terclim by ICS banner
IVES 9 IVES Conference Series 9 INOCULATION OF THE SELECTED METSCHNIKOWIA PULCHERRIMA MP1 AS A BIOPROTECTIVE ALTERNATIVE TO SULFITES TO PREVENT BROWNING OF WHITE GRAPE MUST

INOCULATION OF THE SELECTED METSCHNIKOWIA PULCHERRIMA MP1 AS A BIOPROTECTIVE ALTERNATIVE TO SULFITES TO PREVENT BROWNING OF WHITE GRAPE MUST

Abstract

Enzymatic browning (BE) of must is caused by polyphenol oxidases (PPOs), tyrosinase and laccase. Both PPOs can oxidize diphenols such as hydroxycinnamic acids (HA) to quinones, which can later polymerize to form melanins [1], which are responsible of BE in white wines and of oxidasic haze in red wines. SO₂ is the main tool used to protect must from BE thanks to its capacity to inhibit PPOs [2]. However, the current trend in winemaking is to reduce and even eliminate this unfriendly additive. Among the different possible alternatives for protecting must against BE, the inoculation with a selected Metschnikowia pulcherrima MP1 is without any doubt one of the most promising ones.
For that purpose, white grapes were harvested, pressed and diluted 5 times with a model grape must synthetic buffer at pH = 3.50 and supplemented or not with 20 mg/L of SO₂, 2 UA/mL of laccase activity and 250 mg/L of the selected M. pulcherrima MP1 (Level2 Initia™, Lallemand Inc, Montreal, Canada). Immediately, the samples were saturated with O₂ and its concentration was noninvasively monitored overtime by luminescence (Nomasense TM O₂ Trace Oxygen Analyzer by Nomacorc S.A., Thimister Clermont, Belgium) [3]. Once oxygen consumption attained an asymptotic behavior the samples were used for color analysis [4] and for HPLC analysis of HA [5].
As expected, in the absence of SO₂, the must actively consumed O₂ and HA, and it turned intensely brown whereas in the presence of SO₂, the O₂ consumption rate (OCR) was significant lower, the HA concentra- tion was maintained at significant higher levels and the yellow color intensity remained at low values. In presence of laccase, OCR and browning intensity were even higher than in control conditions and the supplementation with SO₂ reduced both parameters but not as much as in the control must. Inoculation with the selected M. pulcherrima MP1 increased significantly OCR and protected the must from BE since the final yellow color was significantly lower and the HA concentration significantly higher than in control conditions although this protection was not so effective as that of SO₂. It seems the- refore that selected M. pulcherrima MP1 consumes O₂ very effectively making that some of the initially dissolved O₂ is not consumed by PPOs. In the presence of laccase, the supplementation with MP also protected the must from browning but not so efficiently.
This data confirms that the use of the selected M. pulcherrima MP 1 can be an interesting tool for redu- cing the dose of SO₂ without affecting seriously its final color quality.
Acknowledges: This research was funded by CICYT (project RTI 2018-095658-B-C33).

 

1. Oliveira CM, Silva-Ferreira AC, De Freitas V, Silva AM (2011) Food Res Int 44:1115-1126.
2. Ough, C.S., Crowell, E.A. (1987) J. Food Sci., 52, 386-389.
3. Pons-Mercadé P, Anguela S, Giménez P, Heras JM, Sieczkowski N, Rozès N, Canals JM, Zamora F (2021) Oeno One 2:147-158.
4. Ayala F, Echavarri JF, Negueruela AI (1997) Am J Enol Vitic 48:364-369.
5. Lago-Vanzela, E.S., Da-Silva, R., Gomes, E., García-Romero, E., Hermosín-Gutiérrez, I. (2011) J. Agric. Food Chem., 59, 8314−8323. 

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Article

Authors

Marco Bustamante¹, Pol Giménez¹, Arnau Just-Borras¹, Ignasi Solé-Clua¹, Jordi Gombau¹, José M. Heras², Nathalie Sieczkowski², Mariona Gil³, Joan Miquel Canals¹, Fernando Zamora1*

1. Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo 1, 43007 Tarragona, Spain
2. Lallemand Bio S.L. C/ Galileu 303. 1ª planta. 08028-Barcelona, Spain
3. Instituto de Ciencias Químicas Aplicadas. Facultad de Ingenieria. Universidad Autónoma de Chile. Sede Santiago, Campus Providencia. Av. Pedro de Valdivia 425, Providencia, Santiago. Chile

Contact the author*

Keywords

Metschnikowia pulcherrima, Browning, SO₂ alternative, Bioprotection

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

CHEMICAL DRIVERS OF POSITIVE REDUCTION IN NEW ZEALAND CHARDONNAY WINES

According to winemakers, wine experts and sommeliers, aromas of wet stone, mineral, struck match and flint in white wines styles, such as those produced from Vitis vinifera L. cv. Chardonnay, are considered to be hallmarks of positive reduction.1,2 In recent years, the production of Chardonnay styles defined by aroma characteristics related to positive reduction has become more desirable among wine experts and consumers. The chemical basis of positive reduction is thought to originate from the concentration of specific volatile sulfur compounds (VSCs), including methanethiol (MeSH) imparting mineral and chalk notes,3 and benzenemethanethiol (BMT) responsible for struck match and flint.1,4

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.

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.

EFFECTS OF INDUCED SUNBURN DAMAGES ON WHITE WINE PROPERTIES

Climate change is a great challenge for the environment and affects the wine industry as well. Sunburn damage of sensitive grapes increase with severe heat periods. Besides significant loss of yield sunburn, modifies sensory properties of the wines and may cause climate-related off-flavours. To initiate sunburn in a controlled way, in 2021 sunburn was directly induced in the vineyard with the GrapeBurner device, exposing grapes of the varieties Riesling and Pinot Blanc with UV and IR radiation. This device was first assembled by Kai Müller of the university in Geisenheim and consists of a carriage with 6 UV/IR lamps. A 15 min irradiation was applied in early September at 60°Oe. Due to the colder season in 2021 the grapes were not harmed by previous sunburn damage.

HOW TO EVALUATE THE QUALITY OF NATURAL WINES?

The movement of Natural wines has clearly increased in the last few years, to reach a high demand from consumers nowadays. Switzerland has not been left out of this movement and has created a dedicated association in 2021. This association has the ambition to develop a specific tasting sheet for natural wines. The study of the tasting notes shows that the olfactory description of wines is recent but predominant today. But wine is a product makes to be drunk and not (just) to smell it. Based on these findings, a new 100-point tasting sheet has been developed. The main characteristics are 1) an evaluation in the mouth before the description of the olfaction, 2) to give 50% of the points on the judgment for the mouth characteristics, 3) to pejorate the visual aspects only if the wine is judged as “not drinkable” and 4) to express personal emotions.