Upcycling strawberry pomace into functional cookies: Dietary fiber enrichment, antioxidant delivery, and bioaccessibility after simulated digestion

Abstract

Strawberry pomace, an underutilized residue from juice processing, provides abundant dietary fiber and polyphenols, which may contribute to health promotion. The objective of this study was to valorize this residue by producing strawberry pomace flour (SPF) through freeze-drying and milling, and incorporating it into cookies as a functional ingredient. SPF was characterized for its fiber content, total phenolic content (TPC), and antioxidant capacity (ABTS). For cookies development, wheat flour was partially replaced with SPF (15 and 30%), and cookies were evaluated for composition, technological properties (color, texture, and geometrical parameters), TPC, and antioxidant activity during in vitro gastrointestinal digestion. SPF exhibited high levels of fiber (43.1 ± 0.4 g/100 g), TPC (3,100 ± 100 mg GAE/100 g), and antioxidant activity (9,900 ± 100 mg TE/100 g). Enriched cookies showed approximately twofold and fourfold increases in dietary fiber at 15 and 30% substitution, respectively, compared to the control cookie. A 30 g serving of cookies with 30% substitution provided 12% of the recommended daily intake of fiber. Polyphenol content and antioxidant activity were also enhanced, with values approximately doubled at the highest substitution level, and remained bioaccessible after digestion. Technological quality was maintained, supporting SPF as a sustainable resource to enhance the nutritional profile of cookies.