The Generation of Suspended Cell Wall Material May Limit the Effect of Ultrasound Technology in Some Varietal Wines.

The disruptive effect exerted by high-power ultrasound on grape cell walls enhances phenolic extraction, improving chromatic characteristics during red wine maceration. However, short maceration times may, sometimes, hinder this enhancement, and this effect could be attributed to the suspended cell wall material formation facilitated by sonication. This suspended material, having a strong affinity for phenolic compounds, can lead to their precipitation and elimination during subsequent vinification stages and, consequently, a significant portion of extracted phenolic compounds may not contribute to the final phenolic composition of the wine, impacting its chromatic features. To demonstrate this effect, sonicated grapes of two different varieties were vinified with No modified process that eliminated part of this suspended material. Results confirm our hypothesis; that is, the lack of positive outcomes in some cases is due to phenolic compound adsorption on suspended material.

The technology of high-power ultrasound and its effect on the color and aroma of rosé wines.

BACKGROUND: The application of high-power ultrasound (US) has been studied extensively to obtain value-added red wines using short maceration times. It is a technique of wide interest for the extraction of aromatic compounds and compounds responsible for color, so it could also be an important tool to use in the elaboration process of rosé wines. Thus, this study focused on the effect of the application of US on the phenolic, aromatic, and sensorial profile of rosé wines. For this, three different types of rosé wine were produced: a control with direct pressing after crushing, another wine obtained from a 4 h macerated must, and a wine whose crushed and destemmed grape was sonicated and subsequently pressed. RESULTS: The results showed a higher color intensity and a higher total polyphenol and anthocyanin content in the wine obtained from sonicated grape compared to both control wine and that obtained from grape macerated for 4 h. Ultrasound treatment enhanced the extraction of varietal volatile compounds in must, especially the free faction of terpenes and norisoprenoids. It also gave rise to wines with a higher concentration of C6 alcohols and other compounds such as guaiacol and 4-vinylguaiacol, but led to fewer fatty acids, especially C6, C4 and C8 acids. Sensorially these wines showed intense aromas of red fruits and flowers, while no defects in aroma or astringency were found. CONCLUSIONS: The color and sensory profile of the resulting wines indicate that the US may be an interesting tool for obtaining quality rosé wines, replacing the maceration stage and reducing potential oxidation problems. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Application of Ultrasound and Enzymes Could Be Promising Tools for Recovering Polyphenols during the Aging on Lees Process in Red Winemaking.

The final concentration of phenolic compounds in wines is usually lower than what might be expected, given their concentration in grapes. This is in part due to the interactions between cell walls from grapes and yeast with phenolics during red winemaking. Most of these aggregates are insoluble and end up precipitating, forming part of the lees. The objective of this study is to determine the capacity of ultrasounds and/or enzymes treatments (ß-glucanase and a pectolytic enzyme) to release the anthocyanins and tannins adsorbed in the lees. The ultrasound (US) applied for 120 min slightly favored the extraction of anthocyanins and doubled tannin extraction. Shorter sonication times did not show any positive effect. The combination of ß-glucanase and pectolytic enzyme was always more effective in the liberation of anthocyanins (both no-acylated and acylated anthocyanins) and tannins than the enzymes acting separately. The combination of US (120 min), ß-glucanase and pectolytic enzyme showed an additive effect, increasing the extraction of phenolic compounds with respect to the individual treatments and also releasing a large quantity of low molecular weight polysaccharides, compounds of enological importance. These results of this study could be of enological interest, facilitating and accelerating the aging on lees process, through the liberation of polysaccharides and the recovery of the phenolic compounds lost during vinification.