How the Management of pH during Winemaking Affects Acetaldehyde, Polymeric Pigments and Color Evolution of Red Wine

Angelita Gambuti,Francesco Errichiello,Luigi Moio,Antonio Guerriero,Martino Forino,Luigi Picariello

doi:10.3390/app12052555

Angelita Gambuti, Francesco Errichiello + Show 4 more

Open Access

https://doi.org/10.3390/app12052555

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Journal: Applied sciences	Publication Date: Feb 28, 2022
Citations: 5	License type: CC BY 4.0

Affiliation: University of Naples Federico II

Abstract

Due to climate change and the consequent rise in grape pH, there is often the necessity of acidifying musts or wines during winemaking. In this study, the effect of early (on musts, during fermentation) and late (on wines, after the end of the fermentation) acidification was evaluated. The experimental design consisted of the preparation of seven wines from the same batch of grapes fermented in a first tank at the original pH of 3.2 and two other tanks in which the pH was adjusted to 3.5 (3.5W) and 3.9 (3.9W). On the third day of fermentation, and one week after the end of the fermentation–maceration process, aliquots of both 3.5W and 3.9W were treated to lower pH to thus obtain four more wines. After one year of aging, wines treated so as to reach a 3.2 pH significantly differed from the control wine in terms of contents of acetaldehyde, tannins reactive towards proteins and polymeric pigments. Differences were more conspicuous when acidification was carried out after the end of the fermentation–maceration process. Data highlight that the timing of acidification has a significant effect on polymerization reactions typically occurring during wine aging.

Highlights

IntroductionWine production has been dramatically affected by climate changes
Over the past years, wine production has been dramatically affected by climate changes
To understand the impact of the timing and level of the acidification on red wine evolution, four samples treated with two levels of acid as musts

Summary

Introduction

Wine production has been dramatically affected by climate changes. The main effects detected in grape composition and production are the increase in sugar content, the earlier shift of the ripening period and the higher degradation of organic acids during the late stages of ripening [1]. The level of titratable acidity of musts, along with changes in other parameters such as the concentration of potassium cations and pH, directly affects the quality of wines because when the values of these parameters fall outside their optimal ranges, they have detrimental effects on the microbial and sensorial quality of the finished wines. Wines with high pH values are more susceptible to microbic contamination [2], and sulfur anhydride to avoid microbial and oxidative risks is required at higher concentrations [3]. Acidity is a primary driver of important management decisions related to contamination risks [4]. Acidity and pH are determinants for the sensorial properties of wines, a direct correlation between pH and sensory attributes is not possible because of several factors, including the human physiology that determines the sourness perception, the importance of the buffering power and the whole gustative equilibrium during the wine tasting [5,6]

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