Sargassum filipendula flour improves composition, digestibility, and antioxidant activity of gluten-free biscuits

Sargassum filipendula (SF), a brown seaweed, is abundant along the Brazilian coast; however, it has not yet been applied in the food industry. This study investigates the incorporation of SF flour ingredient in gluten-free biscuits. Two gluten-free cookie formulations were developed: one containing 100% rice flour and 0% SF (F0), and another containing 99% rice flour and 1% SF (F1), while keeping the other ingredients constant. FO and F1 were then comparatively analyzed for their technological properties, and in vitro digestibility, and antioxidant activity were determined in SF, F0 and F1. The F1 biscuit had significantly ( p ≤ 0.05) higher ash and moisture content, lower textural hardness, but. Color analysis indicated a darker and more yellowish tone in F1, associated with natural seaweed pigments.In vitro digestion revealed gradual and sustained protein hydrolysis in SF, reaching 100% at 240 min, while F0 and F1 reached a plateau during intestinal digestion, and F0 and F1 showed the same estimated Glycemic Index (eGI) (62.0). Antioxidant activity, measured by the ORAC assay, reached 13,993.93 μM TE/g at the end of SF intestinal digestion, and was consistently higher in F1 compared to F0 throughout digestion. Overall, SF demonstrated potential ingredients in gluten-free biscuits, because only 1% of substitution produced a softness and brown biscuit with better digestibility of protein and antioxidant capacity. • S. filipendula seaweed flour has high ash content and antioxidant capacity. • Replacing 1% of rice flour with S. filipendula decreased gluten-free biscuit hardness. • Biscuits with algae showed greater antioxidant activity in vitro. • Among the cookies with and without algae, those with algae had lower hardness and a brownish color. • The study highlights the potential application of S. filipendula as a functional ingredient in gluten-free biscuits. • S. filipendula may be an ingredient to impart functional properties in baked goods.