 IVES 9 IVES Conference Series 9 Biosurfactant from corn-milling industry improves the release of phenolic compounds during red winemaking

Biosurfactant from corn-milling industry improves the release of phenolic compounds during red winemaking

Abstract

AIM: Biosurfactants can be used as emulsifier agents to improve the taste, flavour, and quality of food-products with minimal health hazards [1]. They are surface-active compounds with antioxidant and solubilizing properties [2]. In this study, a biosurfactant has been evaluated during red winemaking for its effect on fermentation dynamics, phenolic compounds extraction, and colour stabilization.

METHODS: The biosurfactant used was obtained from a fermented residual stream of corn-milling industry, named corn steep liquor (CSL). The harvested mass from Merlot winegrapes was distributed in 12 fermentation flaks with the same proportion of grape juice and solid parts. Six of them were added with CSL biosurfactant (1 g/L) whereas the other six were not added (control). Two fermentation protocols were assessed (spontaneous and Saccharomyces cerevisiae inoculated). Fermentation dynamics and kinetics, standard chemical parameters, colour characteristics, and phenolic composition were determined during maceration and at the end of malolactic fermentation.

RESULTS: During inoculated maceration, the biosurfactant-added samples showed significantly higher values of total polyphenols and colour intensity when compared to control, and lower ones of the three colour CIEL*a*b* coordinates (lightness, red/green, and yellow/blue). At the end of alcoholic fermentation, a higher percentage of more stable polymerized pigments was also observed. The final wine resulted to be richer in total polyphenols and anthocyanins, as well as in high molecular weight flavanols for the biosurfactant-added samples.

CONCLUSIONS

The biosurfactant addition did not affect negatively on inoculated fermentation dynamics and influenced positively the colour stability after malolactic fermentation resulting in darker and bluish wines. No significant changes on colour properties and related compounds were observed when spontaneous fermentation was performed.

ACKNOWLEDGMENTS

This study was supported by the Spanish Ministry of Economy and Competitiveness (MINECO project RTI2018-093610-B-100)

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Susana Río Segade

University of Torino, Italy,Susana RÍO SEGADE, University of Torino, Italy Vasileios ENGLEZOS, University of Torino, Italy Alejandro LÓPEZ-PRIETO, University of Vigo, Spain Maria Alessandra PAISSONI, University of Torino, Italy Simone GIACOSA, University of Torino, Italy Kalliopi RANTSIOU, University of Torino, Italy Luca ROLLE, University of Torino, Italy Benita PÉREZ CID, University of Vigo, Spain Ana Belén MOLDES, University of Vigo, Spain Jose Manuel CRUZ, University of Vigo, Spain

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Keywords

red grapes; winemaking; biosurfactant; fermentation dynamics; colour characteristics; phenolic compounds; polymeric pigments

Citation

LARGE-SCALE PHENOTYPIC SCREENING OF THE SPOILAGE YEAST BRETTANOMYCES BRUXELLENSIS: UNTANGLING PATTERNS OF ADAPTATION AND SELECTION, AND CONSEQUENCES FOR INNOVATIVE WINE TREATMENTS

Brettanomyces bruxellensis is considered as the main spoilage yeast in oenology. Its presence in red wine leads to off-flavour due to the production of volatile phenols such as 4-vinylphenol, 4-vinylguaiacol, 4-ethylphenol and 4-ethylguaiacol, whose aromatic notes are unpleasant (e.g. animal, leather, horse or pharmaceutical). Beside wine, B. bruxellensis is commonly isolated from beer, kombucha and bioethanol production, where its role can be described as negative or positive. Recent genomic studies unveiled the existence of various populations.

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Proposal for the development of a framework for a globally relevant wine sector climate change adaptation strategy

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Wine quality is defined by sensory and physico-chemical characteristics. In particular, sensory features are very important since they strongly condition wine acceptability by consumers. However, the evaluation of sensory quality can be subjective, unless performed by a tasting panel of experienced tasters. Therefore, it is of great relevance to establish relationships between objective chemical parameters and sensory perceptions, even though the complexity of wine composition makes it difficult. In this sense, more reliable relationships can be found for a particular wine typology or variety. The present study aimed to predict the perceived sensory quality from the physico-chemical parameters of ‘Barbera d’Asti’ DOCG red wines (Italy).

A mechanistic investigation of H/D scrambling processes in flavonoids

Several classes of flavonoids, such as anthocyanins, flavonols, flavanols and flavones, undergo a slow H/D exchange on aromatic ring A, leading to full deuteration at positions C(6) and C(8). Within the flavanol class, H-C(6) and H-C(8) of catechin and epicatechin are slowly exchanged in D2O to the corresponding deuterated analogues; even quercetin, a relevant flavonol representative, shows the same behaviour in a D2O/DMSOd6 1:1 solution. Detailed kinetic measurements of these H/D scrambling processes are here reported by exploiting the time-dependent changes of their peak areas in the 1H-NMR spectra taken at different temperatures. A unifying reaction mechanism is also proposed based on our detailed kinetic observations, even taking into account pH and solvent effects. Molecular modelling and QM calculations were also carried out to shed more light on several molecular details of the proposed mechanism.