Sulfur free red wines through the use of grapevine shoots: Impact on the wine quality

Following a preliminary study to determine the possibility of using a grapevine shoot extract (VIN) as a sustainable alternative to sulfur dioxide (SO₂), in this study, the chromatic features, phenolic composition, and sensory analysis of wines treated with VIN at two concentrations were studied during storage in bottle for the first time. The highest differences were found in phenolic compounds after 12months of storage in bottle. The VIN wines had a low content of free anthocyanins and were high in vinyl-pyranoanthocyanins, and B-type vitisins. Consequently, they showed better chromatic characteristics. Moreover VIN, especially at high dose, preserved non-anthocyanin phenolic compounds better than SO₂. However, at this high dose some organoleptic properties were affected. VIN, when used at a low dose, is able to preserve wine composition without loss of quality.

Daily Preharvest UV-C Light Maintains the High Stilbenoid Concentration in Grapes

The fact that it is possible to induce stilbenoid synthesis in grapevine (Vitis vinifera) by UV-C light allows the possibility of stimulating grapevine phytoalexin production to increase disease resistance and immunity, and subsequently to limit the use of pesticides in vineyards. UV-C light was applied daily during three days before the harvesting of table grape variety Crimson seedless to study the accumulation of stilbenoid compounds during ripeness. The E-resveratrol concentration was monitored during daily preharvest UV-C light application and compared with that after a single application. Daily periodic preharvest UV-C light treatment showed a cumulative effect on grape stilbenoids. An 86-fold stilbenoid level increase (sum of E-resveratrol, E-piceatannol, ε-viniferin, E-piceid, isorhapontigenin, ω-viniferin, and Z-piceid) in grapes was achieved. The effects of UV-C light on stilbenoid in grape cane was also addressed for the first time. Stilbenoid oligomers such as hopeaphenol, ampelopsin A, and r-viniferin were quantified in cane samples. Quality grape parameters indicated an acceleration of ripening in UV-C samples.

Preharvest methyl jasmonate and postharvest UVC treatments: increasing stilbenes in wine

Stilbene-enriched wine is considered to be an interesting new food product with added value due to its potential health-promoting properties. Stilbene concentration in grape is highly variable and rather scarce. However, it can be increased by stress treatments. For this reason, numerous pre- and postharvest grape treatments, and some combinations of them, have been tested to maximize stilbene content in grapes. In the present manuscript, Syrah grapes were treated with (i) methyl jasmonate (MEJA), (ii) ultraviolet light (UVC), and (iii) methyl jasmonate and ultraviolet light (MEJA-UVC) and compared with untreated grapes. Afterward, winemaking was developed. Wine achieved by combination of both treatments (MEJA-UVC) contained significantly higher stilbene concentration (trans-resveratrol and piceatannol) than its respective control (2.5-fold). Wine quality was improved in color-related parameters (color intensity, L*, a*, b*, ΔE*, anthocyanins, and tannin). Moreover, MEJA-UVC wines obtained the highest score in sensorial analysis. To the best of our knowledge, this is the first time that pre- and postharvest treatments are combined to increase stilbenes in wine.

PRACTICAL APPLICATION

The effect of treatment combination (methyl jasmonate and UVC light) on grape and wine was evaluated. Our results highlight the positive effect of the treatments in stilbene content, color parameters, and sensorial analysis. Moreover, added-value by-products were achieved.

Ultrasound-assisted extraction of stilbenoids from grape stems

A new method for fast determination of stilbenoids from grape stems was developed. Ultrasound-assisted extraction was applied prior to chromatographic determination of stilbenoids in the extracts, and the stability of stilbenoids under extraction conditions was checked. A fractional experimental design was developed to analyze the influence on the extraction process of seven different extraction variables: temperature, ultrasound amplitude, ultrasonic cycle duration, ultrasonic probe type, time, sample-solvent ratio, and solvent (mixtures of ethanol and water). The most important variables for the recovery of major stilbenoids were studied and the final conditions optimized. With this new method, the main stilbenoids found in grape stems can be extracted in 15 min, using 75 °C as the extraction temperature and 80% ethanol as the extraction solvent, and no cleaning step with organic solvent is needed. The optimized method allowed for the analysis of stilbenoid content from 22 grape stem samples, many of them analyzed for the first time.

Application of insoluble fibers in the fining of wine phenolics

The application of animal-derived proteins as wine fining agents has been subject to increased regulation in recent years. As an alternative to protein-based fining agents, insoluble plant-derived fibers have the capacity to adsorb red wine tannins. Changes in red wine tannin were analyzed following application of fibers derived from apple and grape and protein-based fining agents. Other changes in wine composition, namely, color, monomeric phenolics, metals, and turbidity, were also determined. Wine tannin was maximally reduced by application of an apple pomace fiber and a grape pomace fiber (G4), removing 42 and 38%, respectively. Potassium caseinate maximally removed 19% of wine tannin, although applied at a lower dose. Fibers reduced anthocyanins, total phenolics, and wine color density, but changes in wine hue were minor. Proteins and apple fiber selectively removed high molecular mass phenolics, whereas grape fibers removed those of both high and low molecular mass. The results show that insoluble fibers may be considered as alternative fining agents for red wines.

Wine, Resveratrol and Health: A Review

Several studies have cited the Mediterranean diet as an example of healthy eating. In fact, the Mediterranean diet has become the reference diet for the prevention of cardiovascular disease. Red wine seems to be an essential component of the diet, since moderate consumption of wine is associated with lower risk and mortality from cardiovascular disease. Evidence is also accumulating that wine helps prevent the development of certain cancers. Of all the many components of wine, resveratrol, which is a natural component specifically present in wine, has been identified as being mainly responsible for these health-promoting properties. Many valuable properties such as cardioprotective and anticarcinogenic activity have been attributed to resveratrol; however, its bioavailability is quite low. The bioactivity of metabolites derived from resveratrol, and the accumulation of resveratrol in vital organs are still under study, but there are high expectations of positive results. Other stilbene compounds are also considered in this review, despite being present in undetectable or very small quantities in wine. The present paper reviews all aspects of the health properties of wine, bioactive compounds found in wine, and their concentrations, bioavailability and possible synergistic effects.

Wine, resveratrol and health: a review

Several studies have cited the Mediterranean diet as an example of healthy eating. In fact, the Mediterranean diet has become the reference diet for the prevention of cardiovascular disease. Red wine seems to be an essential component of the diet, since moderate consumption of wine is associated with lower risk and mortality from cardiovascular disease. Evidence is also accumulating that wine helps prevent the development of certain cancers. Of all the many components of wine, resveratrol, which is a natural component specifically present in wine, has been identified as being mainly responsible for these health-promoting properties. Many valuable properties such as cardioprotective and anticarcinogenic activity have been attributed to resveratrol; however, its bioavailability is quite low. The bioactivity of metabolites derived from resveratrol, and the accumulation of resveratrol in vital organs are still under study, but there are high expectations of positive results. Other stilbene compounds are also considered in this review, despite being present in undetectable or very small quantities in wine. The present paper reviews all aspects of the health properties of wine, bioactive compounds found in wine, and their concentrations, bioavailability and possible synergistic effects.