 IVES 9 IVES Conference Series 9 Inhibitory effect of sulfur dioxide, ascorbic acid and glutathione on browning caused by laccase activity

Inhibitory effect of sulfur dioxide, ascorbic acid and glutathione on browning caused by laccase activity

Abstract

AIM: The aim of this work was to study the inhibitory effect of the three most frequently used wine antioxidants – sulfur dioxide, ascorbic acid and glutathione – on the kinetics of browning caused by Botrytis cinerea laccase using a grape juice synthetic model in which (-)-epicatechin was the substrate.

METHODS: A grape juice model solution containing 100 g/L of D-glucose, 100 g/L of D-fructose and 4 g/l of tartaric acid adjusted to pH 3.5 was used for all the browning assays. (-)-Epicatechin was used as substrate at concentrations between 0 and 0.8 mM. This media was supplemented with sulfur dioxide at concentrations of 0, 10, 20 and 30 mg/L, ascorbic acid concentrations of 0, 50 and 100 mg/L, or reduced glutathione concentrations of 0, 20, 50 and 100 mg/L in order to determine how these antioxidants inhibit browning caused by laccase. Laccase from Botrytis cinerea was purified according to Vignault et al., (2019)1. Browning reaction was started by adding 2 units of laccase activity/ml and absorbance at 420 nm was measured at time 0, 15, 30 and 45 minutes. The slope of the regression straight line was determined in order to express the intensity of browning. The Michaëlis-Menten and Hill plots were depicted for each substrate in order to determine the kinetic parameters of browning: Vmax, K0.5 and Hill number. All the experiments were performed in triplicate.

RESULTS: All the three studied wine antioxidants, sulfur dioxide, ascorbic acid and glutathione reduced the laccase browning Vmax. Sulfur dioxide and glutathione also increased the K0.5, which indicates that sulfur dioxide not only decreases the Vmax of laccase browning but also the affinity for its substrate. In contrast, ascorbic acid did not change the values of K0.5, probably because it acts to reduce the availability of one of the laccase substrates (oxygen) and does not act directly on the enzyme.

CONCLUSIONS:

These results confirm that sulfur dioxide, ascorbic acid and glutathione really are effective in protecting grape juice against laccase browning. The effectiveness of ascorbic acid and glutathione also confirm that both antioxidants could be useful tools to reduce the doses of sulfur dioxide in winemaking, especially when grey rot is present. However, in the case of glutathione the dose needed to effectively protect grape juice against laccase browning is higher than the current maximum dose established by the OIV2. Given the safety of this compound, it would be advisable to increase its maximum dosage.

FUNDING:

This work was funded by CICYT (Efecto de las lacasas sobre la sensorialidad, calidad y salubridad de los vinos – project RTI2018-095658-B-C33).

ACKNOWLEDGMENTS:

Authors thank professors Marc Fermaud and Jean Roudet from INRAE, UMR SAVE, Bordeaux Science Agro, ISVV, France for having provided us with the B. cinerea strain.

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Joan Miquel Canals, Pol Giménez, Sergi Anguela, Arnau Just-Borras, Pere Pons-Mercadé, Jordi Gombau, Adeline Vignault, Joan Miquel Canals. Pierre-Louis Teissedre, Fernando Zamora

Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo, 1. 43007 Tarragona, Spain.,Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo, 1. 43007 Tarragona, Spain. Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo, 1. 43007 Tarragona, Spain. Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo, 1. 43007 Tarragona, Spain. Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo, 1. 43007 Tarragona, Spain. Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo, 1. 43007 Tarragona, Spain. Unité de Recherche Oenologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F33882 Villenave d’Ornon, France. – Laffort, 11 rue Aristide Bergès, 33270 Floirac, France. Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo, 1. 43007 Tarragona, Spain.Unité de Recherche Oenologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F33882 Villenave d’Ornon, France. Departament de Bioquímica i Biotecnologia, Facultat d’Enologia de Tarragona, Universitat Rovira i Virgili, C/Marcel.li Domingo, 1. 43007 Tarragona

Contact the author

Keywords

laccase, botrytis cinerea, browning, inhibition, sulfur dioxide, ascornic acid, glutathione

Citation

Influence of pedoclimatic factors during berry ripening in Burgundy

Berry composition at ripeness can be explained by many factors. This study was carried out from 2004 through 2011 in a 60 block network in the Yonne region, Burgundy.

ADDITION OF OAK WOOD ALTERNATIVE PRODUCTS: QUALITATIVE AND SENSORIAL EFFECTS FOR A WHITE WINE OF ALIGOTE

Wines matured in contact with wood are extremely popular with consumers all over the world. Oak wood allows the organoleptic characteristics of wine to be modified. Wines are enriched with volatile and non-volatile compounds extracted from the wood. The aromas extracted from oak wood contribute to the construction of the wine’s aromatic profile and the main polyphenols extracted can modify taste perceptions such as astringency and bitterness. All the compounds extracted from the wood thus contribute to the balance and quality of the wines.

Behaviour of two training systems for mechanical pruning combined with different nitrogen fertilizations on cv. Colombard

Today winegrowers involved in mechanical winter pruning are applying this viticultural technique on two main training systems, the free cordon, appearing to be the more efficient, and the trellised vertical shoot positioning (VSP) system. The main reasons for maintaining the trellis are generally due to common habits in vineyard management, risk of wind damage for the shoots, or risk of decrease in photosynthesis potential. The aim of the study was to assess the effects of the two training systems on vine. In addition, different nitrogen fertilization levels were applied on the two systems to evaluate the best combination to achieve yield and grape quality.

CHARACTERIZATION AND IDENTIFICATION OF YEAST BIOACTIVE PEPTIDES RELEASED DURING FERMENTATION AND AUTOLYSIS IN MODEL WINE

Aging wine on lees is a consolidated practice during which some yeast components (e.g., polysaccharides,
proteins, peptides) are released and solubilized in wine thus, affecting its stability and quality.
Apart from the widely studied mannoproteins, the role of other yeast components in modulating wine
characteristics is still scarce. Wine peptides have been studied for their contribution to taste, antioxidant,
and antihypertensive potentials. However, the peptides detected in wine can be influenced by the
interaction between yeasts and grape components.

De novo Vitis champinii whole genome assembly allows rootstock-specific identification of potential candidate genes for drought and salt tolerance

Vitis champinii cultivars Ramsey and Dog-ridge are main choices for rootstocks to adapt viticulture in semi-arid and arid regions thanks to their distinctive tolerance to drought and salinity. However, genetic studies on non-vinifera rootstocks have heavily relied on the grapevine (Vitis vinifera) reference genome, which difficulted the assessment of the genetic variation between rootstock species and grapevines. In the present study, this limitation is addressed by introducing a novo phased genome assembly and annotation of Vitis champinii. This new Vitis champinii genome was employed as reference for mapping RNA-seq reads from the same species under drought and salt stresses, and for comparison the same reads were also mapped to the Vitis vinifera PN40024.V4 reference genome. A significant increase in alignment rate was gained when mapping Vitis champinii RNA-seq reads to its own genome, compared to the Vitis vinifera PN40024.V4 reference genome, thus revealing the expression levels of genes specific to Vitis champinii. Moreover, differences in coding sequences were observed in ortholog genes between Vitis champinii and Vitis vinifera, which therefore challenges previous differential expression analyses performed between contrasting Vitis genotypes on the same gene from the Vitis vinifera genome. Genes with possible implications in drought and salt tolerance have been identified across the genome of Vitis champinii, and the same genomic data can potentially guide the discovery of candidate genes specific from Vitis champinii for other traits of interest, therefore becoming a valuable resource for rootstock breeding designs, specially towards increased drought and salinity due to climate change.