The impact of improved technologies using inert gases at the stage of pre-fermentation must processing on the chemical composition, sensory quality and nutraceutical properties of wine

Ingredients of white and red wines can react with significant amounts of oxygen, and polyphenols are among the most easily oxidized components of wine. White wine is particularly susceptible to such practices, as its quality degrades when exposed to oxygen. Over the past twenty years, innovations in processing technology have been focused on recovering and protecting natural ingredients with high nutritional value, such as antioxidants (antioxidants).

New procedures have been developed for the production of white wines with refined taste, enriched aroma, limited browning, high stability and health properties. Currently, white grapes are processed mainly using a press membrane enabling gentle squeezing of the juice (0-2 bar, 0-2·105 Pa) to produce high-quality white wines. The slow increase in working pressure prevents crushing of the stems and limits the diffusion of phenolic compounds responsible for herbaceous aromas, bitter taste and turbidity. The phenolic compounds of white wine contribute to its sensory properties such as color, flavor, bitterness, enzymatic and non-enzymatic browning and the formation of haze due to reaction with proteins, metals and polymerization during aging. The phenolic profile of white wine is influenced by the grape variety, climate and soil, growing conditions and, of course, winemaking techniques.

The aim of the study is to determine the impact of the use of inert gases during the maceration and pressing of must in a pilot pneumatic press on the chemical composition, sensory quality and nutraceutical properties of musts and white and rosé wines.

Project activities

The implementation process was divided into several stages due to the issues of the task. The scientific research planned to be carried out will overlap - several stages have been distinguished due to the methodology of the research, which include:

1. Development of the technological process, design and construction of a prototype pneumatic press with a closed pressing system with a drum capacity of 2700 L with self-cleaning internal channels, in its entirety made of stainless steel.
2. Assessment and adjustment of environmental conditions for wine production by employees involved in the project.
3. Must adjustments will be made in farmers' wineries and wine will be produced in accordance with applicable technologies.
4. Samples of the finished wine will be taken for analytical, physicochemical and sensory tests. 
5. A sensory analysis of wines made from musts not protected against contact with oxygen and protected by noble gases will be carried out.

The main benefits of the project

The technological solutions proposed in the project will support the agricultural sector - mainly the wine sector.  

Thanks to the use of new technology, which will determine the impact of the use of inert gases during the maceration process and pressing of must in a pneumatic press on the chemical composition, sensory quality and nutraceutical properties of musts and white and rosé wines made from them. It will be possible to develop vineyards for wine production. The purchase of machinery and equipment for wine production will significantly improve the farmer's work, which is very important given the changing climatic conditions in Poland. 

Agriculture is responsible for approximately 15-20% of greenhouse gas emissions. The proposed solution, by appropriately addressing the problem of losses caused by improper wine fermentation process, is part of effective restrictions related to the rationalization of food losses and waste, as well as restrictions on the use of chemicals, therefore the introduction of such solutions is highly advisable, climate-friendly and is part of the currently in trends related to environmental protection. Cooperation in the operational group will increase knowledge in the field of viticulture and wine production. Thanks to the technologies used, the profitability of farms will increase by reducing losses caused by improper fermentation.                

Practice summary

The result of the operation will be the development and implementation of innovative wine production technology. The innovative product will be characterized by high sensory quality and nutraceutical properties. The pilot technological line, which does not require high energy expenditure, will be a technological innovation. It will allow the production of food with potential health-promoting properties.

As a result, the wines obtained in the technological process will fall into the category of natural, local food. Innovative products will be promoted through the use of marketing methods. A very important element of marketing will be the implementation of planned speeches, lectures and training. In the project, we want to develop and produce technology and a product that is high-quality wine.

Results achieved

The aim of the conducted research project was to determine the impact of using inert gases (such as nitrogen or carbon dioxide) during key stages of grape processing, namely maceration and pressing of the must, on the chemical composition, sensory quality, and nutraceutical properties of white and rosé musts and wines. The experiments were carried out using a pilot pneumatic press, which allowed precise control of process conditions and simulation of production scale in an experimental setting.  Within the scope of the project, a series of research and technological tasks were performed. Grape fermentation was conducted under controlled conditions—both in an air atmosphere (reference conditions) and in the presence of inert gases—while monitoring changes in the chemical composition of musts and wines, with particular attention to aromatic compounds, phenolics, antioxidants, and parameters such as sugar content, acidity, and sulfur levels. Simultaneously, sensory evaluation of the samples was performed by a trained panel of tasters, along with analyses of health-promoting properties, including antioxidant capacity. The project demonstrated that the application of this new technology can significantly reduce undesirable oxidation processes during maceration and pressing. This results in better preservation of aromatic compounds, higher freshness and more intense color, as well as increased nutraceutical potential of the final product. Additionally, it was shown that it is possible to limit the use of sulfur dioxide in the production process without compromising the sensory quality of the wines.

 The implementation of the project results, focused on the use of inert gases during maceration and pressing of must in pneumatic presses, brings a range of significant technological, environmental, and economic benefits that support the development of the agricultural sector, particularly the wine industry. Primarily, the proposed technology allows for a substantial improvement in the quality of produced white and rosé wines by reducing oxidation processes at the grape processing stage. This results in better preservation of natural aromas, freshness, and intensity of color, thereby enhancing the sensory value of the final products. Additionally, wines produced using inert gases demonstrate a higher nutraceutical potential, including increased antioxidant content, which aligns with growing consumer expectations for health-promoting foods. One of the key outcomes of this operation is also the possibility of reducing the use of sulfites, fitting into the trend of producing foods with fewer chemical additives and meeting the demands for sustainable and environmentally friendly production. The reduction of losses related to oxidation and improper fermentation processes directly contributes to decreasing raw material and resource wastage, thereby also reducing greenhouse gas emissions — a particularly important aspect considering that agriculture accounts for approximately 15–20% of global GHG emissions. This technology also opens new opportunities for the development of the domestic wine industry — encouraging the establishment and expansion of vineyards and investments in modern technological equipment. Purchasing winemaking machinery and devices will enable farmers to automate processes, increase labor efficiency, and adapt production to changing climatic conditions, which is crucial for the future of Polish agriculture. Another added value of the project is the development of collaboration within the operational group, which fosters the exchange of knowledge and experience regarding grape cultivation and wine production technology. Such cooperation contributes to enhancing farmers’ competencies and implementing innovative solutions at the farm level, increasing their competitiveness and profitability. In summary, the project results provide tangible support for the agricultural sector through the introduction of efficient, environmentally friendly wine production technologies that contribute to improving product quality, reducing losses, limiting chemical use, and building a stronger, more sustainable, and climate-resilient wine industry in Poland. 

Additional comments

It is important to evaluate the impact of winemaking treatments such as fermentation, fining, filtration and aging, which reduce the absolute concentration of antioxidants. Early winemaking treatments, such as skin contact and the pressure gradient applied during the pressing stage, may affect the extraction of phenolic compounds that are involved in juice oxidation and wine stability. During wine production, enzymatic and non-enzymatic oxidation of must occurs, resulting in the degradation of phenolic compounds. It results in unfavorable changes in the color, taste and aroma of wines and deterioration of the nutraceutical properties of wines. White and rosé wines are particularly vulnerable to these changes due to lower amounts of phenolic compounds compared to red wines. The color of young white wine changes from slightly yellow to dark yellow and even to an unacceptable brown. The phenolic compounds found in the largest amounts in white wines are hydroxycinnamic acids and flavanols. Hydroxybenzoic acids and stilbenes are present in low concentrations. The content of phenolic compounds in wines is influenced by the grape variety, growing conditions, wine production technology and the age of the wine. When grapes are crushed, polyphenol oxidase (PPO) is released, which causes the enzymatic oxidation of phenolic compounds to quinones in the presence of oxygen.