 IVES 9 IVES Conference Series 9 Influence of short-time skin maceration combined with enzyme treatment on the volatile composition of musts from fresh and withered fiano winegrapes

Influence of short-time skin maceration combined with enzyme treatment on the volatile composition of musts from fresh and withered fiano winegrapes

Abstract

AIM: The increasing market competitiveness is promoting the production of special dry wines with distinctive characteristics, obtained either from minor winegrape varieties and/or the inclusion of partially dehydrated grapes. With the aim of taking advantage of the grape quality traits in terms of aroma potential, short-time skin contact prior pressing in combination with the use of exogenous enzymes can facilitate the release of volatile organic compounds (VOCs) into the grape must. In addition, the possible presence of glycosidase activity enhances the hydrolysis of odourless glycosidically-bound precursors, which have a particular importance for non-aromatic grape varieties. [1,2] In this study, the effect of eight enzyme treatments with different single activity during short-term pre-fermentative maceration was investigated on the volatile composition of musts, obtained from both fresh and withered winegrapes cv. ‘Fiano’.

METHODS: The study was carried out on fresh or partially dehydrated (20% of weight loss) ‘Fiano’ white winegrapes from Campania region (southern Italy). For each sample, twenty-seven berry sets of 500 g each were randomly selected and crushed in presence of 10 mg/kg of potassium metabisulphite. Then, three berry sets were individually treated with pectin lyase (PL), polygalacturonase (PG), pectin methylesterase (PME), xylanase (XYL), arabinase (ARA), protease (PRO), β-glucanase (GLN), or β-glucosidase (GLU) enzymes at a dose of 10 mg/kg, homogenized and subjected to pre-fermentative maceration for 13 h at 12 °C. The other three berry sets were treated similarly but without enzyme addition (control). Subsequently, the musts obtained were separated from the skins and used for the determination of free and glycosidically-bound VOCs using solid-phase extraction followed by GC-MS analysis [3].

RESULTS: Regarding the free volatile fraction of musts, few compounds were influenced by the different enzyme treatments tested. This effect appeared to be more evident for glycosylated volatile compounds, for which the concentration of total compounds, aromatic alcohols, C6 alcohols, and certain terpenes (nerol and geraniol) significantly prevailed in musts from fresh grapes treated with PG. Moreover, samples from withered Fiano grapes treated with PG and ARA were characterized by higher contents of terpenes (cis-8-hydroxylinalool, nerol, geraniol, and α-terpineol), C6 alcohols (trans-2-hexenol and 1-hexenol), and benzenoids (eugenol).

CONCLUSIONS:

The addition of enzymes during short-term pre-fermentative maceration resulted to have effect mainly on the glycosylated volatile fraction of the musts obtained from fresh and withered grapes. In particular, exogenous enzyme activities such as PG exhibit major influence on the volatile profile of musts derived from fresh and withered ‘Fiano’ grapes, which could contribute to enhance the sensory perceived aroma of the resulting wines.

DOI:

Publication date: September 10, 2021

Issue: Macrowine 2021

Type: Article

Authors

Stefano Boz

University of Torino, Italy,Susana RÍO SEGADE, University of Torino, Italy Stefano BOZ, University of Torino, Italy Mattia MALABAILA, University of Torino, Italy Domen ŠKRAB, University of Torino, Italy Maria Alessandra PAISSONI, University of Torino, Italy Simone GIACOSA, University of Torino, Italy Luca ROLLE, University of Torino, Italy

Contact the author

Keywords

volatile compounds; enzymes; pre-fermentative maceration; fiano winegrapes

Citation

Optimizing stomatal traits for future climates

Stomatal traits determine grapevine water use, carbon supply, and water stress, which directly impact yield and berry chemistry. Breeding for stomatal traits has the strong potential to improve grapevine performance under future, drier conditions, but the trait values that breeders should target are unknown. We used a functional-structural plant model developed for grapevine (HydroShoot) to determine how stomatal traits impact canopy gas exchange, water potential, and temperature under historical and future conditions in high-quality and hot-climate California wine regions (Napa and the Central Valley). Historical climate (1990-2010) was collected from weather stations and future climate (2079-99) was projected from 4 representative climate models for California, assuming medium- and high-emissions (RCP 4.5 and 8.5). Five trait parameterizations, representing mean and extreme values for the maximum stomatal conductance (gmax) and leaf water potential threshold for stomatal closure (Ψsc), were defined from meta-analyses. Compared to mean trait values, the water-spending extremes (highest gmax or most negative Ysc) had negligible benefits for carbon gain and canopy cooling, but exacerbated vine water use and stress, for both sites and climate scenarios. These traits increased cumulative transpiration by 8 – 17%, changed cumulative carbon gain by -4 – 3%, and reduced minimum water potentials by 10 – 18%. Conversely, the water-saving extremes (lowest gmax or least negative Ψsc) strongly reduced water use and stress, but potentially compromised the carbon supply for ripening. Under RCP 8.5 conditions, these traits reduced transpiration by 22 – 35% and carbon gain by 9 – 16% and increased minimum water potentials by 20 – 28%, compared to mean values. Overall, selecting for more water-saving stomatal traits could improve water-use efficiency and avoid the detrimental effects of highly negative canopy water potentials on yield and quality, but more work is needed to evaluate whether these benefits outweigh the consequences of minor declines in carbon gain for fruit production.

Ozone treatment: a solution to improve sanitary and physiological quality of vine plant

The vineyard world is faced to a lot of fungal diseases. Grapevine Trunk Diseases (GTD) are some of the major. After exhibiting chronical foliar symptoms, grapevines can die by apoplexy within only few days. A range species of fungi was described to be associated with the apparition of early symptoms of GTD. It is well known that ozone dissolved into water is a powerful disinfectant with no remanence. The main goal of this study was to test the efficiency of this process on different fungal species associated with GTD in vitro and in planta conditions.

Chitosan elicits mono-glucosylated stilbene production and release in fed-batch fermentation of grape cells

In the present study, the optimal conditions of grape (Vitis vinifera cv ‘Barbera’) cell cultures in batch and fed-batch bioreactor processes were studied to specifically improve the production of mono-glucosylated stilbenes.

Viticulture, landscapes and the marketing of our wine

The global wine market is polarising over brands versus origin. Provenance is emerging as a marketing megatrend in many fast moving consumer goods. Origin has always been important in wine but does that mean consumers understand, or care about terroir?

Authenticating the geographical origin of wine using fluorescence spectroscopy and machine learning

Wine is a luxury product and a global beverage steeped in history and mystery. Over time, various regions have become renowned for the quality of wines they produce, which adds considerable value to the regions and the brands. On the whole, the international wine market is worth many hundreds of billions of dollars, which attracts unscrupulous operators intent on defrauding wine consumers.