Reconstruction of fat crystal organization by a phytosterol/γ-oryzanol bigel: Linking structural evolution in blended...

The crystal organization of plastic fats plays an important role in determining the structural and functional properties of bakery systems. Commercial vegetable butter (VB) is widely used in bakery applications because its crystalline network contributes to dough processing and baked product quality. Although bigels have emerged as promising structured fats with reduced saturated fat content, how bigel incorporation changes the crystal organization of an existing commercial fat matrix and how these changes are reflected in dough and cookie properties remain poorly understood. In this study, butter cookies were used as a model bakery system to investigate changes in the crystal organization of VB after incorporation of a phytosterol/γ-oryzanol-sodium alginate bigel and their association with dough architecture and cookie quality. Crystal morphology, polymorphism, solid fat content (SFC), and thermal behavior of the blended fat systems were characterized, followed by analyses of dough microstructure, rheological properties, texture, water distribution, and cookie quality. Bigel incorporation progressively reduced crystal aggregation and SFC while altering the polymorphic characteristics and thermal behavior of the blended fat systems. Both β- and β'-type structures remained detectable in the BG-VB blends. Dough viscoelasticity and hardness decreased with increasing BG content, whereas water mobility was reduced in association with the hydrogel phase. At the product level, cookie spread ratio decreased from 4.31 to 3.65-3.90 for BG-containing cookies, breaking force increased from 25.63 to 26-30.97 N for BG-containing cookies, and baking loss remained unchanged. Oil migration remained below 1% after complete replacement of VB, while acceptable sensory quality was maintained. The results show that changes in fat crystal organization, SFC and water distribution were associated with changes in dough architecture and cookie properties in the phytosterol/γ-oryzanol-sodium alginate bigel/VB system. These findings provide insights into the relationship between structured fat organization, dough properties and cookie quality, and may support the development of alternative fat systems for bakery applications.