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The presence of turbidity and precipitates in the bottle causes depreciation of wine by consumers. Colloidal instability is at the basis of these phenomena. The cold treatment is a technique widely used to stabilize wines, as regards both the tartaric and the colloidal precipitations. However, it is an energy-consuming technique. In view of a sustainable management of winery practices, the work aimed at evaluating the possibility of using some enological products for the colloidal stabilization of wines without cold treatment. 8 adjuvants (sodium and calcium bentonite, hot and cold soluble gelatin, chitosan, isinglass, PVI/PVP, carboxymethylcellulose) and 4 additives (kordofan gum, 2 different mannoproteins, a natural polysaccharide polymer) were compared. The trial was performed with a Barbera (2019) and a Montepulcianod'Abruzzo (2020) wines, stabilized against tartaric precipitations without cold, but with colloidal instability. Three days after the treatments the wines were racked, filtered (3 m) and bottled. After bottling and after 6 months of bottle aging, the wines were analyzed. Colloidal stability test (48 hours at 4°C) and shock test (1 and 7 days at 40 °C) were performed. As regards Barbera, the treatment with sodium bentonite (50 g/hL) or the addition of a mannoprotein (15 g/hL) allowed to stabilize the wine. For Montepulciano, having a higher colloidal instability than Barbera, the cold stabilization resulted necessary because no treatment was effective. All treatments had a modest impact on the color.

The polyphenolic composition and antioxidant activity of grape seeds, as byproducts of red winemaking, depend on various factors, such as grape cultivar, vintage effect, grape maturity and winemaking methods. In the present work, the influence of the maceration length on the polyphenolic and antioxidant characteristics of the seeds of four Italian red grape cultivars (&lsquo, Barbera&rsquo, &lsquo, Grignolino&rsquo, Nebbiolo&rsquo, and &lsquo, Uvalino&rsquo, ), sampled from the fermentation tanks after short (two days) and medium-long (7&ndash, 21 days) macerations, was studied with spectrophotometric methods, high-performance liquid chromatography (HPLC), and three different antioxidant assays (2,2&prime, azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power (FRAP) and 2,2 diphenyl-1-picrylhydrazyl (DPPH)). The total polyphenolic content (gallic acid equivalent (GAE)) of the seeds sampled after short macerations ranged between 24.5 and 60.1 mg/g dry weight (DW), and it dropped to 20.0&ndash, 37.5 mg/g DW after medium-long macerations. The polyphenolic profile of the shortly macerated seeds was related to the varietal characteristics, while, after longer macerations, the influence of the maceration length prevailed on the cultivar effect. The multiple in vitro antioxidant activity tests (ABTS, FRAP and DPPH), although based on different mechanisms capable of highlighting behavioral differences between the different polyphenolic compounds, were highly correlated with each other and with the polyphenolic parameters, the qualitative differences between the matrices in the polyphenolic profile were probably less important than the quantitative differences in the polyphenolic content. The relations with the polyphenolic content were linear, except for the Efficient Concentration (EC20) parameter, whose relation was better described by a hyperbolic equation.

The research was aimed at verifying the efficacy of potassium polyaspartate (KPA), added at bottling, for prevention of the precipitation of potassium bitartrate (KHT). The stability of KHT was determined with the mini-contact test and the cold test. The effect of KPA on the colloidal stability of white and red wines was also studied. Turbidity, color, and total anthocyanins and flavonoids (red wines only) were monitored. In the first experiment, the stabilizing effect of KPA added at bottling, with or without Arabic gum, tannins, and filtration (0.45 µm cut-off), was studied in comparison with metatartaric acid (MTA). KPA proved to have good stabilizing efficacy for prevention of KHT precipitation and maintained its effect in all trials after 1 year of bottle aging. On the contrary, all the trials with MTA became unstable after 6 months. Moreover, KPA did not modify wine turbidity and color. The filtration (0.45 µm cut-off) did not reduce its stabilizing efficacy. In the second experiment, the effect of KPA added to a white and a red wine, respectively clarified with casein and gelatin or vegetal protein and/or bentonite, was studied. KPA did not cause any increase in turbidity or appreciable changes in the color of the white wines of the different trials. A preliminary treatment with bentonite can prevent the possible formation of haze in red wines after the addition of KPA. PRACTICAL APPLICATION: KPA prevented the precipitation of KHT in unstable white and red wines. The stabilizing effect persisted after 1 year of bottle aging. The oenologist does not need to adopt special prescriptions when using KPA in combination with Arabic gum or tannins in prebottling operations. A treatment with bentonite prevented the appearance of turbidity in red wines after the addition of KPA.

The focus of the paper is on effectiveness of a functionalization process with natural polyphenols on a chemically treated and bioactive Ti6Al4V alloy, on the grafting mechanism, and the redox/scavenging activity of the grafted biomolecules. Polyphenols (phenolic acids, flavonoids, and condensed tannins) are extracted from organic red grape pomace. The functionalization process is performed at pH = 7.4 with the addition of calcium ions, which act as a bridge between the substrate and polyphenols. The presence, amount (semi-quantitative), distribution, release, and type of bonding to the surface of the grafted polyphenols have been assessed. The functionalized samples have a homogeneous distribution of polyphenols as a continuous layer and micro-sized agglomerates. The grafted polyphenols maintain redox chemical and radical scavenging ability. A fraction of polyphenols is released into water in one day, while a firmly grafted layer remains on the surface even after four weeks. A complete release can occur in case of an environment with pH of 4–5 (e.g. inflammation). The functionalized surfaces can be sterilized by gamma irradiation without significant damage of the grafted polyphenols.

The technique of seeds removal during the fermentative maceration was conceived to limit the extraction of polyphenols from the seeds in order to reduce the natural wine astringency. The influence of this oenological practice on the polyphenolic composition of Gaglioppo wines was studied during three vintages (2010–2012): the wines produced in the presence (WS) or absence (WOS) of seeds were compared for the physicochemical, polyphenolic and volatile composition, as well as for the sensory characteristics. Seeds removal did not cause any important modification in the general physicochemical composition of wines. Regarding polyphenols, no differences in total anthocyanins content were observed between the trials, but a significantly lower total polyphenols content was observed in the WOS wines, regarding in particular total flavonoids, low molecular weight flavans and condensed tannins. Qualitative variations in the composition of condensed tannins were also observed: the WOS wines had a higher mean degree of polymerization (mDP) and a lower galloylation degree. Finally, minor differences in the aromatic profile due to the seeds removal technique were observed between the trials. Despite the important modifications of the polyphenolic composition, the sensory characteristics of the wines, on the whole, were not affected: a significant decrease of the bitter taste in the WOS trial was noticed only in vintage 2010.

Agro-industry byproducts can still contain large amounts of phenolic compounds, and one of the richest sources are grape skins and seeds as grape pomace, both fermented (red winemaking) and unfermented (white winemaking). The residual polyphenolic content depends on various factors such as grape variety, vintage, and winemaking technique. In this work, four red grape varieties cultivated in northern Italy were studied: Albarossa, Barbera, Nebbiolo, and Uvalino. The work was aimed at studying the polyphenolic composition of skins and seeds from fresh grapes and from the corresponding pomace after fermentative maceration, to assess the actual importance of the varietal differences when processing winemaking byproducts for the extraction of phenolic compounds. The skin and seed extracts were prepared by solvent extraction with a 50% hydroalcoholic solution. The polyphenolic composition of all extracts was determined by spectrophotometry and high-performance liquid chromatography (HPLC), the content and the monomer composition of condensed tannins were determined by phloroglucinolysis, the antioxidant capacity was measured with the ABTS (2,2&rsquo, azinobis-(3-ethylbenzothiazoline-6- sulfonate)) method. The antioxidant capacity was higher for the seeds than for the skins, and it was positively correlated with the condensed tannins content. Significant differences in polyphenolic composition of fresh grape skins and seeds were observed between the different cultivars. In particular, Barbera and Albarossa skins were significantly distinguished from Nebbiolo and Uvalino skins for a higher content of anthocyanins and a lower content of vanillin-reactive flavans and condensed tannins, regarding seeds, Barbera and Albarossa had a lower content of vanillin-reactive flavans, proanthocyanidins, and condensed tannins than Nebbiolo and Uvalino. The winemaking process extracted the phenolic compounds to a different extent from skins and seeds, regardless of the cultivar. The differences between cultivars in the polyphenolic profile disappeared after fermentative maceration.

The production cycle of Rectified Concentrated Must (RCM) includes a deionization phase performed with ion exchange resins, that are regenerated after each deionization cycle with strong mineral acids or strong bases. The resulting waste water is particularly rich in cations and anions removed from the must, and various processes for the recovery of tartaric acid are normally performed. More recently, new techniques have been developed for the recovery of all organic acids of the must as concentrated solutions of organic acids (SGA: Solutions of Grapes organic Acids). The work was aimed at determining the acidic profile and some specifics of SGA for a possible use as wine acidifiers. Moreover, some trials were carried out to define the correct dose of SGA to be added to wines in order to cause a given decrease of pH, equivalent to that obtained with H2T. As a result, a method was proposed for the calculation of the dose of SGA needed to determine a given decrease of wine pH. The recovery and valorization of SGA from the RCM processing cycle can represent a virtuous example of biorefinery, within the framework of the circular and green economy promoted by EU.

The management and disposal of large amounts of grape pomace (GP) annually generated by the wine industry represent a serious economic and environmental problem. On the other hand, GP can be profitably exploited for many possible purposes as a source of natural phenolic compounds. GP is highly perishable, and it is produced in large amounts during a short period of time: a rapid stabilization by drying is needed to prolong its availability for any further processing. In the case of large amounts of GP to be dried at an industrial level, the balance between costs and final quality of the dried product must be considered. The effect of high-temperature treatments (160–200 °C) for short duration on the polyphenolic composition of GP, and on its stability over time during storage, were studied separately for skins and seeds. The high-temperature treatments caused the enrichment of the polyphenolic content of the skins and the contemporary decrease in that of the seeds. Overall, the dried GP retained over time the polyphenolic composition and the anti-radical properties determined at the end of the drying process. This result is of particular interest in view of the use of dried GP throughout the year for any further processing.

The polyphenolic content and the antioxidant capacity of seven tannins with different botanical origin were measured with spectrophotometric methods (Folin-Ciocalteu, Total Polyphenols Index, DPPH, FRAP), HPLC (phloroglucinolysis), voltammetric analysis (Linear Sweep Voltammetry, LSV). The oxygen consumption rate (OCR) was measured in an oxygen saturated model wine solution, containing transition metals and metabisulphite, with a noninvasive luminescence-based technology. The results showed a high variability in polyphenolic concentration related to the botanical origin of tannins. The OCR determined over 21 days was described by quadratic equations, with coefficients varying with tannin botanical origin, dose and SO2 concentration. The tannins ranked differently for antioxidant capacity, depending on the kind of test. The oxygen consumption parameters were positively correlated only with the LSV data measured with anodic current between 100 and 1200 mV (LSV1200mV) and with the FRAP index.

All additives used to stabilize wines against the precipitations of potassium bitartrate have some limits: metatartaric acid (MTA) is effective but very unstable, carboxymethylcellulose is stable and effective in white wines but affects color stability in red wines, mannoproteins have a variable effectiveness depending on wine composition. This work was aimed at testing the effect of new stabilizing products on tartaric precipitations, focusing on the use of Na and K polyaspartate salts (PASPs). The effectiveness of 4 different PASPs and 1 MTA added to red and white wines was compared using the mini-contact test and cold test. The dose effect and the stability of the products over time were also studied. The PASPs showed a similar stabilizing effect and a longer stability over time compared to MTA. PASPs can be considered interesting as additives for wine tartaric stabilization. Further work is in progress to better characterize their enological properties.

This research investigated the effect of pressing under air or nitrogen on the color and concentration of reduced glutathione (GSH), hydroxycinnamoyl tartaric acids (HCTA) and polyphenols in the musts of four Italian white grape cultivars: Arneis, Cortese, Moscato bianco, and Manzoni bianco. Grapes from different locations were pressed using a prototype press (500 kg capacity) under the same operating conditions as a commercial winery. The musts of the four cultivars were significantly different from one another. The trend of the measured GSH concentration in the musts was: Moscato bianco

Climate change can affect the crops production capacity and modify the water requirements in the different regions of the world. In particular, in southern Europe and in the Mediterranean region the vegetative cycle of plants will take place in a warmer and drier period, with the consequent increase in vegetative activity, transpiration rate, and water consumption. In the case of vine, the rationalization of water resource needs a deep knowledge of the complex relationships between climate, soil, water availability and grape variety, in order to preserve the high quality regional wine productions. In the Cirò DOC area (Calabria), the effect of irrigation, prolonged until maturity, on the polyphenolic content of the grapes was studied with the Gaglioppo red grapes variety, in order to verify whether a moderate post-veraison water supply could favour the completion of phenolic maturation. Two different water regimes were compared in the vineyard, and the physicochemical composition, the polyphenolic and aromatic profiles and the sensory characteristics of the resulting wines were studied. The study confirmed that the climatic variability of the different vintages can influence both the vegetative-productive activity of vines and the effect of water supplies.

Three wines (a Rose wine, a Pelaverga and a Barbera red wines) were dealcoholized at 5% v/v ethanol with two different techniques: membrane contactor (MC) and distillation under vacuum (D). The influence of the treatments on the physicochemical composition and aromatic profile of the dealcoholized fractions was investigated. The main difference between the two techniques was the concentration grade reached by the dealcoholized fractions, which was 5-6times higher with D than with MC due to the concomitant loss of water. The main fixed compounds (organic acids, cations, polyphenols, anthocyanins) were not lost during the dealcoholization, while the losses of volatile compounds were relevant. Finally, the δ18O isotopic ratio was studied. The δ18O isotope ratio increased with D and decreased with MC. At the same time the δ18O isotope ratio fell within legal limits when the final ethanol content was adjusted to 2% by blending with dealcoholized fractions.

This study compared floating-cap and submerged-cap vinification techniques for making wine from the Barbera cultivar. The submerged-cap method led to less extraction of phenolics during fermentative maceration than the floating-cap method. After soft pressing (0.5 bars), both the press wine and the marcs had higher total anthocyanin concentrations with submerged cap than with floating cap (+68.6% and +79.8%, respectively). No differences were observed between two submerged-cap trials with different pumping-over cycles during fermentative maceration. Despite the lower extraction of anthocyanins and tannins, at racking off the submerged-cap wines had significantly higher concentrations of total anthocyanins and total flavonoids than the floating-cap wines. The higher losses of total anthocyanins in the floating-cap wines were likely partly due to the greater importance of the enzymatic oxidation reactions in the cap, but especially to the more important precipitations of potassium bitartrate, enhanced by the higher extraction of potassium from the skins during fermentative maceration. The submerged-cap wines were also richer in tannins. The differences between the trials became statistically significant only after the union of the free-run wine with the press wine. For total anthocyanins, tannins, and color, these differences remained significant during the first year of aging.

The influence of temperature, turbidity and oxygen uptakes to the musts on the production of ethanal by yeasts, during the alcoholic fermentation (AF), has been studied. The aim was to evaluate how increasing and controlling the production of this molecule, in order to anticipate the reactions between anthocyanins and flavans from the second half of the AF. This concerns, in particular, those winemaking techniques consisting in a temporarily separate fermentation of a part of the must (35–40% of the total mass), that is drained before the start of the AF. The experimental design was a complete factorial plan with three factors upon two levels (T = 18 °C and 22 °C; with or without oxygen; turbidity of 30 and 120 NTU); data were elaborated with 3-ways ANOVA. Temperature proved to be the main factor influencing ethanal production during AF: higher temperatures (22 °C versus 18 °C) cause an increase of the ethanal content during the first days of fermentation; after having reached 6–7% of ethanal, the effect is inverted. The influence of turbidity is less important, and it's synergic with the effect of temperature. Oxygen has a detrimental effect on the production of ethanal only at the beginning of the AF, while later, in presence of ethanol, it promotes it through a chemical way.

This work was aimed at optimizing a rapid and reproducible conductivity test for the evaluation of wine tartaric stability, in order to improve the practices for the prevention of tartaric precipitations during bottle aging. The test consists in measuring the drop of conductivity in wines kept under stirring for a fixed time, at low temperature, after the addition of micronized potassium bitartrate crystals (KHT). An experimental design was planned to study three factors affecting the test: temperature, duration and dose of added potassium bitartrate. A standard protocol was defined to produce a micronized potassium bitartrate starting from available commercial products, since the dimensions of the crystals can affect the final conductivity values. After the choice of the best conditions the method was validated. Two different stability thresholds were defined for white wines and for red/rose wines by comparing the results of the mini-contact test with those of the cold test.

The extracting effectiveness of some solvents (water, ethanol, acetone, ethyl acetate), used as pure or in binary and ternary mixtures, was studied for the extraction of seeds from the fermented pomace of Nebbiolo cv. The aqueous mixtures of acetone provided the highest extraction yields in total polyphenols and total flavonoids. Polyphenolic extracts were also obtained with aqueous mixtures of ethanol or acetone at variable concentrations, and the condensed tannins were quantified with the phloroglucinolysis method. The aqueous mixtures of acetone were more effective than the corresponding aqueous mixtures of ethanol. The solvent influenced the extraction yield and the composition of the extracts: with the increase of the yield, the mean degree of polymerization (mDP) of the condensed tannins increased. A significant correlation was noticed between mDP and the molar percentages of (+)-catechin as terminal unit (negative correlation), and of (-)-epicatechin and (-)-epicatechin-3O-gallate as extension units (positive correlation).

This work studied the effect of reduced glutathione (GSH) and/or ellagitannins added at bottling on the shelf life of a white wine with a medium/low SO2 content at two levels (−SO2 and +SO2). After 3 months of bottle aging, the trials with the higher level of SO2 (+SO2) were significantly less colored, more fruity, more soft and less bitter than the corresponding trials with the lower level of SO2 (−SO2). After 6 months, the +SO2 trials were significantly distinguished from the −SO2 trials for the more intense floral and fruity notes and the less intense oxidative notes. The addition of GSH and/or ellagitannins did not extend the shelf life of bottled wines: no complementary effects of these additives to SO2 were observed. The effect of GSH was also studied at higher levels of SO2 and two different levels of dissolved oxygen. The addition of GSH caused a significant increase in the oxygen consumption rate during the first month of bottle aging, but after 1 year, no effects on the oxidation process were observed. GSH, unlike other antioxidant additives, did not increase the consumption of SO2. GSH, like SO2, can most likely react with o-quinones but, most likely, not with the hydroperoxyl radical to yield hydrogen peroxide, which causes an increase in SO2 consumption. The rapid and almost complete loss of GSH was observed during the first months of bottle aging. The possibility of using doses of GSH > 20 mg L−1 and combining enological techniques aimed at controlling the multiple causes of wine oxidation should be taken into account.

This study was aimed at investigating the influence of ethanol, wine polyphenols and yeast extract on the volatility of 4-ethylphenols in red wines. The use of solid-phase microextraction with short extraction times for the study of the headspace composition, revealed a strong influence of ethanol and polyphenols on reducing the volatility of 4-ethylphenols in a model wine. At the same time, the influence of ethanol and polyphenols on the perception of the “Brett character” (stable, manure, horse sweat and phenolic notes) due to 4-ethylphenols was evaluated by sensory analysis. Polyphenols and ethanol were found to have a significant influence on the olfactory perception of the tainted wines. On the contrary, a direct influence of yeast extract on the volatility of 4-ethylphenols was not observed, although some results suggested that the effectiveness of polyphenols in reducing the volatility of 4-ethylphenols could be limited by the presence of yeast proteins.

The present work studied the effect of the kind of closure (a screw cap, a natural cork, and 2 synthetic closures) on the evolution of the oxygen content and on the physical-chemical and sensory characteristics of a Montepulciano d'Abruzzo rosé wine during the 1st 12 mo of bottle aging. The chemical analyses concerned the parameters more involved in the oxidative reactions (SO(2) , acetaldehyde, phenols, wine color), as well as the main fermentative volatile compounds. The kind of closure influenced the oxygen content in wines, free and total SO(2) concentration, and wine color (color intensity and hue). During bottle aging, free and total SO(2) concentration was significantly and negatively correlated with absorbance at 420 nm (A420), whereas the correlations with A520 were weak. Probably, the limited extent of the variations in red color (A520), when varying SO(2) concentration, were due to the low pH of this rosé wine. No effect of the kind of closure on phenols and the main fermentative volatile compounds was observed. The wines bottled with cork closures (N trials), after 12 mo of storage, had higher color intensity and hue, measured by spectrophotometry, and were visually distinguished from the other trials for the more intense pink reflections. On the whole, under the conditions of this work, all the used closures guaranteed a good preservability to the rosè wines during the 1st year of bottle aging, and the changes in composition did not significantly affect wine sensory characteristics. Therefore, these synthetic closures can represent an alternative to the cork closures for a medium to long term bottle aging of these wines.

A method to identify and quantify megastigmane norisoprenoid compounds in wines was developed using headspace solid phase micro extraction (SPME) coupled with gas-chromatography/mass-spectrometry (GC–MS). Three different compounds were quantified by stable isotope dilution assay (SIDA): β-damascenone, β-ionone and α-ionone. Particular attention was paid to maximising the method’s sensitivity while reducing the extraction time. To optimise the extraction conditions, a statistically designed experiment was performed using extraction time, extraction temperature and ethanol content as operating variables. Five different SPME fibres suitable for the analysis of volatile compounds were compared. This study confirmed that the PDMS/DVB coating performs best for the quantification of β-damascenone and β-ionone, and the crucial influence of ethanol content of the sample on extraction effectiveness. Finally, the optimised method was applied to the study of various wines derived from rare and autochthonous grape varieties of north-western Italy.

The present work concerns the determination of the volatile compounds, as well as the description of the olfactory characteristics, of "Langhe DOC Nebbiolo" wines produced through the prefermentative cold maceration with dry ice, on full scale (30 quintals) in private cellars. The free volatile compounds and those obtained by enzymatic and chemical hydrolysis of the glycosilated precursors were analyzed by gas chromatography-mass spectrometry. Among free volatile compounds, a loss of alcohols with 6 carbon atoms in the cryo-macerated trials was observed. The cryo-maceration technique, when correctly applied, increased the floral and fruity notes (blackberry, cherry, and plum). This increase is related to the extraction of polyphenolic compounds (maceration effect), but no volatile compounds, neither in free form, nor produced by enzymatic hydrolysis of the glycosilated precursors, can discriminate the wines according to their content of polyphenols. Only some compounds produced by chemical hydrolysis of the precursors can discriminate the wines (statistically significant differences): 3-hydroxy-β-damascone, methylvanillate, and blumenol C. These compounds, however, form during aging and do not have any influence on young wines aroma.

We report the results of an aging trial of Montepulciano d'Abruzzo D.O.C. wine in commercially available oak barrels that differed in the type of wood grain (extra fine and fine) and cooperage toasting conditions: medium (EVM), light (EVL), medium for a shorter time (CM), and, finally, a single short-time pretoasting stage at high temperature (ExpT). The chemical-physical composition, the volatile substances released by the wood, and the sensory characteristics of wines after 6 and 12 mo of aging were monitored. The differences observed were mainly in the concentration of volatile substances and the olfactory characteristics of the wines. The volatile compounds that could distinguish among the wines were the cis isomer of beta-methyl-gamma-octalactone, the ratio between cis and trans octalactone, vanillin, cyclotene, maltol, 5-methyl guaiacol, and the furfuryl compounds. The concentration of cis octalactone was influenced by the type of grain of the wood, while the cis/trans octalactones ratio varied depending on the toasting conditions used in the production of the barrels (the highest concentration was in EVL). In particular, the length of time (EVM compared with CM) and the temperature (EVM compared with EVL) of the toasting process influenced the concentration of vanillin, furfuryl alcohols, cis octalactone, and 5 methyl guaiacol. Among the olfactory descriptors, statistically significant differences were detected in the notes of caramel, toasty, spicy, green pepper, coconut, and wood.