Publications by authors named "Ana Belén Bautista-Ortín"

20 Publications

  • Page 1 of 1

Revisiting the use of pectinases in enology: A role beyond facilitating phenolic grape extraction.

Food Chem 2021 Oct 1;372:131282. Epub 2021 Oct 1.

Department of Food Science and Technology, Faculty of Veterinary Sciences, University of Murcia, 30100 Murcia, Spain.

With the objective of improving both the extraction of phenolic compounds from grapes and their maintenance in the final wine, we compared the effect of favoring phenolic extraction with a pectolytic-based maceration enzyme with that of favoring both phenolic extraction and the partial elimination of the suspended material using a pectolytic-based clarification enzyme. The phenolic composition of the final wines and those adsorbed to the precipitated lees were analyzed. Both enzymes increased wine color intensity and phenolic content, but the best results were observed when the clarification enzyme was used. This enzyme generated the largest losses of phenolics bound to precipitated lees. However, this resulted in a positive effect, the precipitation of lees rich in phenolic compounds probably created a pronounced gradient of phenolic compounds from grapes to must/wine and better chromatic characteristics in the final wine, compared with the wine made using a traditional maceration enzyme.
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http://dx.doi.org/10.1016/j.foodchem.2021.131282DOI Listing
October 2021

Effect of Sonication Treatment and Maceration Time in the Extraction of Polysaccharide Compounds during Red Wine Vinification.

Molecules 2021 Jul 23;26(15). Epub 2021 Jul 23.

Instituto de Ciencias de la Vid y del Vino (Universidad de la Rioja, Gobierno de La Rioja y CSIC), Finca La Grajera, 26007 Logroño, Spain.

The application of high-power ultrasounds (US) at 28 kHz to the crushed grapes and the use of different pomace contact times caused changes in the content and composition of monosaccharides and polysaccharides in the musts and wines. These differences were maintained from the moment of pressing (end of maceration) until the end of the alcoholic fermentation. The US increased the content of monosaccharides and polysaccharides in the musts by facilitating their extraction from the solid parts during maceration. The application of medium maceration time (3 days) to sonicated grapes led to an extraction of polysaccharides rich in arabinose and galactose, rhamnogalacturonan type II (RG-II) and mannoproteins (MP), similar to that observed in the control wines made with an extended maceration of 7 days (968.21 vs. 1029.45; 895.04 vs. 1700.50; 356.81 vs. 343.95, respectively). This fact was attributed to a higher extraction in the must during the sonication process and to an important release of pectic polysaccharides during the pressing of the sonicated pomace, which is reported here for the first time. Therefore, the US technology could be useful for increasing the polysaccharide content in the wines or for reducing the maceration time needed to achieve certain levels of wine polysaccharides.
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http://dx.doi.org/10.3390/molecules26154452DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8348054PMC
July 2021

Ultrasound treatment of crushed grapes: Effect on the must and red wine polysaccharide composition.

Food Chem 2021 Sep 23;356:129669. Epub 2021 Mar 23.

Department of Food Science and Technology, Faculty of Veterinary Science, University of Murcia, Campus de Espinardo, 30071 Murcia, Spain.

This paper studied the effect on the molecular weight and polysaccharide composition of musts and wines of the application of high-power ultrasound (US) at 20 and 28 kHz on crushed grapes. Two different pomace maceration times (short and mid) were tested for sonicated and control vinifications. A long pomace maceration time was also tested for non-treated wines. In must samples, US significantly increased the content of monosaccharides and polysaccharides rich in arabinose and galactose (PRAG), and the average molecular weight of smaller PRAG, mannoproteins (MP) or mannans. The 28 kHz had a major effect on most wine monosaccharides and grape polysaccharides. The wine obtained from sonicated grapes at 28 kHz and with mid maceration had higher rhamnogalacturonans type II and PRAG content than its control, and closer polysaccharide and monosaccharide content to long maceration control wines. No significant differences were obtained in the MP content between sonicated and control wines.
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http://dx.doi.org/10.1016/j.foodchem.2021.129669DOI Listing
September 2021

Effect of Power Ultrasound Treatment on Free and Glycosidically-Bound Volatile Compounds and the Sensorial Profile of Red Wines.

Molecules 2021 Feb 23;26(4). Epub 2021 Feb 23.

Area of Food Technology, Faculty of Chemical Sciences and Technologies, Regional Institute for Applied Scientific Research (IRICA), University of Castilla-La Mancha, Avda. Camilo José Cela 10, 13071 Ciudad Real, Spain.

This study presents the effect of the application of high-power ultrasound to crushed grapes, at a winery-scale, on the content of varietal volatile compounds (free and glycosidically-bound) in musts and on the overall aroma of wines. Two different frequencies (20 kHz and 28 kHz) were tested and the combination of grape sonication and different maceration times on wine aroma was also evaluated. The volatile compounds were isolated by solid phase extraction and analyzed by gas chromatography-mass spectrometry, carrying out a sensory evaluation of wines by quantitative descriptive analysis. Sonication produced an increase in the concentration of free varietal compounds such as C alcohols, terpenes and norisoprenoids in musts and also in wines made by 48 h of skin maceration, being less efficient in the extraction of the bound fraction. Fermentation compounds were also positively affected by ultrasound treatment, although this effect was variable depending on the frequency used, the maceration time and the type of compound. All the wines made from sonicated grapes had better scores in the evaluated olfactory attributes with respect to the control wines. Our results indicate that sonication could produce an increase in the content of some volatile compounds of sensory relevance, obtaining wines with an aroma quality similar or higher than those elaborated with longer maceration times.
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http://dx.doi.org/10.3390/molecules26041193DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7926635PMC
February 2021

Changes in Skin Flavanol Composition as a Response to Ozone-Induced Stress during Postharvest Dehydration of Red Wine Grapes with Different Phenolic Profiles.

J Agric Food Chem 2020 Nov 5;68(47):13439-13449. Epub 2020 Oct 5.

Department of Food Science and Technology, Faculty of Veterinary, University of Murcia, 30071 Murcia, Spain.

In this study, the combined effect of partial postharvest dehydration and long-term ozone treatment was evaluated at 10 and 20% weight loss as a strategy to induce compositional changes in grape skin flavanols. Two separate trials were carried out in thermohygrometric-controlled chambers at 20 °C and 70% relative humidity. The first trial was conducted under an ozone-enriched atmosphere at 30 μL/L, whereas the second trial was performed under an air atmosphere as a control. Two red wine grape varieties were studied, Barbera and Nebbiolo ( L.), for their different phenolic composition. Berry skin flavanol composition was determined by high-performance liquid chromatography after phloroglucinolysis and size-exclusion chromatography. The results showed that dehydration and ozone effects were variety-dependent. In Barbera skins, being characterized by lower proanthocyanidin contents, the two effects were significant and their combination showed interesting advantages related to lower proanthocyanidin loss as well as higher prodelphinidin and lower galloylation percentages. In Nebbiolo, skin flavanol composition was barely affected.
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http://dx.doi.org/10.1021/acs.jafc.0c04081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8015211PMC
November 2020

Evaluating Alternatives to Cold Stabilization in Wineries: The Use of Carboxymethyl Cellulose, Potassium Polyaspartate, Electrodialysis and Ion Exchange Resins.

Foods 2020 Sep 11;9(9). Epub 2020 Sep 11.

Department of Food Science and Technology, Faculty of Veterinary Sciences, University of Murcia, Campus de Espinardo, 30100 Murcia, Spain.

The tartaric stabilization of wines before bottling to avoid the precipitation of tartaric acid salts is an important and common step during wine production. The presence of precipitated salt crystals in bottled wines is detrimental to their quality and can even be a legal issue in some countries. Different methodologies are used in wineries to substitute the classical low-temperature stabilization process, which is an effective but costly process. This study comprises two years of experiments with red wines at an industrial scale. In the first year of the experiment, two subtractive methods (ionic exchange resins and electrodialysis) were tested, whereas two additive methods (potassium polyaspartate and carboxymethyl cellulose, both of them containing gum Arabic) were tested the second year. The tartaric stability of the wines, together with the oenological, chromatic and sensory characteristics, were followed during one year in the bottle. The results indicate that carboxymethyl cellulose and potassium polyaspartate (both combined with gum Arabic) were best at maintaining the sensory and chromatic characteristics during storage, with potassium polyaspartate providing a good tartaric stability to the treated wine and this wine being, in general, preferred in a sensory analysis test.
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http://dx.doi.org/10.3390/foods9091275DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7554854PMC
September 2020

A New Approach to the Reduction of Alcohol Content in Red Wines: The Use of High-Power Ultrasounds.

Foods 2020 Jun 2;9(6). Epub 2020 Jun 2.

Department of Food Science and Technology, Faculty of Veterinary Sciences, University of Murcia, Campus de Espinardo, 30100 Murcia, Spain.

Background: To obtain wines with a lower percentage of alcohol, the simplest approach would be an earlier harvest of the grapes. However, this has implications for the wine composition and quality, due to the lack of phenolic maturity that these grapes may present. A technological innovation that could help in this situation could be the use of ultrasound in wineries.

Methods: Grapes were harvested with two different ripening levels (25.4 °Brix and 29 °Brix), transported to the winery, and vinified. Also, a large-scale high-power ultrasound system was used to treat part of the less mature grapes just after crushing. These grapes were also vinified. The three different vinifications were skin-macerated for 7 days. The wine aroma compounds and physicochemical, chromatic, and sensory characteristics were analyzed at the time of bottling.

Results: The wine made with the ultrasound-treated grapes showed very similar characteristics to the wine made with the more mature grapes, especially regarding total phenol and tannin content, but with an alcohol content 15% lower than the latter.

Conclusions: The results indicate that this technology could be applied to grapes to favor the extraction of grape phenolic compounds, even when grape phenolic maturity is not complete, allowing the production of quality wines with a reduced alcohol content.
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http://dx.doi.org/10.3390/foods9060726DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353473PMC
June 2020

The Role of Soluble Polysaccharides in Tannin-Cell Wall Interactions in Model Solutions and in Wines.

Biomolecules 2019 12 25;10(1). Epub 2019 Dec 25.

Department of Food Science and Technology, Faculty of Veterinary Science, University of Murcia, Campus de Espinardo, 30100 Murcia, Spain.

The interactions between tannins and soluble and insoluble cell wall components are, in part, responsible for the low quantities of tannins found in wines compared with the quantities in grapes. The use of polysaccharides to compete with cell wall components could be an interesting approach for improving the chromatic and sensory characteristics of wines. The effect of two commercial polysaccharides, pectin and mannan, on limiting tannin-cell wall interactions was studied in a model solution, measuring the concentration of tannins and polysaccharides remaining in solution after the different interactions by chromatography. The treatment was also tested in a small-scale vinification. Soluble polysaccharides were added to the must and the wines were evaluated at the end of alcoholic fermentation and after six months in the bottle. In the model solution, the commercial polysaccharides formed soluble complexes with the tannins and limited the interactions with cell wall components, with some differences between skin and seed tannins. In the case of the wines, the treatments resulted in wines with a higher color intensity and phenolic content. Sensory analysis resulted in higher scores for the wines with added polysaccharides, since the complexation of tannins with the polysaccharides increased the roundness and body of the resulting wines.
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http://dx.doi.org/10.3390/biom10010036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7023468PMC
December 2019

Effect of the Use of Purified Grape Pomace as a Fining Agent on the Volatile Composition of Monastrell Wines.

Molecules 2019 Jul 1;24(13). Epub 2019 Jul 1.

Food Science and Technology Department. Faculty of Veterinary Science, University of Murcia, Campus de Espinardo, 30100 Murcia, Spain.

(1) Background: The lack of viable alternatives for the industrial exploitation of grape pomace is one of the reasons why it is considered a serious environmental pollutant. However, as a byproduct, it could be used as a fining agent, since previous studies have shown that it is able to eliminate undesirable substances in wine. However, the little information available does not describe its effect on wine aroma. (2) Methods: Purified grape pomace extracts were used for fining a red wine and their effect on the volatile compounds of the wine was assessed, comparing the results with those obtained with different commercial fining agents. (3) Results: The results showed how purified grape pomace decreased the total volatile content of a wine to a similar extent as other fining products, such as yeast extracts or gelatin. Among the different families of volatile compounds analyzed, only total esters and terpenes differed from the levels recorded for a control wine, being slightly lower. No statistical differences were found for the rest of the volatile compounds (alcohols, carbonyl, lactones, and acids) compared with the levels measured in control wine. (4) Conclusions: The results suggest that purified grape pomace could be used as a non-allergenic wine fining agent.
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http://dx.doi.org/10.3390/molecules24132423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6651625PMC
July 2019

Winegrapes dehydration under ozone-enriched atmosphere: Influence on berry skin phenols release, cell wall composition and mechanical properties.

Food Chem 2019 Jan 1;271:673-684. Epub 2018 Aug 1.

Università degli Studi di Torino, Dipartimento di Scienze Agrarie, Forestali e Alimentari, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy.

Gaseous ozone has been recently proposed as sanitizing agent to control mycobiota on grapes. The aim of this work was to evaluate the impact of ozone treatment during winegrapes dehydration (10 and 20% weight loss) on the content of phenolic compounds after treatment and their extractability during simulated maceration. The results showed that the ozone effect depends on the profile and content of anthocyanins and flavanols. For varieties characterized by prevalence of di-substituted anthocyanins and high flavanol contents, no significant differences were observed in phenolic compounds contents, but lower anthocyanin extractability was found. Instead, for varieties rich in anthocyanins and with a tri-substituted prevalent profile, lower anthocyanin contents were found at 20% WL, but their extractability was significantly increased. Using multivariate analysis, the extractability was correlated with skin cell wall composition and mechanical properties. Proteins, non-cellulosic glucose and total phenols contributed mainly to explain phenolic compounds extractability in withered grapes.
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http://dx.doi.org/10.1016/j.foodchem.2018.07.218DOI Listing
January 2019

Performance of purified grape pomace as a fining agent to reduce the levels of some contaminants from wine.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2018 Jun 5;35(6):1061-1070. Epub 2018 Jun 5.

a Food Science and Technology Department. Faculty of Veterinary Science , University of Murcia , Murcia , Spain.

The quality of red wine depends on the absence of compounds which may affect its safety and/or stability such as ochratoxin A, biogenic amines and some metals and trace compounds. The presence of ochratoxin A in musts and wines is due to fungal contamination of the grapes and has been classified as a possible human carcinogen. Biogenic amines are formed by the microbiological decarboxylation of the corresponding amino acid precursors during the fermentation or ageing and storage, and, at high concentrations, they may induce adverse reactions in sensitive people. Trace elements may have both a nutritional and a toxic effect on health, but also can cause turbidity and stability problems. Their presence is affected mainly by natural factors such as soil mineral content and direct contact with tank surfaces and metallic tubing during winemaking. One of the best options to remove these compounds when present in excess in wine is fining. However, some fining agents commonly used may themselves present problems related with their allergenic properties or with their propensity to increase the protein content, which can cause turbidity problems. In an attempt to avoid such these problems, purified grape pomace was tested as a fining alternative since it has been seen to have a high capacity to reduce the astringency, turbidity and also the ochratoxin A content. The main aim of this work, therefore, was to study if this material can limit the presence of ochratoxin A, biogenic amines and metals and some trace elements in a Monastrell red wine, thus increasing the value and safety of this product.
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http://dx.doi.org/10.1080/19440049.2018.1459050DOI Listing
June 2018

Anthocyanins influence tannin-cell wall interactions.

Food Chem 2016 Sep 15;206:239-48. Epub 2016 Mar 15.

Department of Food Science and Technology, Faculty of Veterinary, University of Murcia, Campus de Espinardo, 30071 Murcia, Spain. Electronic address:

The rate of tannin extraction was studied in a vinification of red grapes and the results compared with another vinification made with white grapes fermented as for typical red wine, in the presence of skins and seeds. Even though the grapes presented a quite similar skin and seed tannin content, the differences in tannin concentration between both vinifications was very large, despite the fact that the only apparent difference between the phenolic composition of both wines was the anthocyanin content. This suggests that anthocyanins play an important role in tannin extractability, perhaps because they affect the extent of the tannin-cell wall interaction, a factor that largely controls the resulting quantity of tannins in wines. To confirm this observation, the effect of anthocyanins on the tannin extractability from grape seeds and skin and on the interaction between tannins and grape cell walls suspended in model solutions were studied. The results indicated that anthocyanins favored skin and seed tannin extraction and that there is a competition for the adsorption sites between anthocyanins and tannins that increases the tannin content when anthocyanins are present.
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http://dx.doi.org/10.1016/j.foodchem.2016.03.045DOI Listing
September 2016

Tannin profile of different Monastrell wines and its relation to projected market prices.

Food Chem 2016 Aug 22;204:506-512. Epub 2016 Feb 22.

Food Science and Technology Department, Faculty of Veterinary, University of Murcia, Campus de Espinardo, 30071 Murcia, Spain.

This study focuses on the differences or similarities in tannin composition and concentration in Monastrell wines from different wineries from the same geographic area and, within each winery, from wines elaborated based on different projected market prices, to determine whether there is any relationship between the wine tannin composition and the projected price. The tannin composition of the different wines, all of them analyzed at the same point during winemaking, indicated that those elaborated as premium wines presented higher phenol and tannin contents. The mean degree of polymerization of these wines was also positively related with the projected price, which agreed with the results obtained by size exclusion chromatography, that showed that wines with high projected prices had a higher proportion of polymeric tannins, suggesting that techniques favoring the extraction of skin tannins were mostly used in those wines projected as premium wines, probably looking for greater mouthfeel complexity.
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http://dx.doi.org/10.1016/j.foodchem.2016.02.124DOI Listing
August 2016

Technological Implications of Modifying the Extent of Cell Wall-Proanthocyanidin Interactions Using Enzymes.

Int J Mol Sci 2016 Jan 18;17(1). Epub 2016 Jan 18.

Department of Food Science and Technology, Faculty of Veterinary, University of Murcia, 30071 Murcia, Spain.

The transference and reactivity of proanthocyanidins is an important issue that affects the technological processing of some fruits, such as grapes and apples. These processes are affected by proanthocyanidins bound to cell wall polysaccharides, which are present in high concentrations during the processing of the fruits. Therefore, the effective extraction of proanthocyanidins from fruits to their juices or derived products will depend on the ability to manage these associations, and, in this respect, enzymes that degrade these polysaccharides could play an important role. The main objective of this work was to test the role of pure hydrolytic enzymes (polygalacturonase and cellulose) and a commercial enzyme containing these two activities on the extent of proanthocyanidin-cell wall interactions. The results showed that the modification promoted by enzymes reduced the amount of proanthocyanidins adsorbed to cell walls since they contributed to the degradation and release of the cell wall polysaccharides, which diffused into the model solution. Some of these released polysaccharides also presented some reactivity towards the proanthocyanidins present in a model solution.
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http://dx.doi.org/10.3390/ijms17010123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4730364PMC
January 2016

Role of cell wall deconstructing enzymes in the proanthocyanidin-cell wall adsorption-desorption phenomena.

Food Chem 2016 Apr 25;196:526-32. Epub 2015 Sep 25.

Universidad de Murcia, Departamento de Tecnología de Alimentos, Nutrición y Bromatología, Facultad de Veterinaria, Campus de Espinardo, 30071 Murcia, Spain.

The transference of proanthocyanidins from grapes to wine is quite low. This could be due, among other causes, to proanthocyanidins being bound to grape cell wall polysaccharides, which are present in high concentrations in the must. Therefore, the effective extraction of proanthocyanidins from grapes will depend on the ability to disrupt these associations, and, in this respect, enzymes that degrade these polysaccharides could play an important role. The main objective of this work was to test the behavior of proanthocyanidin-cell wall interactions when commercial maceration enzymes are present in the solution. The results showed that cell wall polysaccharides adsorbed a high amount of proanthocyanidins and only a limited quantity of proanthocyanidins could be desorbed from the cell walls after washing with a model solution. The presence of enzymes in the solution reduced the proanthocyanidin-cell wall interaction, probably through the elimination of pectins from the cell wall network.
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http://dx.doi.org/10.1016/j.foodchem.2015.09.080DOI Listing
April 2016

Nutritional composition and antioxidant capacity in edible flowers: characterisation of phenolic compounds by HPLC-DAD-ESI/MSn.

Int J Mol Sci 2014 Dec 31;16(1):805-22. Epub 2014 Dec 31.

Department of Food Technology, Food Science and Nutrition, Faculty of Veterinary Sciences, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Espinardo 30071 (Murcia), Spain.

Edible flowers are commonly used in human nutrition and their consumption has increased in recent years. The aim of this study was to ascertain the nutritional composition and the content and profile of phenolic compounds of three edible flowers, monks cress (Tropaeolum majus), marigold (Tagetes erecta) and paracress (Spilanthes oleracea), and to determine the relationship between the presence of phenolic compounds and the antioxidant capacity. Proximate composition, total dietary fibre (TDF) and minerals were analysed according to official methods: total phenolic compounds (TPC) were determined with Folin-Ciocalteu's reagent, whereas antioxidant capacity was evaluated using Trolox Equivalent Antioxidant Capacity (TEAC) and Oxygen Radical Absorbance Capacity (ORAC) assays. In addition, phenolic compounds were characterised by HPLC-DAD-MSn. In relation to the nutritional value, the edible flowers had a composition similar to that of other plant foods, with a high water and TDF content, low protein content and very low proportion of total fat-showing significant differences among samples. The levels of TPC compounds and the antioxidant capacity were significantly higher in T. erecta, followed by S. oleracea and T. majus. Thirty-nine different phenolic compounds were tentatively identified, with flavonols being the major compounds detected in all samples, followed by anthocyanins and hydroxycynnamic acid derivatives. In T. erecta small proportions of gallotannin and ellagic acid were also identified.
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http://dx.doi.org/10.3390/ijms16010805DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4307276PMC
December 2014

Remarkable proanthocyanidin adsorption properties of monastrell pomace cell wall material highlight its potential use as an alternative fining agent in red wine production.

J Agric Food Chem 2015 Jan 6;63(2):620-33. Epub 2015 Jan 6.

Departamento de Tecnologı́a de Alimentos, Nutrición y Bromatologı́a, Facultad de Veterinaria, Universidad de Murcia , Campus de Espinardo, 30071 Murcia, Spain.

The existence of interactions between the polysaccharides of vegetal cell walls and proanthocyanins makes this cell wall material an interesting option for its use as a fining agent to reduce the level of proanthocyanins in wines. Pomace wastes from the winery are widely available and a source of cell wall material, and the identification of varieties whose pomace cell walls present high proanthocyanin binding capacity and of processing methods that could enhance their adsorption properties could be of great interest. This study compared the proanthocyanin adsorption properties of pomace cell wall material from three different grape varieties (Monastrell, Cabernet Sauvignon, and Syrah), and the results were compared with those obtained using fresh grape cell walls. Also, the effect of the vinification method has been studied. Analysis of the proanthocyanidins in the solution after reaction with the cell wall material, using phloroglucinolysis and size exclusion chromatography, provided quantitative and qualitative information on the adsorbed and nonadsorbed compounds. A highlight of this study was the observation that Monastrell pomace cell wall material showed a strong affinity for proanthocyanidins, with values similar to that obtained for fresh grapes cell walls, and a preferential binding of high molecular mass proanthocyanidins, so these pomace cell walls could be used in wines to reduce astringency. The use of maceration enzymes during vinification had little effect on the retention capacity of the pomace cell walls obtained from this vinification, although an increase in the retention of low molecular mass proanthocyanidins was observed, and this might have implications for wine sensory properties.
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http://dx.doi.org/10.1021/jf503659yDOI Listing
January 2015

Interactions between grape skin cell wall material and commercial enological tannins. Practical implications.

Food Chem 2014 9;152:558-65. Epub 2013 Dec 9.

Departamento de Tecnología de Alimentos, Nutrición y Bromatología, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, Murcia 30071, Spain. Electronic address:

Commercial enological tannins were used to investigate the role that cell wall material plays in proanthocyanidin adsorption. Insoluble cell wall material, prepared from the skin of Vitis vinifera L. cv. Monastrell berries, was combined with solutions containing six different commercial enological tannins (proanthocyanidin-type tannins). Analysis of the proanthocyanidins in the solution, after fining with cell wall material, using phloroglucinolysis and size exclusion chromatography, provided quantitative and qualitative information on the non-adsorbed compounds. Cell wall material showed strong affinity for the proanthocyanidins, one of the commercial tannins being bound up to 61% in the experiment. Comparison of the molecular mass distribution of the commercial enological tannins in solution, before and after fining, suggested that cell walls affinity for proanthocyanidins was more related with the proanthocyanidin molecular mass than with their percentage of galloylation. These interactions may have some enological implications, especially as regards the time of commercial tannins addition to the must/wine.
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http://dx.doi.org/10.1016/j.foodchem.2013.12.009DOI Listing
September 2014

Tannin oxidation: intra- versus intermolecular reactions.

Biomacromolecules 2010 Sep;11(9):2376-86

INRA, UMR1083 SPO, F-34060 Montpellier, France.

Grape and apple condensed tannin fractions were autoxidized at high concentrations (5 g/L) in aqueous solutions and analyzed by thiolysis (depolymerization followed by HPLC analysis) and small angle X-ray scattering (SAXS). Structural parameters of native (unoxidized) tannin polymers were derived from SAXS according to the wormlike chain model: the length per monomer is 15 A, the length of the statistical segment 17 A, and the cross section of the macromolecule has a radius within the range 3-4.5 A. The rather short length of the statistical segment is an effect of the different location of interflavanol linkages, which cause a loss of orientational correlation between successive monomers. Oxidation created new bonds that were resistant to thiolysis, and, according to thiolysis, some of these new bonds were intramolecular. However, according to SAXS, oxidation at high tannin concentration caused the weight average degree of polymerization to increase, indicating that intermolecular reactions took place as well, creating larger macromolecules. In the case of the smaller grape seed tannins, these intermolecular reactions took place "end to end" leading to the formation of longer linear macromolecules, at least in the earlier stages of oxidation. In the case of the larger apple tannins, the SAXS patterns were characteristic of larger branched macromolecules. Accordingly, the intermolecular reactions were mainly "end to middle". This is in agreement with the higher probabilities of "end to middle" reactions arising from a higher ratio extension unit/terminal unit in the latter case.
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http://dx.doi.org/10.1021/bm100515eDOI Listing
September 2010

Antioxidant activity of wine pigments derived from anthocyanins: hydrogen transfer reactions to the dpph radical and inhibition of the heme-induced peroxidation of linoleic acid.

J Agric Food Chem 2009 Jul;57(13):5762-70

UMR408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Site Agroparc, Domaine St-Paul, F-84914 Avignon, France.

The consumption of red wine can provide substantial concentrations of antioxidant polyphenols, in particular grape anthocyanins (e.g., malvidin-3-O-beta-d-glucoside (1)) and specific red wine pigments formed by reaction between anthocyanins and other wine components such as catechin (3), ethanol, and hydroxycinnamic acids. In this work, the antioxidant properties of red wine pigments (RWPs) are evaluated by the DPPH assay and by inhibition of the heme-induced peroxidation of linoleic acid in acidic conditions (a model of antioxidant action in the gastric compartment). RWPs having a 1 and 3 moieties linked via a CH(3)-CH bridge appear more potent than the pigment with a direct 1-3 linkage. Pyranoanthocyanins derived from 1 reduce more DPPH radicals than 1 irrespective of the substitution of their additional aromatic ring. Pyranoanthocyanins are also efficient inhibitors of the heme-induced lipid peroxidation, although the highly hydrophilic pigment derived from pyruvic acid appears less active.
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http://dx.doi.org/10.1021/jf900841bDOI Listing
July 2009
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