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Background: With this research an inertizing and cooling process for grapes cryomaceration has been set up. The process in question has been performed by an innovative plant that cooled the grapes rapidly in about 8 sec until they reached the set cryo-maceration temperature, using direct injection of liquid CO2. It works with a grape flow of approximately 2-3 tons/h, with a maximum thermal gradient of 20 K between the grape inlet and outlet temperature. For this plant a vibrating device was set up that allowed that only one grape cluster layer to be formed on the ribbon conveyor after the grapes had been put into the feedbox. A numerical model was set up for the cooling tunnel, and numerical simulations were performed to investigate the operative parameters of the machine in question. The numerical results were validated by means of experimental tests

This research aimed to determine the effects of cryo-maceration at different temperatures on polyphenol content during the winemaking process of Chardonnay wine. Samples of Chardonnay grapes were subjected to rapid cooling processes by direct injection of liquid CO2 to obtain final temperatures of 10.0, 8.0, 6.0 and 4.0 °C and yield different batches of grape mash. Subsequently, each batch underwent the winemaking process to produce four different wines. The wines obtained were characterized by chemical analyses. We observed higher extraction of polyphenolic compounds with low-temperature cold maceration, particularly when the temperature was reduced from 10.0 to 6.0 °C. Conversely, when the temperature was reduced below 6.0 °C, the increase in polyphenol content in wine was negligible, whereas CO2 consumption increased. Furthermore, a numerical simulation was performed to determine the pipe length, L0, after which the temperature was constant. This condition is very important because it guarantees that after the length L0, the thermodynamic exchange between liquid CO2 and is complete, eliminating the possibility of liquid CO2 pockets in the cyclone.

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<p style="text-align: justify;"><strong>Aims</strong>: Tests were carried out to assess the effects of early defoliation, cluster thinning and cluster cutting on the basic and nutritional composition of musts and wines of <em>Vitis vinifera</em> L. cv. Montepulciano.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Both production and quality variables of the musts were evaluated. Antioxidant activity was determined on berries and on wines, as were the phenol and anthocyanin concentrations. The wines were compared by sensory evaluation. The results attested to a positive effect of the treatments on grape composition and on antioxidant activity in the berries.</p><p style="text-align: justify;"><strong>Conclusions</strong>: The tested treatments (<em>DP</em> = early defoliation; <em>D3</em> = cluster thinning 30 %; <em>D5</em> = cluster thinning 50 %; <em>T3</em> = cluster cutting 30 %; <em>T5</em> = cluster cutting 50%) increased both the soluble solids and the pH of the musts and enhanced the nutritional quality (based on antioxidant concentration) of both the grapes and the wine.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The adopted techniques may be useful in cases in which yield control is required and/or the composition of the musts and wines needs to be modified based on the concentration of sugars in the berries. However, the variable response of the vines to the various techniques suggests that each cultural practice be evaluated in relation to specific oenological objectives.</p>