Macrowine 2021
IVES 9 IVES Conference Series 9 How the management of ph during winemaking affects acetaldehyde evolution and the formation of polymeric phenolics over the red wine aging

How the management of ph during winemaking affects acetaldehyde evolution and the formation of polymeric phenolics over the red wine aging

Abstract

AIM: The aim of this study is to evaluate the role of pH on both the acetaldehyde chemistry and wine phenolics evolution over the aging period. In addition, the effect of both an early (on musts) and late (on wines soon after the end of the fermentation) acidification was evaluated.

METHODS: The experimental design consisted in the preparation of 7 wines from the same batch of grapes fermented in a first tank at the original pH of 3.2 (3.2W) 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 some aliquots of both 3.5W and 3.9W were treated to reach a 3.2 pH to afford four more wines. Polymeric pigments and phenolics were evaluated by spectrophotometry, MS and NMR techniques, acetaldehyde and anthocyanins by HPLC-DAD and reactivity of tannins towards saliva by electrophoresis. Wines were analyzed soon after the end of the fermentation and after one-year aging.

RESULTS: By increasing the pH level from 3.2 to 3.9, the amount of low polymerized flavans, individual anthocyanins and tannins reactive to BSA and saliva decreased. Conversely, an increase of acetaldehyde, of pigments resistant to the bleaching, and of ethylene-linked polymeric pigments was detected. After one year of aging, wines treated to reach a 3.2 pH significantly differ from 3.2W in acetaldehyde, tannins reactive towards proteins and polymeric pigments. This behavior was more evident when the acidification was carried out soon after the end of the fermentation-maceration process.

CONCLUSIONS

High pH values favor the polymerization of phenolics over the wine aging and results suggested that the effect is predominant when pH was increased during the fermentation, hence successive pH modulations have little (if any) effect on some typical reactions occurring during wine aging.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Angelita Gambuti

Department of Agricultural Sciences, University of Napoli “Federico II”- Enology Sciences Section, Viale Italia, 83100, Avellino, Italy, Luigi PICARIELLO, Department of Agricultural Sciences, University of Napoli “Federico II”- Enology Sciences Section, Viale Italia, 83100, Avellino, Italy. Martino  FORINO, Department of Agricultural Sciences, University of Napoli “Federico II”- Enology Sciences Section, Viale Italia, 83100, Avellino, Italy Alessandra RINALDI, Department of Agricultural Sciences, University of Napoli “Federico II”- Enology Sciences Section, Viale Italia, 83100, Avellino, Italy. Biolaffort, 126 Quai de la Souys, 33100 Bordeaux, France. Luigi MOIO, Department of Agricultural Sciences, University of Napoli “Federico II”- Enology Sciences Section, Viale Italia, 83100, Avellino, Italy.

Contact the author

Keywords

red wine, aging, ph, polyphenols

Citation

Related articles…

The impacts of frozen material-other-than-grapes (MOG) on aroma compounds of red wine varieties

An undesirable note called “floral taint” has been observed in red wines by winemakers in the Niagara region caused by large volumes of frozen leaves and petioles [materials-other-than-grapes (MOG)] introduced during mechanical harvest and subsequent winemaking late in the season. The volatiles, which we hypothesized are responsible, are primarily terpenes, norisoprenoids, and specific esters in frozen leaves and petioles. The purpose of this study was to investigate the volatile compounds which may cause the floral taint problem and explore how much of them (thresholds) may lead to the problem. Also, the glycosidic precursors of some of these compounds were analyzed to see the changes happening during frost events.

Aromatic profile of six different clones of Chardonnay grape berries in Minas Gerais (Brazil)

Aromas are one of the key points in food analysis since they are related to character, quality and consequently consumer acceptance. It is not different in the winery industry, where the aromatic profile is a combination of viticultural and oenological practices. Based on the development of more aromatic clones and on the potential to produce sparkling wines at Caldas, in the southern region of Minas Gerais (Brazil) (21°55´S and 46°23´W, altitude 1,100m), the aim of this work was the determination of volatile compounds in six different clones of Chardonnay grape berries to better understand which compounds add bouquet to the wine, and additionally comprehend the impacts of the edaphoclimatic and annual conditions on the improvement of grape-growing and winemaking practices.

Improving stilbenes in vitis Labrusca L. Grapes through methyl jasmonate applications

Grapes (Vitis sp.) are considered a major source of phenolic compounds such as flavonols, anthocyanins and stilbenes. Studies related to the beneficial effects of these compounds on health have encouraged research aimed at increasing their concentration in fruits. On this behalf, several plant growth regulators such as jasmonic acid and its volatile ester, methyl-jasmonate (MeJa), have demonstrated promising results in many fruits. However, Brazilian subtropical climate might interfere on treatment response. The present study aims to evaluate the application of MeJa in the pre-harvest period in Concord and Isabel Precoce grapes (Vitis labrusca L.).

Service crop effects on grapevine water and nitrogen status and yield under Mediterranean climate

Service crops in vineyard can provide multiple ecosystem services but they can also lead to competition with the grapevine for soil resources in the Mediterranean region due to potential severe droughts (Garcia et al., 2018). One of the levers of action to manage this competition is the choice of species adapted in terms of growth dynamics and water and nutrients’ needs. The objectives of this study were to determine the effect of temporary service crops on grapevine water and nitrogen status and grapevine yield and yield components in a Mediterranean vineyard.

Impact of deficit irrigation strategies on terpene concentration in Gewürztraminer grapes

Deficit irrigation is a viticultural practice often applied to improve the phenolic composition of red grapes and wines. However, the impact of this practice on grape terpenes – key aromatics for several grapes and wines – remains largely unknown. This study investigated the impact of deficit irrigation strategies on free and glycosylated terpenes in Gewürztraminer grapes. In a field study conducted in Oliver, BC, in 2016, 2017, and 2018, deficit irrigation regimes were applied to Gewürztraminer vines at different developmental stages (pre-veraison = Early Deficit, ED; post-veraison = Late Deficit, LD; throughout the season = Prolonged Deficit, PD). A well-irrigated control (CN) treatment was also established.