Macrowine 2021
IVES 9 IVES Conference Series 9 Effect of SO2, GSH and gallotannins on the shelf-life of a cortese white wine

Effect of SO2, GSH and gallotannins on the shelf-life of a cortese white wine

Abstract

AIM: Studying the effect of the addition of reduced glutathione (GSH) and/or gallotannins at bottling to limit the use of SO2 in white winemaking.

METHODS: Two aliquots of a Cortese white wine were oxygenated respectively to 5.5 ppm (experiment A) and 3 ppm (experiment B) of O2. The additives (SO2, gallotannins, GSH) were added at bottling at 2 levels following a full factorial plan: 20-60 mg/L of free SO2; absence/presence (40 mg/L) of tannins, absence/presence (20 mg/L) of GSH.

Experiment A was monitored during 12 months of storage (colour, polyphenolic composition, GSH, free and total SO2); the samples of experiment B were analyzed and the sensory profiles were defined 15 months after bottling. The oxygen consumption rate (OCR) was measured with a luminescence-based technology.

RESULTS: SO2 was the only additive that increased OCR and decreased colour intensity, without any effect on polyphenols content and HCTA. The presence of GSH limited the oxidative losses of SO2, mostly in the wines with higher SO2 levels. The effect of GSH decreased over time: after 8 months GSH was only present in traces. A higher SO2 content, though not statistically significant, was  still observed 12 months after bottling in the samples with both tannins and GSH. The sensory analyses distinguished the samples for the colour and some olfactory descriptors. The samples with GSH had more intense licorice notes and lower pinapple notes.

CONCLUSIONS

The oxidative browning of wines during bottle storage was limited only by the residual presence of free SO2: the colour intensity and the free SO2 content are inversely correlated. The addition of GSH, alone or together with tannins, reduced the losses of free SO2. The low efficacy of GSH could be due to the low dosage used.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Silvia Motta 

Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria – Centro di Ricerca Viticoltura ed Enologia, via P. Micca 35, 14100 Asti, Italy,Maria Carla Cravero*, Massimo Guaita*, Maria Rosa Lottero*, Antonella Bosso* *Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria – Centro di Ricerca Viticoltura ed Enologia, via P. Micca 35, 14100 Asti, Italy

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Keywords

oxygen, glutathione, tannins, SO2, white wine

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Grape berry size is a key factor in determining New Zealand Pinot noir wine composition

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Use of multispectral satellite for monitoring vine water status in mediterranean areas

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A large scale monitoring was organized in different vineyards in the Mediterranean region in 2021. 10 varieties amongst the most represented in this area were monitored (Cabernet sauvignon N, Chardonnay B, Cinsault N, Grenache N, Merlot N, Mourvèdre N, Sauvignon B, Syrah N, Vermentino B, Viognier B). The model was used to produce water status maps from Sentinel-2 images, starting from the beginning of June (fruit set) up to September (harvest). The average estimated SWP for each vine was compared to actual field SWP measures done by wine growers or technicians during usual monitoring of irrigation programs. The correlations between mean estimated SWP and mean measured SWP were at the same level than expected by the model. (Laroche Pinel, 2021) The general SWP kinetics were comparable. The estimated SWP would have led to same irrigation decisions concerning the date of first irrigation in comparison with measured SWP.

Acevedo-Opazo, C., Tisseyre, B., Ojeda, H., Ortega-Farias, S., Guillaume, S. (2008). Is it possible to assess the spatial variability of vine water status? OENO One, 42(4), 203.
Cohen, Y., Gogumalla, P., Bahat, I., Netzer, Y., Ben-Gal, A., Lenski, I., … Helman, D. (2019). Can time series of multispectral satellite images be used to estimate stem water potential in vineyards? In Precision agriculture ’19, The Netherlands: Wageningen Academic Publishers, pp. 445–451.
Laroche-Pinel, E., Duthoit, S., Albughdadi, M., Costard, A. D., Rousseau, J., Chéret, V., & Clenet, H. (2021). Towards vine water status monitoring on a large scale using sentinel-2 images. remote sensing, 13(9), 1837.
Laroche-Pinel,E. (2021). Suivi du statut hydrique de la vigne par télédétection hyper et multispectrale. Thèse INP Toulouse, France.
Scholander, P.F., Bradstreet, E.D., Hemmingsen, E.A., & Hammel, H.T. (1965). Sap pressure in vascular plants: Negative hydrostatic pressure can be measured in plants. Science, 148(3668), 339–346.

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Macrowine 2021
IVES 9 IVES Conference Series 9 Effect of SO2, GSH and gallotannins on the shelf-life of a cortese white wine

Effect of SO2, GSH and gallotannins on the shelf-life of a cortese white wine

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The development of new generations of multispectral satellites such as Sentinel-2 opens possibilities as to vine water status assessment (Cohen et al., 2019). Based on a three years field campaign, a model of Stem Water Potential (SWP) estimation on vine using four satellite bands in Red, Red-Edge, NIR and SWIR domains was developed (Laroche-Pinel et al., 2021). The model relies on SWP field measures done using a pressure chamber (Scholander et al., 1965), which is a common, robust and precise method to assess vine water status (Acevedo-Opazo et al., 2008). The model was mainly developed from from SWP measures on Syrah N (Laroche Pinel E., 2021).

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Acevedo-Opazo, C., Tisseyre, B., Ojeda, H., Ortega-Farias, S., Guillaume, S. (2008). Is it possible to assess the spatial variability of vine water status? OENO One, 42(4), 203.
Cohen, Y., Gogumalla, P., Bahat, I., Netzer, Y., Ben-Gal, A., Lenski, I., … Helman, D. (2019). Can time series of multispectral satellite images be used to estimate stem water potential in vineyards? In Precision agriculture ’19, The Netherlands: Wageningen Academic Publishers, pp. 445–451.
Laroche-Pinel, E., Duthoit, S., Albughdadi, M., Costard, A. D., Rousseau, J., Chéret, V., & Clenet, H. (2021). Towards vine water status monitoring on a large scale using sentinel-2 images. remote sensing, 13(9), 1837.
Laroche-Pinel,E. (2021). Suivi du statut hydrique de la vigne par télédétection hyper et multispectrale. Thèse INP Toulouse, France.
Scholander, P.F., Bradstreet, E.D., Hemmingsen, E.A., & Hammel, H.T. (1965). Sap pressure in vascular plants: Negative hydrostatic pressure can be measured in plants. Science, 148(3668), 339–346.

Better understand the soil wet bulb formation with subsurface or aerial drip irrigation in viticulture

The gradual change in rainfall patterns experienced in the south of France vineyards, especially around the Mediterranean sea, means that the vines are increasingly subject to summer drought. The winegrowers developped the use of irrigation techniques to ensure the maintenance of competitive yields in the production of wines under Protected Geographical Indication label. In practice, drip irrigation pipes can be installed above the ground or buried into the soil as well as at different distances from the vine row. The objective of this study was to examine the profiles of the wet bulbs of the soil obtained from two drip irrigation systems : aerial drip located under the vine row and subsurface drip placed in the middle of the inter-row. This experiment took place over two consecutive seasons (2020-2021) on a 3.4 ha Viognier plot in the Mediterranean region (PGI Oc, France) on sandy clay soil. The annual rainfalls were less than 400 mm. Soil water content probes were installed at different depths (20 – 40 – 60 – 80 cm) and at different lateralities from the vine row (30 – 60 – 90 – 120 cm) to control the formation of the soil wet bulb during irrigation. The mapping and the analysis of the data allowed a better understanding and differentiation of the water percolation when irrigating with subsurface or aerial drip. For the same amount of water and without differences of vine water status, it is shown that in a subsurface drip irrigation situation, the size of the wet bulb formed is larger than in aerial drip irrigation system.