Alternative fining of Sangiovese wine: effect on phenolic substances and sensory characteristics

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Effect of different enological tannins on oxygen consumption, phenolic compounds, color and astringency evolution of aglianico wine

Background: In the wine industry, in addition to condensed tannins of grape origin, other commercial tannins are commonly used. However, the influence of oxygen uptake related to different tannin additions during the post fermentative phase in wine has not been completely investigated. In this study, we evaluated the influence of four different commercial tannins (namely, condensed tannins, gallotannins, ellagitannins and tea tannins) during four saturation cycles. Method: Wine samples were added with four different tannin classes (30 g/hL) as to have 5 different experimental samples: control, gallotannins (GT), condensed tannins (CT), ellagitannins (ET), and tea tannins (TT). The chemical composition of the four commercially available tannin mixtures was defined by means of NMR and high-resolution mass spectrometry. After the addition of tannins, each wine sample was oxidized by air over four cycles of saturation. During the experiment oxygen consumption rate (OCR), sulfur dioxide consumption, acetaldehyde production, phenolic compounds, chromatic characteristics, astringency measured by the reactivity towards saliva proteins and astringency subqualities were evaluated. Results: The experiment lasted 52 days. The addition of tannins influenced the oxygen consumption on the 1st day of the saturation cycles and, in the case of TT, a higher total consumption of oxygen was also detected. Acetaldehyde increased during the experiment while the native anthocyanins decreased throughout the oxidation process. Conclusion: Wines added with tannins featured improved color intensities with respect to the control; the addition of TT, GT and ET slightly promoted the formation of short polymeric pigments; the astringency, determined before and at the end of the experiment, decreased in all the samples, including the control wine, and mostly in the ET and GT samples

The management of dissolved oxygen by a polypropylene hollow fiber membrane contactor affects wine aging

Background: Numerous oenological practices can cause an excess of dissolved oxygen in wine, thus determining sensory and chromatic defects in the short‐ to long‐term. Hence, it is necessary to manage the excess of oxygen before bottling. Methods: In this study, the management of the dissolved oxygen content by a polypropylene hollow fiber membrane contactor apparatus was performed in two wines from different grape varieties (Aglianico and Falanghina). The wines were analyzed after an 11‐month aging. Anthocyanins and acetaldehyde content were evaluated by HPLC. In addition, other phenolic compounds and chromatic characteristics were analyzed by spectrophotometric methods. NMR and HR ESIMS analyses were conducted to evaluate the amount of pyranoanthocyanins and polymeric pigments. Results: After 11 months of aging, in both wines a decrease of free and total SO2 with respect to initial values was detected. In the wines with the highest dissolved oxygen levels, a more remarkable loss was observed. No significant differences in terms of color parameters were detected. In red wine with the highest oxygen content, a massive formation of polymeric pigments and BSA reactive tannins was observed, as opposed to wines with lower oxygen levels. Conclusion: The study demonstrated that the membrane contactor can prove a successful tool to manage dissolved oxygen in wines as to prevent their oxidative spoilage. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Salivary Protein-Tannin Interaction: The Binding behind Astringency

Interactions between salivary proteins and tannins are at the basis of one of the main mechanisms involved in the perception of astringency. Astringency is a tactile sensation evoked in the mouth by plant polyphenol-derived products, such as red wine. It is generally recognised that tannins can provoke negative sensations such as shrinking, drawing, or puckering of the epithelium. On the other hand, the astringency of some red wines can be felt as pleasant mouth feelings of richness, fullness, mouth-coating, and velvet in the mouth. In this chapter, an overview of the research concerned with molecular and sensory mechanisms of astringency was updated. Because of many variables influence the perception of astringency, several methods have been developed to measure the intensity of the sensation. In this context, different indirect assessments were critically evaluated considering the pros and contras and correlated with sensory analysis. We focused the attention on the saliva precipitation index (SPI), based on the binding and precipitation of human saliva with grape and wine tannins, because it has been widely used for many applications in winemaking. A current great challenge is to have an in vitro measurement of astringency able to provide information on the fate of wine, from grape to bottle

Wood powders of different botanical origin as an alternative to barrel aging for red wine

AbstractWood powders are produced in large quantity as by-product of barrel, staves and chips industry. Differently from larger particles (chips), the use of wood powders in winemaking is not admitted (Regulation (CE) n. 934/2019); however, it could represent a cheap and sustainable alternative for the accelerated aging of red wine. To evaluate their potential use in winemaking, a comparative study on the use of wood powders from oak, chestnut and acacia wood for the accelerated aging of red wine (cv. Aglianico) was conducted. This alternative aging was compared to the aging in wood barrels from the same botanical species. The wine aged in contact with powders underwent a quicker evolution of polyphenolic fraction. After 15 days of contact, the loss of total anthocyanins was higher than that observed after 6 months of aging in barrels (from 4 to 14% with respect to the corresponding kind of barrel). The amount of polymeric pigments tannins–anthocyanins–tannins in wines aged in contact with powders was higher respect to the wines aged in barrels (from 7 to 21% with respect to the corresponding kind of barrel), while the greatest loss of total tannins was detected in the oak barrels (28% less with respect to the control). There were several differences in wine phenolic acids due to wood botanical origin, with the clearest differences being between oak and the alternative wood species (chestnut and acacia). Also, there was a significant botanical effect on sensory profiles. Indeed, both among barrels and among powders, oak wood was the one that gave the strongest wood odor character. However, all the treatments with wood powders (oak, acacia and chestnut) preserved the fruity character of wine, conferring in the meanwhile non-dominant woody notes

Performance of a protein extracted from potatoes for fining of white musts

In this study, the potentiality of Patatin (P), a protein extracted from potato, as must fining agent was investigated on musts obtained from two South Italy grape cultivars (Falanghina and Greco). Besides P, fining agents as bentonite (B) and potassium caseinate (C) were assayed at different concentrations. The rate of sedimentation, the decline of turbidity during time, the absorbance at 420 nm, the GRP (grape reaction products) and hydroxycinnamic acids (HCA) concentrations were determined. The comparative trials showed that P is a suitable fining agent to prevent browning and decrease haze during must settling because its effect on grape phenolics, brown pigments and turbidity is comparable and/or better than that detected for C. Its use as single fining agent or in combination with B depends on must characteristics

Astringency subqualities and sensory perception of Tuscan Sangiovese wines

Aim: The Sangiovese grape cultivar is at the basis of the most well-known Italian wines produced in the Tuscany region. However, little is known about the sensory characteristics of Tuscan Sangiovese wines, and the diversity in astringency subqualities has never been investigated. In this study we evaluated the sensory perception of 16 commercial Sangiovese wines belonging to four categories of denomination (Chianti DOCG, CH; Chianti Classico DOCG, CC; Morellino di Scansano DOCG, MS; Toscana IGT, TS), and again after 20 months of bottle aging.Methods and results: A sensory evaluation was made, consisting of the astringency subqualities, taste, odor, and aroma profiles of wines. In addition, chemical analyses were carried out for the base parameters, polyphenols and some volatile compounds. Astringency subqualities varied depending on the percentage of Sangiovese in wines (from 80 % to 100 %). Blended Sangiovese wines were characterized by positive mouthfeel sensations. According to these, the drivers of liking the wines were associated with soft, mouthcoat, and rich subqualities. The Tuscan Sangiovese denominations were differentiated by volatile active compounds, whereas after about two years of bottle aging the astringency subqualities better achieved this task. Moreover, aging also influenced the evolution of wines: CC and CH wines positively evolved, revealing a complex odor profile; MS lost the fruity character; and TS was less involved in sensory modification. Conclusions: For the first time, a detailed evaluation of the astringency subqualities of commercial Sangiovese wines was undertaken. Sangiovese subqualities differed according to the percentage of Sangiovese and denomination. Tuscan denominations were distinguished by peculiar sensory characteristics. In addition, bottle aging significantly influenced the evolution of the sensory perception of Sangiovese wine. In particular, mono-varietal Sangiovese wine needed a long period of aging to soften the astringency characteristics.Significance and impact of the study: Sangiovese wine represents - with its denominations and styles - the best-known and high-quality Italian wine in the world, and its popularity is increasing worldwide. Tuscan Sangiovese wines are often a blend with other red varieties of the region, and these can vary according to the production regulations. This study aimed to improve the knowledge of the sensory characteristics of Sangiovese wines belonging to different denominations and made with different percentages of this grape cultivar. In particular, the astringency subqualities are fundamental to fully appreciating the quality of the red wine during tasting

Biochemical features of native red wines and genetic diversity of the corresponding grape varieties from Campania Region

Campania region has always been considered one of the most appreciated Italian districts for wine production. Wine distinctiveness arises from their native grapevines. To better define the chemical profile of Campania autochthonous red grape varieties, we analysed the phenolic composition of Aglianico di Taurasi, Aglianico del Vulture, Aglianico del Taburno, Piedirosso wines, and a minor native variety, Lingua di Femmina in comparison with Merlot and Cabernet Sauvignon, as reference cultivars. A genetic profiling was also carried out using microsatellite molecular markers with high polymorphic and unambiguous profiles. Principal component analysis applied to 72 wines based on the 18 biochemical parameters, explained 77.6% of the total variance and highlighted important biological entities providing insightful patterns. Moreover, comparison of SSR-based data with phenylpropanoid molecules exhibited a statistically significant correlation. Our approach might be reasonably adopted for future characterisations and traceability of grapevines and corresponding wines

Impact of 5-year bottle aging under controlled oxygen exposure on sulfur dioxide and phenolic composition of tannin-rich red wines

Aim: This study aims at understanding the impact of the initial phenolic composition on the evolution of red wines after long bottle aging.Materials and results: three different red wines rich in tannins, Aglianico, Casavecchia and Pallagrello, bottled with the same amount of total sulfur dioxide and different amounts of free sulfur dioxide, were analysed after 5 years of bottle aging under controlled exposure to oxygen passing through the closure. Acetaldehyde and monomeric anthocyanins were determined by HPLC, the chromatic characteristics and the main phenolic classes by spectrophotometry, the saliva precipitation index (SPI) by CHIP electrophoresis, and the astringency subqualities by sensory analysis. The results confirmed that during aging there is an increase in polymerisation reactions. A higher amount of acetaldehyde was detected in wines which were bottled with a lower content of free SO2 and were less rich in anthocyanins and tannins; a significant closure effect was observed for these wines. Regarding the influence of closure on tannins, significant slight differences in vanilline reactive flavans and SPI content were observed for Pallagrello wines only, which were characterised by higher values for tannins at bottling. Astringency subqualities differed with closures for each wine.Conclusion: this study indicates that the amount of initial free and combined sulfur dioxide, as well as that of anthocyanins and tannins, are key factors in driving polymerisation reactions and the aging of red wines. After five years of bottle aging the influence of closure could still be observed.Significance of the study: this study provides new insights into the parameters that need to be evaluated before bottling in order to avoid the wrong evolution of red wines after long bottle aging

Phenolic Profiles of Red Wine Relate to Vascular Endothelial Benefits Mediated by SIRT1 and SIRT6

Dietary phenolic compounds possess potent bioactivity against inflammatory pathways of chronic inflammatory conditions, such as type 2 diabetes. Here, the phenolic profile and bioac-tivity of Italian red wines Gaglioppo, Magliocco, and Nerello Mascalese were characterized. NMR, HPLC/UV-Vis and spectrophotometric characterization showed that Magliocco was the richest wine in monomeric anthocyanins (two-fold), catechins, and low molecular weight phenolics (LMWP). A positive correlation was observed between the polyphenolic content and antioxidant capacity (p < 0.05), with Magliocco displaying the highest antioxidant capacity (p < 0.01). In vitro evidence on the endothelial cell models of insulin resistance and hyperglycemia showed the ability of Magliocco to reduce reactive oxygen species (ROS) (p < 0.01) and cytokine release (p < 0.01) and to upregulate SIRT1 and SIRT6 (p < 0.01). On the whole, the results indicated that the quantitative and qualitative phenolic profiles of red wines influence their in vitro beneficial effects on oxidative and proinflammatory milieu in endothelial cells, showing a positive modulation of SIRT1 and SIRT6, both implied in vascular aging