Comparative analysis of nutritional, rheological, and sensory attributes of biscuits enriched with white and black chia seed powders: Evaluation under Egyptian cultivation conditions

This study investigated the impact of fortifying wheat flour biscuits with white (CACH-W) and black (CACH-B) chia seed powders at substitution levels of 0 % (control), 5 %, 10 %, and 15 % to develop functional biscuits with improved nutritional and sensory qualities. At all substitution levels, the chemical composition, rheological behavior, and sensory properties of the biscuits were evaluated. Black chia seed powder (CACH-B) contained higher levels of protein, fiber, minerals, phenolics, and antioxidants compared with white chia (CACH-W) and wheat flour. Both chia types exhibited favorable fatty acid profiles, with ω6/ω3 ratios close to 1:2. Chia incorporation enhanced the protein, fiber, and mineral contents of the biscuits, with CACH-B formulations providing greater nutritional improvement but showing slight sensory decline at higher substitution levels. Physical properties such as weight and volume decreased with chia addition, while pasting behavior showed increased viscosity due to chia mucilage. Incorporation of up to 15 % chia powder maintained acceptable product quality, highlighting its potential for health-oriented bakery applications. Overall, fortification with chia seed powder substantially improves the nutritional profile of biscuits, with minimal compromise on sensory acceptability, suggesting that moderate substitution (5–10 %) offers an optimal balance. This research contributes to the development of sustainable, functional bakery products that align with current trends in food innovation and consumer health.