Development of chitosan based oleogel using emulsion template approach: Characterization and application as fat-replacer in cookies

The present study aimed to enhance the fat quality of bakery products by incorporating an oleogel enriched with unsaturated fatty acids and nutraceuticals. The efficacy of cross-linking chitosan with vanillin was evaluated using an emulsion-template technique. This approach utilized a blend of rice bran oil and soybean oil fortified with β-sitosterol, which partially replaced conventional shortening in cookie formulations. FTIR spectroscopy confirmed that cross-linking occurred due to the formation of a Schiff base through the reaction between the aldehyde group of vanillin and the amino group of chitosan. Rheological characterization revealed that the oleogel C2P2.5 (2.5 % β-sitosterol in the oil phase) exhibited greater strength than C2P5 (5 % β-sitosterol in the oil phase). Additionally, C2P2.5 demonstrated higher structural recovery than C2P5, indicating superior re-stabilization ability following mechanical deformation. The microscopical analysis showed a firmly packed structure of a continuous 3D network due to intermolecular cross-linking holding the oil. CLSM revealed phase reversal during emulsion formation due to an increase in β-sitosterol concentration in the oil phase interfering with cross-linking. As a result, the strength of oleogel C2P5 was reduced. The fatty acid profile of the oleogel was similar to that of the stock oil, confirming the effectiveness of the structuring technique. These oleogels were used to replace 25 % and 50 % of conventional shortening in cookies, which were subsequently characterized using texture analysis, FTIR spectroscopy, and SEM. With a 50 % replacement, trans-fat content in the cookies was reduced by half, demonstrating that oleogels offer a healthier alternative to conventional bakery shortenings. Collectively, oleogels enriched with unsaturated fatty acids and nutraceuticals, combined with chitosan cross-linking, provide a promising alternative to conventional shortening in bakery products, improving fat quality and reducing trans-fat content.