Sustainable Management of Fruit By-Products Through Design Thinking: Development of an Innovative Food Product

Sustainable development and the circular economy have become key challenges in the modern food sector, calling for innovative solutions that reduce waste and promote the efficient use of resources. The aim of this study was to develop a functional food product by utilizing by-products from chokeberry processing, thereby contributing to circularity in food systems. The integration of design thinking with fermentation of chokeberry pomace is presented in this study as an approach to developing value-added food ingredients. Qualitative consumer research (focus group interviews, n = 36) identified preferences and expectations regarding functional foods containing by-products. Conducted by an interdisciplinary team, the project followed five stages, involving both qualitative and quantitative research. Liquid surface fermentation was performed using Aspergillus niger , selected for its proven ability to enhance the antioxidant capacity and polyphenol content of plant matrices. The optimal process was 2-day fermentation under controlled pH conditions with glucose supplementation, which significantly enhanced the quality and nutritional value of the final product. Antioxidant activity (ABTS, FRAP, CUPRAC assays), total polyphenols, anthocyanins, and proanthocyanidins were determined, showing significant increases compared to non-fermented controls. The outcome was the development of a dried, fermented chokeberry pomace product that meets consumer expectations and fulfils sustainability goals through waste reduction and innovative reuse of fruit processing by-products.