Transforming the food system towards more sustainable and plant-based diets requires more than replacing animal-based products. It also means rethinking how raw materials are processed, how side streams are valorised and how nutritional quality, taste and functionality can be improved at the ingredient level.

Within the Sustain-a-bite consortium, VTT is contributing to this transition by exploring how germination, solid-state fermentation and lactic acid fermentation for biopreservation can enhance the qualities of plant-based ingredients. The work focuses on three key raw materials: barley, faba bean and tomato side stream.

The latest results show how these processing methods can help create ingredients that are not only more sustainable, but also nutritionally richer, easier to process and more appealing for consumers.

“By improving ingredients before they become final products, Sustain-a-bite is helping plant-based innovation move closer to foods that are healthier, more functional and more enjoyable to consume.”

Germination as a tool to improve nutritional quality

One of VTT’s main research lines has focused on the germination of barley and faba bean. Germination trials were carried out under different conditions, including variations in temperature, steeping time, mineral addition and drying programmes.

The results confirmed that germination can significantly improve the nutritional and techno-functional profile of plant-based raw materials. In barley, folate levels more than doubled, representing an important nutritional improvement. At the same time, gamma-aminobutyric acid, known as GABA, increased significantly in both barley and faba bean.

Germination also increased sugars and free amino acids, which can support better flavour development and improve fermentability. This is particularly relevant for the creation of plant-based food and beverage products where taste, texture and processing performance are essential for consumer acceptance.

Among the main benefits observed, germination helped to:

• Increase nutritional value, including higher folate levels in barley.
• Improve fermentability, thanks to higher sugars and free amino acids.
• Support mineral availability, by reducing phytic acid and increasing iron, zinc and calcium content through mineral steeping.
• Improve protein digestibility, through higher protein hydrolysis and nitrogen extractability.
• Enhance processability, with lower viscosity in barley upon heating, which may be useful for beverage applications.

Another important outcome was the reduction of phytic acid by up to 20%. Since phytic acid can limit mineral absorption, its reduction helps improve the potential bioavailability of minerals in the final ingredient. In addition, steeping in mineral solutions successfully increased the content of iron, zinc and calcium, further improving the nutritional profile of the raw materials.

Sensory results were also encouraging. The flavour profile of germinated ingredients was described as pleasantly sweet, and the presence of rootlets did not negatively affect sensory quality. Overall, the effects of germination were more pronounced in barley than in faba bean, but both raw materials showed valuable potential for further development.

Solid-state fermentation opens new possibilities for plant proteins

VTT has also investigated solid-state fermentation as a way to improve the functionality and nutritional value of faba bean. Trials were performed using single fungal cultures and cocultures combining Aspergillus, Rhizopus and lactic acid bacteria.

The results showed that all coculture combinations grew well, confirming the suitability of faba bean as a matrix for fermentation. The final pH varied widely, from 4.5 to 7, which opens the possibility of developing different ingredient and product profiles depending on the desired application.

A key finding was the significant increase in total extractability, suggesting improved availability of compounds after fermentation. In addition, phytic acid degradation increased by up to 45%, reinforcing the potential of fermentation to reduce antinutritional factors and support better mineral availability.

The different microbial combinations also produced distinct aroma profiles. Importantly, all aroma profiles were considered acceptable, showing that solid-state fermentation can create new sensory opportunities without compromising product quality.

In practical terms, solid-state fermentation can support plant-based ingredient development by helping to:

• Reduce antinutritional compounds, including phytic acid.
• Improve extractability and ingredient performance.
• Create different product profiles through pH variation.
• Develop acceptable aroma profiles using different microbial combinations.
• Open new applications for faba bean in plant-based foods.

These findings point to solid-state fermentation as a promising tool for plant protein processing, particularly in applications where improved digestibility, flavour and functionality are needed.

Tomato pomace fermentation for natural biopreservation

Another important area of work has focused on the fermentation of tomato pomace, a side stream that can be valorised as a plant-based ingredient. VTT screened nine lactic acid bacterial strains in tomato pomace, both in raw and wet-milled forms.

All tested lactic acid bacteria were able to grow in the tomato pomace matrix. The pH decreased clearly during fermentation, especially in wet-milled tomato pomace, indicating effective fermentation.

The results also showed that lactic acid bacteria inhibited the growth of aerobic bacteria. Some strains were able to suppress indigenous yeasts and moulds as well, supporting the potential of fermentation as a method for natural biopreservation.

This approach offers a promising pathway for creating low-waste, microbiologically stable plant-based ingredients. By improving shelf life and safety while making use of side streams, fermentation can contribute both to product quality and to more sustainable resource use.

“Turning side streams into stable, functional ingredients is one of the clearest examples of how food innovation can reduce waste while creating new value.”

Moving towards food prototypes

The next stage of VTT’s work within Sustain-a-bite focuses on transferring these results into practical applications. Over the coming months, the team will continue finalising analyses of germinated and fermented ingredients, delivering selected ingredients for food prototyping and scaling up the most promising microbial and ingredient combinations.

Prototype development will focus on two main product directions:

• A plant-based meat alternative, using solid-state fermentation with tomato pomace, barley and faba bean.
• A fermented smoothie, developed with lactic acid and propionic acid bacterial cultures using germinated and non-germinated barley and faba bean.

These prototypes will help assess how enriched ingredients can contribute to improved texture, nutrition, flavour and consumer acceptance in real food applications.

They also represent an important step in translating scientific findings into tangible food concepts that can be tested, refined and potentially scaled.

From results to future food applications

VTT’s results show that germination and fermentation are powerful tools for improving plant-based ingredients before they reach the final product stage. These processes can help increase nutritional value, reduce antinutritional compounds, improve mineral and vitamin availability, support better digestibility and create more favourable sensory properties.

Just as importantly, they can help valorise side streams such as tomato pomace, turning underused materials into stable, functional ingredients with real food application potential.

At a glance, the latest results highlight three key messages:

• Better nutrition: germination and fermentation can increase valuable compounds while reducing antinutrients.
• Better functionality: improved extractability, viscosity and digestibility can support food processing.
• Better sustainability: side streams can be transformed into useful ingredients instead of being wasted.

As Sustain-a-bite moves towards prototype development, these enriched ingredients will provide the foundation for new food concepts, including plant-based meat alternatives and fermented smoothies. This marks an important step towards food solutions that are not only more sustainable, but also nutritious, functional and appealing for consumers.