Effect of Vanillin and Chitin Particles on the Chitosan-Based Oleogels Produced by the Emulsion-Templated Method

This study presents the first assessment of the combined effect of vanillin and chitin particles on the rheological, oil retention, textural, and oxidative properties of chitosan-based oleogels formulated with olive oil. Oleogels were prepared with and without vanillin; in the latter case, the vanillin-to-chitosan ratio was kept constant (1.3), while chitin concentrations (% <i>w</i>/<i>w</i>) were variable (0.0, 0.5, 1.5, and 2.0). Fresh oleogels and those stored for 15 days were characterized. Results demonstrated that vanillin promotes the formation of compact viscoelastic networks, enhances the elastic modulus by approximately 1.3 times, improves oil binding capacity from 75.1% to 89.2%, and significantly improves oxidative stability by minimizing lipid degradation. In contrast, the influence of chitin was dependent on its content and the presence of vanillin. At intermediate content, chitin positively affected cohesiveness and elasticity, particularly in vanillin-free systems. However, in formulations containing vanillin, even low chitin concentration disrupted the gel network, leading to a decrease in hardness, low oil retention, and a higher oxidation degree. Significant correlations between hardness and elastic modulus, oil binding capacity, adhesiveness, and damping factor were obtained for fresh and stored oleogels.