Evaluation of Aglianico grape skin and seed polyphenols astringency by SDS-PAGE electrophoresis of salivary proteins after the binding reaction

SDS–PAGE electrophoresis and densitometry analysis were carried out to evaluate the reactivity of Aglianico red grape skin and seed polyphenols with human salivary proteins in order to find a method able to assess their astringency. Analysis of the supernatant obtained after a tannin/human salivary protein binding assay and sensorial analysis showed that four proteins, lactoferrin, PRPbg1, PRPbg2 and a-amylase, were the proteins best able to distinguish tannin solutions characterised by different levels of astringency. A correlation between densitometric data and tannin concentration was plotted in order to give an indirect measure of astringency. The two sources of Aglianico grape polyphenols differed from each other in astringency power; the seed extract solution was about two-fold more tannic than the skin one. The difference in astringency was also perceived by sensorial analysis. The results from this study show that SDS–PAGE electrophoresis of human salivary proteins after the binding reaction with grape polyphenol extracts, coupled with densitometric analysis and the use of a calibration curve, looks extremely promising as a new approach to evaluate polyphenol astringency

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

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

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

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

Potential for lager beer production from saccharomyces cerevisiae strains isolated from the vineyard environment

Saccharomyces pastorianus, genetic hybrids of Saccharomyces cerevisiae and the Saccharomyces eubayanus, is one of the most widely used lager yeasts in the brewing industry. In recent years, new strategies have been adopted and new lines of research have been outlined to create and expand the pool of lager brewing starters. The vineyard microbiome has received significant attention in the past few years due to many opportunities in terms of biotechnological applications in the winemaking processes. However, the characterization of S. cerevisiae strains isolated from winery environments as an approach to selecting starters for beer production has not been fully investigated, and little is currently available. Four wild cryotolerant S. cerevisiae strains isolated from vineyard environments were evaluated as potential starters for lager beer production at laboratory scale using a model beer wort (MBW). In all tests, the industrial lager brewing S. pastorianus Weihenstephan 34/70 was used as a reference strain. The results obtained, although preliminary, showed some good properties of these strains, such as antioxidant activity, flocculation capacity, efficient fermentation at 15◦C and low diacetyl production. Further studies will be carried out using these S. cerevisiae strains as starters for lager beer production on a pilot scale in order to verify the chemical and sensory characteristics of the beers produced

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

Oleanolic acid: A promising antidiabetic metabolite detected in Aglianico grape pomace

Grape pomace, a bulky component of winery waste, is a source of healthy compounds. So far, scientific research has mainly focused on its polyphenol content, but given the impressive number of bioactivities shown by grape pomace, it is not unlikely that, besides polyphenols, additional metabolites, so far undetected, may be involved. In order to verify such hypothesis, an in-depth chemical analysis of Aglianico (Vitis vinifera) grape pomace was conducted by NMR and LC-MS/MS. In addition to a number of polyphenols, a remarkable concentration of oleanolic acid (0.45 mg/g - fresh weight) was determined in the analyzed material. Oleanolic acid is a natural triterpenoid showing many bioactivities including antitumor, anti-inflammatory, antibiotic and antiviral properties. Also, it was proven a potential antidiabetic molecule in Type1 Diabetes rats. Hence, its influence on the mitochondrial and glucose uptake activities of C2C12 myoblast was here assessed, thus supporting oleanolic acid as a promising antidiabetic metabolite