Quality characteristics and antioxidant properties of cookies fortified with brewer’s spent grain powder

This study investigated the effects of adding brewer’s spent grain (BSG) powder at varying concentrations (10-40%) on the quality characteristics and antioxidant activity of cookies. Physicochemical analysis revealed that as BSG content increased, cookies’ spread factor, leavening rate, moisture content, pH, lightness, and yellowness significantly decreased. Conversely, hardness, ash content, protein content, acidity, soluble solids, redness, and browning index showed marked increases. The total polyphenol and flavonoid contents in cookies increased proportionally with BSG addition, reaching 4.26-fold and 4.05-fold higher values than those of the control, respectively. Correspondingly, antioxidant activities, as measured by ABTS radical scavenging and reducing power assays, were significantly enhanced with high BSG concentrations, whereas DPPH radical scavenging showed a modest increase. These results suggest that BSG powder can serve as a valuable functional ingredient in cookie formulations, improving antioxidant properties and affecting the physical and sensory attributes. This study highlights the potential of upcycling food industry byproducts into health-promoting baked goods, contributing to sustainable food processing and functional food development.