Optimization of Coriander Seed Oil Oleogel and Evaluation of Its Technological Performance in Dark Chocolate...

Due to the high saturated fat content, increasing cost, and supply instability of cocoa butter (CB), the development of structured lipid systems with improved nutritional profiles and suitable technological functionality has received increasing attention. This study aimed to optimize a coriander seed oil-based oleogel (COG) using a D-optimal mixture design and evaluate its potential as a structured lipid phase for dark chocolate formulation. The effects of coriander seed oil, monoglycerides, candelilla wax, xanthan gum, and polyglycerol polyricinoleate (PGPR) on the physicochemical, rheological, and mechanical properties of the oleogel were investigated. The optimized COG formulation exhibited a maximum crystallization temperature of 30.159 °C, enhanced viscoelastic characteristics, and a stable three-dimensional lipid network. The optimized oleogel retained substantial amounts of bioactive compounds, including α-tocopherol, phenolic compounds, flavonoids, and linalool, together with antioxidant activity, and showed a lower accumulation of primary oxidation products during storage than the non-structured oil. Dark chocolate prepared with the optimized oleogel (COG-Ch) was evaluated in comparison with cocoa butter-based chocolate (CB-Ch) in terms of thermal behavior, rheological properties, texture, and storage-related whitening changes. Although COG-Ch showed comparable onset and maximum melting temperatures and a lower increase in whiteness index during storage at 35 °C, significant differences remained in melting enthalpy, hardness, and several rheological parameters compared with CB-Ch. These differences reflect the distinct lipid organization and crystallization behavior of the oleogel system. Therefore, the developed coriander seed oil oleogel should be considered a promising structured lipid phase for chocolate applications rather than a complete functional equivalent of cocoa butter. Further investigations involving sensory evaluation, crystal polymorphism analysis, microstructural characterization, and comprehensive oxidative stability assessment are required to determine its broader applicability in chocolate manufacturing.