. Despite effective, using bentonite has several drawbacks as the costs associated with its use, the potential negative effects on wine quality, and its environmental impact, so that alternative solutions are needed.

IMPACT OF FINING WITH K-CARRAGEENAN, BENTONITE, AND CHITOSAN ON PROTEIN STABILITY AND MACROMOLECULAR COMPOUNDS OF ALBARIÑO WHITE WINE PRODUCED WITH AND WITHOUT PRE-FERMENTATIVE SKIN MACERATION

Pre-fermentative skin maceration is a technique used in white wine production to enhance varietal aroma, but it can increase protein concentration, leading to protein instability and haze formation [1]. To prevent protein instability, wine producers typically use fining agents such as bentonite, before wine bottling, which can negatively impact sensory characteristics and produce waste [2,3]. The aim of this study was to understand the impact of alternative techniques such as the application of polysaccharides (k-carrageenan and chitosan) on protein stability and on the wine macromolecular composition.

EFFECT OF MICRO-OXYGENATION IN COLOR OF WINES MADE WITH TOASTED VINE-SHOOTS

The use of toasted vine-shoots (SEGs) as an enological tool is a new practice that seeks to improve wines, differentiating them and encouraging sustainable wine production. The micro-oxygenation (MOX) technique is normally combined with alternative oak products with the aim to simulate the oxygen transmission rate that takes place during the traditional barrel aging. Such new use for SEGs implies a reduction in color due to the absorption by the wood of the responsible compounds, therefore, given the known effect that MOX has shown to have on the modification of wine color, its use together with the SEGs could result in an interesting implementation with the aim to obtain final wines with more stable color over time.