Monitoring of the Rioja red wine production process by 1 H-NMR spectroscopy.

BACKGROUND: As an inherently quantitative and unbiased analytical technique, proton nuclear magnetic resonance (1 H-NMR) provides an excellent method to monitor the quality of food and beverages, and a sensitive and informative tool to study the winemaking process. RESULTS: By using NMR, it is possible to monitor quantitative changes in wine metabolites (amino acids, organic acids and some phenolic compounds) during the winemaking process, including wine ageing. This study shows an increase in the concentration of the phenols at the beginning of alcoholic fermentation, as well as a stabilization and slight increase in gallic acid and a slight decrease in resveratrol during the oak barrel ageing step. CONCLUSION: This study demonstrates the potential of NMR as a process analytical technology (PAT) tool in the wine industry, by monitoring amino acids, organic acids and three polyphenols - gallic acid, catechin and resveratrol - during the winemaking process. This study of the time course evolution of wine has been conducted in a commercial winery rather than an experimental laboratory, demonstrating the capacity of this technique in commercial winemaking production. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

NMR study of histidine metabolism during alcoholic and malolactic fermentations of wine and their influence on histamine production.

The metabolic pathways of amino acids play a crucial role in the organoleptic and hygienic quality in wines. In particular, histidine is one of the most studied amino acids of wines due to histamine toxicity in humans, a biogenic amine derived from histidine by enzymatic decarboxylation. The development of new tools to increase knowledge on metabolism that produces histamine in wine is critical. This study investigated by using nuclear magnetic resonance (NMR) spectroscopy the transformation of histidine into histaminol and histamine during alcoholic and malolactic fermentations. The transformations of histidine into histaminol during alcoholic fermentation and into histamine during malolactic fermentation were observed. This paper highlights the importance of selecting lactic acid bacteria for malolactic fermentation to avoid the production of biogenic amines such as histamine.

Investigations of La Rioja terroir for wine production using 1H NMR metabolomics.

In this study, La Rioja wine terroir was investigated by the use of (1)H NMR metabolomics on must and wine samples. Rioja is a small wine region in central northern Spain which can geographically be divided into three subareas (Rioja Alta, Rioja Baja, and Rioja Alavesa). The winemaking process from must, through alcoholic and malolactic fermentation, was followed by NMR metabolomics and chemometrics of nine wineries in the Rioja subareas (terroirs). Application of interval extended canonical variate analysis (iECVA) showed discriminative power between wineries which are geographically very close. Isopentanol and isobutanol compounds were found to be key biomarkers for this differentiation.

Evidence of metabolic transformations of amino acids into higher alcohols through (13)C NMR studies of wine alcoholic fermentation.

Because the metabolite transformations in wine fermentation processes play a crucial role in the organoleptic and hygienic quality of wines, the nuclear magnetic resonance (NMR) technique is presented as a significant tool to follow metabolic pathways. In this paper, we investigated the transformation of several amino acids into their corresponding higher alcohols during the alcoholic fermentation, showing that the amino acids are totally consumed in the first stages of the process.

A thorough study on the use of quantitative 1H NMR in Rioja red wine fermentation processes.

In this study, we focused our attention on monitoring the levels of important metabolites of wine during the alcoholic and malolactic fermentation processes by quantitative nuclear magnetic resonance (qNMR). Therefore, using (1)H NMR, the method allows the simultaneous quantification of ethanol, acetic, malic, lactic, and succinic acids, and the amino acids proline and alanine, besides the ratio proline/arginine through fermentation of must of grapes corresponding to the Tempranillo variety. Each (1)H NMR spectrum gives direct and visual information concerning these metabolites, and the effectiveness of each process was assessed and compared by carrying out analyses using infrared spectroscopy to ethanol and acetic acid. The quantitative data were explained with the aid of chemometric algorithms.