Luís Filipe-Ribeiro

Comparison between different types of carboxylmethylcellulose and other oenological additives used for white wine tartaric stabilization

Carboxylmethylcellulose (CMC) is authorised to prevent wine tartaric instability. The effect of CMC structural characteristics on their effectiveness is not well understood. The main purpose of this study was to compare the impact of CMCs with different degrees of substitution and molecular weight, on tartaric stability, tartaric acid, mineral concentration, phenolic compounds, chromatic and sensory characteristics in white wines, and compare its effectiveness with other oenological additives. Mini-contact test showed that all CMCs and metatartaric acid stabilized the wines; however, some arabic gums and mannoproteins do not stabilized the wines. CMCs had no significant effect on tartaric acid, potassium, calcium and sensory attributes. Tartaric stabilization effectiveness depends on CMCs degree of substitution, but also on wine matrix, probably its initial potassium content. Results suggest that CMC is a good alternative to white wine tartaric stabilization; nevertheless deeper structure knowledge is necessary in order to choose the appropriate CMC for a given tartaric instability.

A simple, cheap and reliable method for control of 4-ethylphenol and 4-ethylguaiacol in red wines. Screening of fining agents for reducing volatile phenols levels in red wines.

Brettanomyces/Dekkera produces 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) from hydroxycinnamic acids that affect the wine aroma and overall quality. A simple, cheap, fast and reliable quantitation method is needed for routine quality control of wines. In this work a simple method based on one simple liquid-liquid extraction with pentane/diethyl ether (2:1) and analysis by GC-MS allow to obtain very good recoveries (98-102%) and low quantification limits (24 and 11μg/L for 4-EP and 4-EG, respectively), well below the sensory threshold for these volatile phenols and with an adequate measurement uncertainty: 70, 1.75 and 78, 1.95 and 1.35μg/L for levels of 1000, 25μg/L for 4-EP and 1000, 25 and 10μg/L for 4-EG, respectively. In addition a screening of eight fining agents (mineral, protein and polysaccharide based) for reducing the levels of these volatile phenols in red wines was performed, and the impact on the physicochemical characteristics of red wines was evaluated. At the levels used, activated carbon was the most efficient fining agent in removing 4-ethylphenol and 4-ethylguaiacol from red wines (57%) resulting in a 75% decrease of headspace concentration of these volatile phenols. Lower reductions were observed when using egg albumin (19%) resulting in a 30% decrease in the headspace concentration. Other fining agents although not reducing the total amount of the volatile phenols present in wine decreased their concentrations in the headspace like isinglass (27%), carboxymethylcellulose (15%) and chitosan (27%). All of these fining agents could be a possibility for treating wine contaminated with 4-ethylphenol and 4-ethylguaiacol.

Influence of the structural features of commercial mannoproteins in white wine protein stabilization and chemical and sensory properties

The cloudy aspect formed in white wines due to protein instability is a visual defect. Sodium bentonite is the most commonly used fining agent to treat this instability, but has usually a negative impact on the wines physicochemical and sensory characteristics. Aiming to find suitable alternatives, eleven commercial mannoproteins were chemically characterized concerning their sugar composition and protein content, and their effectiveness on wine protein stabilization. Also, their effect on the amount and nature of phenolic compounds, browning potential, chromatic and sensory characteristic was evaluated. Protein stabilization effectiveness was related to their chemical composition, namely their high mannose to glucose ratio. Additionally, some mannoproteins decreased the browning potential. Thus, mannoproteins could be an effective alternative for protein stabilization, preserving or even improving wine quality.

Reduction of 4-ethylphenol and 4-ethylguaiacol in red wine by activated carbons with different physicochemical characteristics: Impact on wine quality

Activated carbon (AC) could be a solution to remove 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) off-flavours from Dekkera/Brettanomyces contaminated red wines. The relation between AC physicochemical characteristics and removal efficiency of these compounds is unknown. The impact of ACs characteristics on 4-EP and 4-EG removal, phenolic and headspace aroma composition was studied. All ACs reduced significantly 4-EP and 4-EG levels (maximum 73%). Their efficiency was related to their surface area and micropores volume. A higher surface area of mesopores and total pore volume were detrimental for anthocyanins and colour intensity, while a higher surface area and micropores volume were important for removing phenolic acids. Volatile phenols reduction was more important for the positive fruity attribute perception than the abundance of headspace aroma compounds. With an optimal selection of the AC physicochemical characteristics it was possible to remove efficiently the volatile phenols without impacting negatively on the wine sensory quality.

Data on changes in red wine phenolic compounds, headspace aroma compounds and sensory profile after treatment of red wines with activated carbons with different physicochemical characteristics

Data in this article presents the changes on phenolic compounds, headspace aroma composition and sensory profile of a red wine spiked with 4-ethylphenol and 4-ethylguaiacol and treated with seven activated carbons with different physicochemical characteristics, namely surface area, micropore volume and mesopore volume (“Reduction of 4-ethylphenol and 4-ethylguaiacol in red wine by activated carbons with different physicochemical characteristics: impact on wine quality” Filipe-Ribeiro et al. (2017) [1]). Data on the physicochemical characteristics of the activated carbons are shown. Statistical data on the sensory expert panel consistency by General Procrustes Analysis is shown. Statistical data is also shown, which correlates the changes in chemical composition of red wines with the physicochemical characteristics of activated carbons used.

A simple dispersive solid phase extraction clean-up/concentration method for selective and sensitive quantification of biogenic amines in wines using benzoyl chloride derivatisation

A simple, quick, cheap and green dispersive solid phase extraction (dSPE) method followed by benzoyl chloride pre-column derivatisation for HPLC-UV determination of twelve biogenic amines (BAs) in wines is proposed for the first time. The dSPE using a strong cation exchange resin increased the selectivity and sensitivity of the analysis by elimination of interfering compounds and a five-fold enrichment of BAs. The method presented an adequate precision and linearity with detection limits ranging from 0.133 to 0.509 mg/L. Recoveries ranging from 72 to 99% prove the accuracy of the method for determining BAs in red, white and Tawny Port wine samples yielding chromatograms clean from interferents. The method was applied successfully to the analysis of 31 young red wines from different Portuguese wine regions. The dSPE method although has a potential of broader application to other food matrixes, other derivatisation procedures than benzoyl chloride and other detectors.

Wine Microbial Spoilage: Advances in Defects Remediation

Abstract Despite good modern winemaking practices, microbial contaminations can occur. Therefore, quality wine production requires attention to possible sources of contamination during winemaking and aging. Spoilage microorganisms besides affecting wine healthiness can be unsafe for human consumption, by producing biogenic amines (BA) and precursors of ethyl carbamate. The main spoilage microorganisms include species and strains of yeasts, lactic acid bacteria, and acetic acid bacteria. Defects include bitterness, off-flavors, and sensory visual faults, such as film formation, turbidity, viscosity, and sediments. Filamentous fungi may be responsible for depreciating wine quality by the production of mycotoxins. Strains selection for performing alcoholic and malolactic fermentations, gathering the best oenological characteristics, may be the first step for achieving wines with good quality. In addition, the ability of detoxifying mycotoxins and BA must be an additional strain selection criterion for winemaking. Optimization of fining treatments will also be necessary, to remove off-odor, mycotoxins, or BA from wine.

Data on changes in red wine phenolic compounds, headspace aroma compounds and sensory profile after treatment of red wines with chitosans with different structures

Data in this article presents the changes on phenolic compounds and headspace aroma abundance of a red wine spiked with 4-ethylphenol and 4-ethylguaiacol and treated with a commercial crustacean chitin (CHTN), two commercial crustacean chitosans (CHTB, CHTD), one fungal chitosan (CHTF), one additional chitin (CHTNA) and one additional chitosan (CHTC) produced by alkaline deacetylation of CHTN and CHTB, respectively. Chitin and chitosans presented different structural features, namely deacetylation degree (DD), average molecular weight (MW), sugar and mineral composition (“Reducing the negative sensory impact of volatile phenols in red wine with different chitosan: effect of structure on efficiency” (Filipe-Ribeiro et al., 2018) [1]. Statistical data is also shown, which correlates the changes in headspace aroma abundance of red wines with the chitosans structural features at 10 g/h L application dose.

Holistic and sustainable approach for recycling and valorization of polyvinylpolypyrrolidone used in wine fining

Polyvinylpolypyrrolidone (PVPP) is a synthetic water-insoluble polymer widely used as fining agent in the wine industry for removing low-molecular-weight phenolics. Used PVPP, estimated in 2014 of 1037 tons, ends up in the municipal wastewater treatment plants with a detrimental environmental impact. Recycling of PVPP for obtaining fully reusable PVPP and wine phenolic concentrates for the food, cosmetic, and pharmaceutical industries would increase the sustainability of its use. An ammoniacal solution of ethanol allows one to desorb with high recoveries (average 73%) the PVPP adsorbed phenolics with yields ranging from 2.82 to 10.80 g/kg of wet PVPP, depending on the wine. Extracts were nearly pure concerning the phenolics abundance (>89%), without need of further purification. The performance of the recycled PVPP for white wine fining was not significantly different from that of the new PVPP, which can be recycled at least four times without loss of fining performance and allow a good recovery of adsorb...

4-Ethylphenol, 4-ethylguaiacol and 4-ethylcatechol in red wines: Microbial formation, prevention, remediation and overview of analytical approaches

ABSTRACT The presence of 4-ethylphenol, 4-ethylguaiacol and 4-ethylcatechol in red wines affect negatively their aroma conferring horsy, barnyard, smoky and medicinal aromatic notes. These volatile phenols formed from free hydroxycinnamic acids and their ethyl esters by Dekkera/Brettanomyces yeasts, can contaminate wines. Their formation can cause serious negative economic impact to the wine industry worldwide as consumers tend to reject these wines. For these reasons various preventive and remedial treatments have been studied. This review summarises the wine microbial volatile phenols formation, preventive measures during winemaking and remedial treatments in finished wines along with their advantages and limitations for dealing with this sensory defect and impact on wine quality. Also it is important to control the levels of volatile phenols in wines using fast and convenient analytical methods namely with a detection limit below their olfactory perception threshold. The analytical methods available for quality control and performance characteristics as well their advantages and disadvantages when dealing with a complex matrix like wine are discussed in detail.