The ProHand project investigated the economic and technical feasibility of converting plant‑based by‑products into value‑added food ingredients for regional bakeries and snack manufacturers. The study focused on soy okara, oat, coconut, and almond residues, as well as emerging sources such as spinach, pea, and algae. The research was carried out from 2021 to 2023 in collaboration with the Fraunhofer Institute UMSICHT, the food‑processing company Berief Food GmbH, and the bakery‑confectionery Hecker. Funding was provided by the German Federal Ministry for Economic Affairs and Energy (BMEL) and supported by the Food‑Processing Initiative e.V. (FPI). Key partners contributed raw material supply, laboratory analysis, and pilot‑scale processing, while the Fraunhofer team supplied process engineering and economic assessment.

Technically, the project evaluated three processing routes: fresh, frozen, and powdered. Fresh residues require rapid cooling and immediate use, which limits scalability due to logistical constraints. Frozen residues eliminate the need for immediate processing and reduce enzymatic activity, but introduce freezing energy costs and require block‑level thawing. The powdered route, involving drying after mechanical separation, proved most attractive for bakery integration. By drying to a 95 % dry‑matter product, the resulting powder has a low water activity, enabling room‑temperature storage and extended shelf life. The drying step also reduces volume and transport costs, offsetting the energy input.

Energy consumption for drying was quantified for each residue type. For soy okara at 21 % dry‑matter, the energy requirement was 12 kWh per kilogram of dry powder. Coconut and oat residues required 9 kWh/kg and 6 kWh/kg, respectively. These figures were combined with electricity costs (12 c/kWh for soy, 9 c/kWh for coconut, 6 c/kWh for oat), personnel, depreciation over five years, and packaging to calculate total drying costs. For soy okara, the overall cost per kilogram of 95 % dry powder was approximately €0.30, including raw‑material and logistics expenses. The study also demonstrated that the dried protein powders could be incorporated into bread, pastries, snack bars, spreads, and pastes without compromising sensory quality or nutritional value. Pilot trials at Hecker’s bakery confirmed that the powders could replace up to 20 % of conventional wheat flour or serve as a protein supplement in vegan products, improving protein content while maintaining dough rheology.

The project’s transfer activities included presentations at the FPI “Alternative Protein Sources” workshop, the Anuga FoodTec conference, and the NRW Climate Bakery meeting, where the new ingredients were showcased to industry stakeholders. Feedback indicated strong acceptance of almond and coconut residue powders, while soy okara and oat powders required further product development. The study also identified potential applications in muesli bars, crispbreads, and healthy snack formulations, expanding the market reach of the by‑products.

Overall, ProHand demonstrated that plant‑based residues can be efficiently processed into stable, high‑protein powders suitable for regional food production. The technical data provide a clear cost framework, and the collaborative network ensures a pathway from laboratory to commercial bakery lines, supporting sustainable ingredient sourcing and circular economy goals.