The Sustainable Beverages (SusBev) project aims to use and ferment agricultural residues and side streams from viticulture and other regional agricultural processes to produce health-focused beverages, targeting adults who prefer to stay sober. In their first project, researchers are working with wine experts to use the leaves of new grape varieties adapted to climate change to make wine-like drinks.

The project, which launched earlier this year, is a sub-project of the “Bioeconomy Innovation Space in Metropolitan Regions” (BioBall) — and is one of four initiatives in the focus of the BMBF’s National Research Strategy Bioeconomy 2030.

BRAIN Biotech, Tropical Viticulture Consultants, Zukunftsweine GmbH and Provadis Hochschule are participating in the SusBev project. BRAIN Biotech is responsible for the selecion and optimization of suitable microorganisms (starter cultures) as well as the basic establishment of the bioprocess on a laboratory scale.

We speak with Dr. Alice Kleber, senior project manager of R&D, microbial strain development at BRAIN Biotech, who discusses how the project came about.

“Warm and humid weather encourages the growth of fungi on plants and fruit, leading to crop failure — which is why new fungus-resistant grape varieties are increasingly being planted.”

Unlike traditional grape varieties, these new varieties must be established by winemakers in both cultivation and winemaking, she tells Food Ingredients First. “Consumers have to accept new varieties and different taste profiles, i.e., the products have to be well received in the market. These new varieties, which require fewer pesticides, also open up new product opportunities.”

As in the BRAIN Biotech project, the leaves are suitable for consumption and can be used as a food by-product, adds Kleber.

Commenting on how this contributes to a circular economy, she says: “By utilizing waste and side streams from viticulture for food production, the carbon stored in them is used as food, rather than being released directly as unused CO2 through composting, as is currently the case.”

“This increase in CO2 efficiency adds to the already favorable carbon footprint of piwi grape varieties compared to conventional grape varieties, as they require less spraying and significantly fewer chemicals (especially fungicides) during cultivation.”

Utilizing agricultural residues
According to Kleber, the rapidly growing world population and climate change require efficient use of agricultural land while minimizing negative environmental impacts such as carbon footprint or use of chemicals.

“In addition to increasing yields and plant health, the focus should be on utilizing agricultural residues and side streams that have not yet been used for food.”

BRAIN Biotech is implementing this in its “Vine Leaf Fermentation Project.”

“Here, agricultural residues and side streams from viticulture and other regional agricultural processes are used and refined in fermentation processes to produce healthy and tasty food,” Kleber explains.

“The initial aim is to produce non-alcoholic drinks as an alternative to wine. The core of the project — as with any fermentative application development — is the selecion of the best functioning, food-safe microorganisms (especially yeasts, fungi and bacteria or their combination) and the adaptation of the fermentation conditions to the substrate vine leaves.”

Grape varieties
Biotechnologists from BRAIN Biotech are working with regional winegrowers to develop an aromatic, low-calorie and non-alcoholic drink from residual and by-products of viticulture.

“This involves using the vine leaves and shoots left over from pruning, which are not currently recycled. So-called fungus-resistant piwi grape varieties are particularly suitable for this, as their leaves have an attractive aroma and these varieties also require less treatment with pesticides. This means that these parts of the plant can be consumed safely,” notes Kleber.

Researchers are using the leaves of new grape varieties adapted to climate change to make non-alcoholic beverages. The vine leaves and shoots of these varieties, which have not yet been used as a raw material, are suitable because they have an attractive, varietal flavor (like the berries from which wine is made).

In addition, their resistance to fungal attack means that the plants require less pesticide treatment, making them safe for consumption.

The leaves are first macerated and extracted in aqueous form. The resulting wine leaf infusion is then fermented to create the actual product with an attractive taste, she details. “A special type of fermentation is used to achieve typical wine characteristics such as flavor complexity and mouthfeel without producing alcohol.”

Preliminary work has shown that grape leaves from different piwi varieties yield infusions with very different flavor profiles. This variety of flavors provides an ideal basis for investigating to what extent high-quality non-alcoholic beverages can be produced — also with the aim of accompanying food, but also in the area of “adult social drinking,” Kleber tells us.

Future plans
Kleber reveals that the current project is not limited to grape leaves but also examines the transferability to other agricultural products as well as residual and side streams, such as pomace and pulp from fruit and vegetable processing or leaves from other plant species.

“Grape pomace is of particular interest here, as the berry skins and seeds it contains already contain fully developed flavors that can be used to produce flavorful beverages,” she states.

“We intend to apply the knowledge gained in this research project on the fermentative upgrading of agricultural side streams, on suitable microbial resources (food-grade organisms) and on product prototypes to new substrates. In this way, we will be able to evaluate and process additional sidestreams more quickly in the future,” outlines Kleber.

“This will shorten our development time for the customers and help them to bring their products to market more quickly.”