• Energy Research

Grape production is highly responsive to weather conditions and therefore very sensitive to climate change. To evaluate how viticulture in the traditional Italian wine region Emilia-Romagna could be affected by climate change, several bioclimatic indices describing the suitability for grapevine production were calculated for two future periods (2011–2040 and 2071–2100) using CORDEX (Coordinated Regional Climate Downscaling Experiment) high-resolution climate simulations under two Representative Concentration Pathways (RCP) scenarios—RCP 4.5 and RCP 8.5. The projections for both of the RCP scenarios showed that most of the Emilia-Romagna region will remain suitable for grape production during the period 2011–2040. By the end of the twenty-first century, the suitability to produce grapes in Emilia-Romagna could be threatened to a greater or smaller extent, depending on the scenario. During the period 2071–2100, the entire Emilia-Romagna region will be too hot for grape production under the RCP 8.5 scenario. Under the RCP 4.5 scenario, changes will be milder, suggesting that the Emilia-Romagna region could still be suitable for grape cultivation by the end of the twenty-first century but would likely require certain adjustments.

In this experiment, the effect of pulsed electric field (PEF) technology on the extractability of anthocyanins and polyphenols in early-harvested Sangiovese red grapes (16.9°Bx sugar, 3.26 pH, and 10.4 g/L titratable acidity) from Emilia Romagna (Italy) was investigated. Electric field strengths were in the range of 0.9–3 kV/cm, generated by the application of short, high-voltage pulses, and the grapes were subjected to specific energies from 10.4 to 32.5 kJ/kg immediately after crushing and destemming to produce a pre-fermentative pulsed electric field treatment on a pilot scale. Grape musts and wines were analyzed for color components and polyphenols content from pressing of juices up to 3 months from the end of the fermentation of wines. Furthermore, the freshly-fermented wines were subjected to accelerated aging conditions (i.e., warming under 40 °C for 32 days) to simulate the evolution of color parameters with time. The color intensity was generally higher in treated musts and wines compared to the control, further increased by raising the intensity of the electric field. Results suggested the potentialities of pulsed electric fields (PEFs) as a mild pre-fermentative process to assist maceration and to increase the polyphenolic content of musts obtained by early-harvested Sangiovese grapes.

The winemaking process generates a large amount of residues such as vine shots, stalks, grape pomace, and wine lees, which were only recently considered for exploitation of their valuable compounds. The purpose of this work was to investigate the performance of nanofiltration for the recovery of phenolic compounds, with bioactive capacity like antioxidant, from red grape pomace extract. Four membranes were compared in this study—three cellulose acetate (CA series: lab-prepared by phase inversion) and one commercial (NF90). All membranes were characterized for their hydraulic permeability and rejection coefficients to reference solutes like saccharose, glucose, raffinose, polyethylene glycol, sodium chloride, and sodium sulfate. Permeation flowrates and rejection coefficients towards total phenolics content, antioxidant activity, proanthocyanidins, glucose and fructose were measured in the nanofiltration of grape pomace extract using selected operating conditions. Among the investigated membranes, the CA400-22 exhibited the highest permeate flux (50.58 L/m2 h at 20 bar and 25 °C), low fouling index (of about 23%), the lowest rejection coefficients towards the reference solutes and the best performance in terms of separation between sugars and phenolic compounds. Indeed, the observed rejections for glucose and fructose were 19% and 12%, respectively. On the other hand, total phenolics content and proanthocyanidins were rejected for 73% and 92%, respectively.

The quality of wine is mainly determined during the alcoholic fermentation that gradually transforms the grape juice into wine. Along this process the yeast goes through several stressful stages which can affect its fermentative ability and industrial performance, affecting wine quality. Based on their actual application on industrial winemaking, commercial Saccharomyces cerevisiae strains (EC1118, QA23, VIN7 and VL3) were used. They were inoculated in batch laboratory fermentations in a model wine solution for evaluating the production of reactive oxygen species (ROS) during the yeast's alcoholic fermentation. For first time total hydroperoxides were determined by FOX-1 assay to follow ROS generation. The total hydroperoxides accumulated along the 10 days of fermentation peaked up to 10.0 μM in yeast EC1118, of which 1.3 μM was hydrogen peroxide (H2O2). The FOX-1 based analytical approach herein presented is a valuable tool for the quantification of ROS oxidative damage during winemaking.

In the presented work, daily observations of minimum and maximum temperatures and precipitation-spatially interpolated in a high-resolution grid (5 x 5 km)-were used to detect climate shifts in the viticultural appellation areas of the Emilia-Romagna (ER) region, in the periods 1961-1990 and 1986-2015. The growing season (April to October) minimum, mean, and maximum temperatures were significantly increased in the second period compared to the first over the majority of the ER. Precipitation did not differ significantly, with the exception of certain small northeastern areas of the ER. The detected changes affected the ER viticultural environment in several ways: (1) an increase in the number of days with maximum temperature exceeding 30 degrees C, which can induce plant stress; (2) changes in starting and ending dates of the climatologically defined growing season, dates of the first fall frost and the last spring frost, and length of the frost-free period; (3) shifts of most vineyard areas from 'Region 2/Region 3' to 'Region 3/Region 4' (according to the Winkler Index); (4) shifts of the majority of the grape-producing zones from 'temperate/warm temperate' to 'warm temperate/warm' (according to the Huglin Index); (5) de creased availability of soil water, which is necessary for grapevine development.

In recent years, climate change has led to higher grape must sugar content and, consequently, increased alcohol by volume. Evaporative or pertraction is a common method for post-fermentation ethanol removal from wines, but it selectively removes some less polar volatile compounds along with ethanol. To mitigate volatile substance loss, this study investigates blending of the red wine (Marzemino-Cabernet blend) with obtained dealcoholized samples from it by industrial evaporative pertraction system, while maintaining the final product within a two-percentage-point reduction in ethanol. Thus MIX 1 and MIX 2 blends were prepared, reducing the ABV of the initial wine (12.5% alcohol by volume) to 10.5% and 9.5%. Chemical analyses highlighted that most alcohols, acetates, and ethyl esters of fatty acids decreased with alcohol by volume reduction. However, compounds with polar groups (acetoin and acetovanillone), C13-norisoprenoids, and certain lactones showed increasing trends. Sensory analysis indicated high scores for sweetness and smoothness in the blended wines, with a decrease in acidic taste. Floral scents notably increased, particularly in MIX 2, closely resembling the initial wine's sensory profile. The blending of initial wine with appropriately dealcoholized wine samples has proven to be an effective strategy for preserving bouquet and color of dealcoholized wines. This approach broadens the consumer base by catering to people who prefer low-alcohol options, have dietary restrictions, or are health-conscious, but who still wish to savor wines with aromatic quality rather than a flat taste. This strategy is crucial in the wine industry as it successfully addresses technical challenges and ensures economic viability.