OENO IVAS 2019 banner
IVES 9 IVES Conference Series 9 OENO IVAS 9 OENO IVAS 2019 9 Analysis and composition of grapes, wines, wine spirits 9 The fundamental role of pH in the anthocyanins chemical behavior and in their extractability during winemaking

The fundamental role of pH in the anthocyanins chemical behavior and in their extractability during winemaking

Abstract

The chemical behavior of anthocyanins is considerably affected even by slight pH variations with impor-tant implications for the winemaking as well as for the wine conservation. Considering that this is a cen-tral issue to the enological sector, we decided to better investigate the influence of pH on the anthocyanin chemistry.

Initially, by chromatographic and advanced NMR techniques the chemical behavior of malvi-din- 3-O-glucoside was studied in wine-like solutions with pH values ranging from 3 to 4. First, the already composite aqueous equilibrium of malvidin-3-O-glucoside turned out to be even more complex than so far thought, as a new hydration product of the anthocyanin was detected and characterized in solution.

More importantly on account of its technological implications, the anthocyanin solubility appeared to decrease remarkably as the pH value of the wine-like solutions increased. A dramatic drop in terms of anthocyanin solubility was observed at pH 3.32, where the measured molecule concentration was reduced to almost 25% the expected one. Also, at such pH level the anthocyanin self-association appeared significantly affected.

In more detail,the flavylium ion self-association predominant at lower pH levels was altered and found to co-occur with a preferential co-pigmentation involving flavylium ion species and the trans-chalcone form of malvidin-3-O-glucoside. At higher pH values, this latter association was the only one detected in so-lution. In the light of these results, we set up an experimental protocol with the purpose of analyzing the pH influence on the anthocyanin chemistry and extractability in real wines produced by varying their pH levels during the maceration-fermentation phases.

Preliminary chemical analysis of such wines provided data consistent with those obtained in wine-like solutions. Indeed, the extraction of malvidin-3-O-gluco-side and that of anthocyanins in general was more contained as the pH value increased.

Additionally, other molecules of enological interest, including catechins, cinnamates, syringic acid and terpenoids, turned out to be affected by the wine pH. These analytical data highlight the fundamental role of pH during the wine-making and the importance of regulating its level to obtain wines with the desired polyphenolic structure.

Boulton. American journal of enology and viticulture, 52(2), 67-87 (2001). Forino, M., Gambuti, A., Luciano, P., Moio, L. J. Agric. Food Chem. (2019) doi:10.1021/acs.jafc.8b05895 

DOI:

Publication date: June 11, 2020

Issue: OENO IVAS 2019

Type: Article

Authors

Martino Forino, Angelita Gambuti, Luigi Picariello, Luigi Moio

Department of Agricultural Sciences, University of Napoli “Federico II”−Oenology Sciences Section Viale Italia, 83100 Avellino, Italy

Contact the author

Keywords

Anthocyanin , pH, pigmentation, anthocyanin solubility

Tags

IVES Conference Series | OENO IVAS 2019

Citation

Related articles…

Pruned vine biomass exclusion from a clay loam vineyard soil – examining the impact on physical/chemical properties

The wine industry worldwide faces increasing challenges to achieve sustainable levels of carbon emission mitigation. This project seeks to establish the feasibility of harvesting winter pruned vineyard biomass (PVB) for potential use in carbon footprint reduction, through its use as a renewable biofuel for energy production. In order to make this recommendation, technical issues such as the potential environmental impact, chemical composition and fuel suitability, and logistical challenges of harvesting biomass needs to be understood to compare with the results from similar studies. Of particular interest is the role PVB plays as a carbon source in vineyard soils and what effect annual removal might have on soil carbon sequestration. A preliminary trial was established in the Waite Campus vineyard (University of Adelaide) to test current management strategies. Vines are grown in a Eutrophic, Red Dermosol clay loam soil with well managed midrow swards. A comparison was undertaken of mid-row treatments in two 0.25 Ha blocks (Shiraz and Semillon), including annual cultivation for seed bed preparation, the deliberate exclusion of PVB (25 years) and incorporation of PVB (13 years) at an average of 3.4 and 5.5 Mg/Ha-1 for Shiraz and Semillon respectively. In both 0-10cm and 10-30cm soil core sample depths, combined soil carbon % measures in the desired range of 1.80 to 3.50, were not significantly different between treatments or cultivars and yielded an estimated 42 Mg/ha-1 of sequestered soil carbon. Other key physical and chemical measures were likewise not significantly different between treatments. Preliminary results suggest that in a temperate zone vineyard, managed such as the one used in this study, there is no long term negative impact on soil carbon sequestration through removing PVB. This implies that growers could confidently harvest PVB for use in several end fates including as a bio fuel.

Environmental sustainability in the production of grappa with the use of mould-resistant grape varieties: the aroma characterisation of distillates

Grappa is the most important italian spirit and its production includes elements of history, tradition, and culture of the transalpine country. In accordance with EU laws, grappa is obtained from the fermentation and distillation of the pomace, eventually added with fermentation lees and water. Grappa is one of the richest fruit distillates in volatile compounds that confer to the product its characteristic flagrance. The aroma is largely due to the volatile compounds present in the raw materials, in particular alcohols, esters and carbonyl compounds formed during the alcoholic fermentation, but also to grape aromas such as terpenols and norisoprenoids, that confers grappa the distinctive floral scents.

Il piano regolatore delle città’ del vino: aspetti urbanistici, economici e turistici

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" text_orientation="center" custom_margin="65px||18px||false|false"...

Impact of defoliation on leaf and berry compounds of Vitis vinifera L. Cv. Riesling investigated using non-destructive methods)

Climate change has a strong impact on the earlier onset of important phenological stages and plant development in viticulture.

INFLUENCE OF CHITOSAN, ABSCISIC ACID AND BENZOTHIADIAZOLE TREATMENTS ON SAVVATIANO (VITIS VINIFERA L.) WINES VOLATILE COMPOSITION PROFILE

In the last decades the use of bioestimulants in viticulture have been promoted as alternative to conven- tional pesticides. Moreover, as bioestimulants promote the biosynthesis of secondary metabolites in grape berries, several studies had investigated their influence on the accumulation of phenolic com- pounds (Monteiro et al., 2022). However, few studies, so far, are focused on the accumulation of the vo- latile compounds and their impact on the produced wines (Giménez-Bañón et al., 2022; Gomez- Plaza et al., 2012; Ruiz Garcia et al., 2014).
This study was conducted in a single vineyard of white autochthonous grapevine variety Savvatia- no (Vitis vinifera L.) in Muses Valley (Askri, Viotia, Greece). Chitosan (CHT), Abscisic Acid (ABA) and Benzothiadiazole (BTH) were applied.