Utilization of safflower seed by-product protein for gluten-free muffin production: A physicochemical and rheological perspective

Abstract

This study investigates the potential of producing gluten-free muffins using protein isolate (SFP) derived from a by-product of cold-pressed safflower seed oil. The textural and physicochemical properties of muffins were evaluated alongside the steady shear, dynamic, and 3-ITT rheological characteristics of muffin batters containing varying levels of SFP and gluten-free and gluten-containing control batters. Steady shear rheological analysis showed that all batters exhibited shear-thinning behavior, with viscosity decreasing as shear rate increased. The consistency index (K) ranged from 29.67 to 173.21 Pa·sn, increasing with higher SFP ratios, while the flow behavior index (n) decreased from 0.64 to 0.44, indicating enhanced pseudoplasticity. Frequency sweep tests revealed crossover points between storage modulus (G′) and loss modulus (G″) for SFP3, SFP6, and C2 samples at higher frequencies. In contrast, SFP9, SFP12, and C1 showed G′ consistently exceeding G″, reflecting stronger viscoelastic properties. 3-ITT tests confirmed that all batters displayed thixotropic behavior with full structural recovery. Higher SFP ratio muffins showed comparable pore structure to control samples and notable improvements in hardness and specific volume. These results indicate that SFP is a sustainable and valuable ingredient that enhances the rheological properties and overall quality of gluten-free muffins, offering an innovative approach to developing gluten-free products.