Effects on Physicochemical, Nutritional, and Quality Attributes of Fortified Vegan Muffins Incorporated with Hempseed as an Alternative Protein Source

This study investigated the potential of hempseed protein isolate (HPI) as a protein fortifier and wheat flour substitute in vegan muffins. HPI was incorporated at 0% (CON), 10% (HP10), 20% (HP20), and 30% (HP30) substitution levels, and muffins were evaluated for physicochemical, functional, and sensory properties. Protein content significantly increased from 9.61% (CON) to 19.40% (HP30), while baking loss decreased from 21.33% to 19.77%, reflecting HPI’s superior water-holding capacity. Texture analysis showed hardness decreased from 179.72 g/cm² (CON) to 137.73 g/cm² (HP30), resulting in softer muffins with higher chewiness. This correlated with a more aerated crumb structure and smoother surface at higher HPI levels, indicating improved structural integrity. Rheological analysis revealed increased batter viscosity and shear-thinning behavior with HPI fortification. FTIR analysis exhibited redshifts in the Amide I and Amide II bands, suggesting enhanced protein–protein interactions and hydrogen bonding in fortified HPI muffins. Antioxidant activity increased significantly, with ABTS radical scavenging values rising from 32.66% (CON) to 46.28% (HP30), attributed to the bioactive peptides and phenolic compounds (144.67 mg GAE/g) in HPI. However, in vitro protein digestibility (IVPD) decreased from 66.08% to 42.63% due to protein–starch–lipid interactions inhibiting hydrolysis. Sensory evaluation showed no significant differences in aroma, taste, mouthfeel, or overall acceptability, with scores between 4.83 and 5.33 among all samples. These results demonstrate that HPI incorporation of up to 30% significantly enhances the nutritional profile, antioxidant activity, and textural properties of vegan muffins while maintaining overall sensory quality, supporting HPI’s potential as a sustainable protein fortifier in plant-based bakery products.