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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 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 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.

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

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 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 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 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.