 IVES 9 IVES Conference Series 9 Influence of must fining on wine pinking: relationship between electrochemical and colorimetric measurements and pinking attitude of wine

Influence of must fining on wine pinking: relationship between electrochemical and colorimetric measurements and pinking attitude of wine

Abstract

AIM: “Pinking” is a term used to define an abnormal pink coloration assumed by white wines in certain cases. Despite the are many hypotheses about the causes of this phenomenon, pinking still represents an issue for the wine industry. In the absence of reliable preventive strategies, wineries often rely on treatments such as charcoal fining, which is also negatively impacting wine aroma. This study aims at evaluating the potential of different fining agents based on animal or vegetal proteins to prevent wine pinking when applied at the level of must clarification. The work was carried out on Lugana wines, which is well-recognised as sensible to pinking problems.

METHODS: Two experimental Lugana musts were obtained by applying a standard winemaking protocol and were then clarified with different commercial preparations based on vegetal proteins or casein, alone or in combination with PVPP. A control only using pectolytic enzyme was also prepared. Finings were carried out at 4°C for 16h, and the clear must (200 NTU) was then fermented in controlled conditions. At the end of fermentation all wines were bottled with 25 mg/L of free SO2. Musts and wines were submitted to linear sweep voltammetry, colorimetric (CIELab) and spectrophotometric analyses. Pinking was assessed by CIELab.

RESULTS: Must fining with products based on combination of vegetable proteins and PVPP allowed significant reduction of must content in oxidizable compounds assessed by voltammetry, and this difference was still detected in the finished wines. After one month of bottle aging (free SO2 being 20 mg/L in all wines) pinking was detected for all wines except for those obtained from musts treated with potato or pea protein combined with PVPP. Voltammetric features of the must were shown to be well correlated with the risk of wine pinking. Analysis after one year of bottle aging confirmed the potential of fining to prevent pinking.

CONCLUSIONS: The type of fining agent used in must fining affects the occurrence of pinking in the finished wines. Vegetable proteins in combination with PVPP showed high potential for pinking prevention. Voltammetric analyses could be a promising tool for rapid assessment of the efficacy of fining treatments towards pinking.

ACKNOWLEDGMENTS:

The present work was financially supported by Biolaffort.

DOI:

Publication date: September 28, 2021

Issue: Macrowine 2021

Type: Article

Authors

Maurizio Ugliano 1, Riccardo MANARA 1, Eduardo VELA ROMAN 1, Virginie MOINE 1, Arnaud MASSOT 2, Davide SLAGHENAUFI 2.

1 University of Verona, Italy.
2 Biolaffort, France.

Contact the author

Keywords

pinking, fining, vegetable proteins, linear sweep voltammetry

Citation

Recognition of terroir in american viticultural areas

Un’ Area di Viticultura Americana, detta AVA, è una regione vinicola delimitata ed è distinguibile da caratteristiche geografiche i cui confini sono stati definiti da regolamenti. Il sistema AVA rappresenta un ‘accettazione del concetto di terroir (terreno), come dimostrano gli studi che confermano il carattere regionale dei vini AVA e dalla sviluppo di subdenominazioni più relazionate al terreno.

Phenological stage dependency of Cabernet Sauvignon and Grenache response to water and nutrient limitation

As the frequency and intensity of drought events increase, understanding the mechanisms of plant resilience to water deficit is crucial. To maintain an appropriate plant yield, a common practice is the application of high amounts of fertilizers with negative environmental impacts. The single and combined effect of water deficit and nutrient availability, namely nitrogen (N) and potassium (K), in Vitis Vinifera L. cv. Cabernet Sauvignon and Grenache was evaluated. Two-year-old grapevine plants grafted on SO4 rootstock were transferred in pots under semi-environmental conditions. During the growing season, plants were either maintained well-watered (100% ETc) or subjected to a controlled water deficit irrigation (33% ETc).

Callinikos: the new white table grapeseedless variety for biological produce

This paper presents is the create, the study and amplographic description the new seedless grape variety «Callinicos» was created by P. Zamanidis at the Athens Vine Department

Recovery and purification of proteins from grape seed byproducts using proteomic and separative techniques

Grape seeds account for around 5% of the weight of the whole grape berry, representing approximately 40%-50% of the solid by-products that the different wine industries generate during the winemaking process.

Impact of yeast strain and aging time on the secondary metabolites, macromolecule composition, and sensory attributes of sparkling wines elaborated by the traditional method

The occurrence of aroma and macromolecule constituents in sparkling wines, directly influencing their organoleptic characteristics, is affected by several factors, including the grape cultivar, base-wine particularities, inoculated yeasts, the aging time, and winemaking practices [1].