Effect of Commercial Mannoprotein Addition on Polysaccharide, Polyphenolic, and Color Composition in Red Wines

Commercially available mannoprotein preparations were tested in Tempranillo winemaking to determine their influence on polysaccharide, polyphenolic, and color composition. No effect was found in the content of grape arabinogalactans, homogalacturonans, and type II rhamnogalacturonans. In contrast, mannoprotein-treated samples showed considerably higher values of high-molecular-weight mannoproteins (bMP) than controls from the beginning of alcoholic fermentation, although these differences diminished as vinification progressed. The bMP decrease observed in the mannoprotein-treated samples coincided with a substantial reduction in their proanthocyanidin content and wine stable color, suggesting a precipitation of the coaggregates mannoprotein-tannin and mannoprotein-pigment. Contrary to what is widely described, these results revealed that at the studied conditions, mannoproteins did not act as stabilizing colloids. Mannoprotein addition did not modify the content and composition of either monomeric anthocyanins or other monomeric phenolics, and it did not affect monomeric anthocyanin color. © 2008 American Chemical Society

Maceration Enzymes and Mannoproteins: A Possible Strategy To Increase Colloidal Stability and Color Extraction in Red Wines

Different strategies were adopted to achieve increases in color stability in Tempranillo wines: (i) addition of maceration enzymes directly to the must, (ii) addition of commercial mannoproteins to the must, and (iii) inoculation of must with yeast overexpressed of mannoproteins. The addition of enzymes favored color extraction, and the wines obtained presented higher values of wine color, color intensity, bisulfite-stable color, and visually enhanced color intensity. The enzyme hydrolytic activity produced an increase in the acid polysaccharide content and polyphenol index and yielded to wines with more astringency, tannin, and length. Added mannoproteins had clearer effects on the analyzed parameters than yeast. Contrary to what may be thought, mannoproteins did not maintain the extracted polyphenols in colloidal dispersion and neither ensured color stability. These compounds clearly modified the gustative structure of the wines, enhancing the sweetness and roundness. © 2007 American Chemical Society

Effect of the presence of lysated lees on polysaccharides, color and main phenolic compounds of red wine during barrel ageing

A practice in wineries is to age wine in the presence of lysated lees instead of fresh lees, in order to reduce the time wine is conserved on lees and avoid possible microbiological and organoleptic risks caused by lees. Two treatments were used to induce lees lysis: acidification and acidification in combination with a mixture of -glucanases and pectinases. Acidification treatment in combination with enzymes induced significantly greater mannoprotein and glucan release. The presence of lysated lees during wine storage in barrels produced wines with significantly different tannin contents. The ageing technique on lysated lees by acidification in combination with enzymes produced wines with more intense colors, lower luminosity and saturation, and a slight tendency towards red tones, and an increase in sweetness, fullness and mouth length. On the contrary, ageing technique on lysated lees by acidification increased wine acid and fresh sensations. © 2010 Elsevier Ltd

Changes in the color components and phenolic content of red wines from Vitis Vinífera L. Cv. "Tempranillo" during vinification and aging

Changes in phenolics and color components during vinification and aging of Tempranillo wines were studied. Different phenolics display different diffusion into the must, and with the exception of proanthocyanidins and acetyl-glucoside anthocyanins, with maximum concentration at the end of postmaceration, the rest of the unacylated and coumarated anthocyanins, monomeric flavanols, and hydroxycinnamic acids reached their maximum at the end of alcoholic fermentation. This resulted in a significant increase in both wine color and stable color, mainly due to the formation of copigmentation complexes, although polymeric pigment formation was also important. Malolactic fermentation produced a significant decrease in flavonoid content while nonflavonoid concentrations were maintained, prompting a considerable loss in wine color, despite the dramatic increase in bisulfite-stable color. Wine oak aging did not produce any significant change in the studied parameters, while bottle aging reduced the level of monomeric anthocyanins and flavanols, and hydroxycinnamic acids. However, wine color remained stable due to a significant increase in stable color. Polymerization reactions of anthocyanins prevailed over pigment degradation reactions, and copigmentation was still relevant after 2 years of bottle aging. © 2008 Springer-Verlag

Quantitative determination of wine polysaccharides by gas chromatography-mass spectrometry (GC-MSD) and size exclusion chromatography (SEC)

Wine polysaccharides play an important role on a number of technological and quality properties of wines and thus several methods have been proposed for their quantification. The present study evaluates the suitability of gas chromatography with mass spectrometry detector (GC-MS) for determining the content of wine monosaccharides and thus polysaccharide families. Factors affecting the yield of polysaccharide precipitation were firstly evaluated and the GC-MS method was characterised and compared with the previously reported GC-FID method. Repeatability and reproducibility values were similar in both methods, with values ranging from 1% to 14%. LODs obtained by MS were below 1.0 g for all monosaccharides and LOQs were below 1.8 g. Moreover, a recovery study of the whole method was carried out and it provided absolute recoveries between 81% and 116% for different wine samples, very good values taking into account the multi-step procedure. Both GC-MS and GC-FID were applied to determine the content of wine polysaccharide families in three wine samples and no significant differences were observed. Finally, high-resolution size exclusion chromatography with refractive index detector (HRSEC-RID) was applied to obtain the molecular weight distributions of the wine polysaccharides and to estimate their global content. The correlation observed between the polysaccharide values obtained with the GC method and the HRSEC-RID method (r = 0.746, p < 0.05) indicated that the latter could serve as a rapid and simple method to give an estimation of total wine polysaccharides although it can not be used to quantify in a precise way. © 2011 Elsevier Ltd. All rights reserved

Analysis of polymeric phenolics in red wines using different techniques combined with gel permeation chromatography fractionation

A multiple-step analytical method was developed to improve the analysis of polymeric phenolics in red wines. With a common initial step based on the fractionation of wine phenolics by gel permeation chromatography (GPC), different analytical techniques were used: high-performance liquid chromatography-diode array detection (HPLC-DAD), HPLC-mass spectrometry (MS), capillary zone electrophoresis (CZE) and spectrophotometry. This method proved to be valid for analyzing different families of phenolic compounds, such as monomeric phenolics and their derivatives, polymeric pigments and proanthocyanidins. The analytical characteristics of fractionation by GPC were studied and the method was fully validated, yielding satisfactory statistical results. GPC fractionation substantially improved the analysis of polymeric pigments by CZE, in terms of response, repeatability and reproducibility. It also represented an improvement in the traditional vanillin assay used for proanthocyanidin (PA) quantification. Astringent proanthocyanidins were also analyzed using a simple combined method that allowed these compounds, for which only general indexes were available, to be quantified. © 2005 Elsevier B.V. All rights reserved

Changes in polysaccharide composition during sparkling wine making and aging

The evolution in polysaccharide composition and molecular weights during sparkling wine making and aging was studied for the first time in this work. Different autochthonous grape varieties from Spain (Verdejo, Viura, Malvasía, Albarín, Godello, Garnacha and Prieto Picudo) were used to elaborate sparkling wines following the champenoise method. Principal component analysis showed differentiation of wines according to polysaccharide families. This differentiation was due to the process of aging on yeast lees, but not to the variety employed. The content of mannoproteins during aging was positively correlated (r = 0.792) with total polysaccharides from grapes. After six months of aging the highest content of mannoproteins and polysaccharides rich in arabinose and galactose was obtained. Also a shift to lower molecular weights was observed. The combination of these two characteristics could imply a better foam stability and thus sensory quality of sparkling wines. © 2013 American Chemical Society

Characterization of phenolic composition of Vitis vinifera L. ‘Tempranillo’ and ‘Graciano’ subjected to deficit irrigation during berry development

The response of phenolic composition of skins from Vitis vinifera L. ‘Tempranillo’ and ‘Graciano’ grapes to water-deficit irrigation during berry growth and ripening was evaluated. The study was carried out using container-grown grapevines grown under controlled conditions in a greenhouse. Two irrigation treatments were imposed: control (well-watered) and sustained deficit irrigation (SDI). Twenty-eight phenolic compounds, including anthocyanins, flavonols and monomeric flavan-3-ols (catechins) as well as phenolic acids derivatives have been identified in the extracts prepared from the berry skins at physiological maturity. For both varieties, water deficit reduced leaf area and leaf area to crop mass ratio, and decreased berry size. However, there were no changes in juice total soluble solids, pH or total polyphenolic content. Water deficit resulted in decreased must titratable acidity in ‘Graciano’ berries. In ‘Tempranillo’, water limitation reduced total anthocyanins and flavonols, and increased hydroxycinnamic acids. In ‘Graciano’, water deficit resulted in increased flavonols and reduced catechins. Altogether, we concluded that under water-deficit irrigation, ‘Graciano’ grapes presented a differential composition of phenolic compounds that could result in improved fruit quality

First-line eradication rates comparing two shortened non-bismuth quadruple regimens against Helicobacter pylori: an open-label, randomized, multicentre clinical trial

OBJECTIVES: Helicobacter pylori eradication remains a challenge. Non-bismuth-based quadruple regimens (NBQR) have shown high eradication rates (ER) elsewhere that need to be locally confirmed. The objective of this study was to compare the first-line ER of a hybrid therapy (20 mg of omeprazole twice daily and 1 g of amoxicillin twice daily for 10 days, adding 500 mg of clarithromycin twice daily and 500 mg of metronidazole every 8 h for the last 5 days; OA-OACM) with that of a 10 day concomitant regimen consisting of taking all four drugs twice daily every day (including 500 mg of metronidazole every 12 h; OACM). A 10 day arm with standard triple therapy (OAC; 20 mg of omeprazole/12 h, 1 g of amoxicillin/12 h and 500 mg of clarithromycin/12 h) was included. PATIENTS AND METHODS: Three hundred consecutive patients were randomized (1: 2: 2) into one of the three following regimens: (i) OAC (60); (ii) OA-OACM (120); and (iii) OACM (120). Eradication was generally confirmed by a [(13)C]urea breath test at least 4 weeks after the end of treatment. Adverse events and compliance were assessed. EudraCT: 2011-006258-99. RESULTS: ITT cure rates were: OAC, 70.0% (42/60) (95% CI: 58.3-81.7); OA-OACM, 90.8% (109/120) (95% CI: 85.6-96.0); and OACM, 90.0% (107/119) (95% CI: 84.6-95.4). PP rates were: OAC, 72.4% (42/58) (95% CI: 60.8-84.1); OA-OACM, 93.9% (108/115) (95% CI: 89.5-98.3); and OACM, 90.3% (102/113) (95% CI: 84.8-95.8). Both NBQR significantly improved ER compared with OAC (P < 0.01), but no differences were seen between them. Mean compliance was elevated [98.0% (SD = 9.8)] with no differences between groups. There were more adverse events in the quadruple arms (OACM, 65.8%; OA-OACM, 68.6%; OAC, 46.6%; P < 0.05), but no significant differences between groups in terms of severity were seen. CONCLUSIONS: Hybrid and concomitant regimens show good ER against H. pylori infection with an acceptable safety profile. They clearly displace OAC as first-line regimen in our area