Enhancement of rheological properties and oxidative stability of OSA starch oleogels by chitosan-EGCG conjugates: Influence of chitosan viscosity

The rheology and oxidative stability of oleogels are critical factors impacting their application as solid fat substitutes in the food industry. For this reason, the influence of chitosan-EGCG conjugates on the rheology and oxidative stability of OSA-starch (OS) oleogels was examined. Conjugates were prepared from chitosan ingredients with different viscosities (low viscosity: <200 mPa s and high viscosity: >400 mPa s). Chitosan-EGCG conjugates (HCE) prepared from the high viscosity chitosan provided the highest antioxidant activity. Moreover, oleogel containing a high concentration of HCE (OS-HCE 1 ) had the highest viscoelasticity, thixotropic recovery (91.79 %), and oil-holding capacity (90.95 %), mainly attributed to the formation of more stable protective coatings. The oxidative stability analysis showed that HCE was most effective in delaying lipid oxidation of OS oleogels during storage. Finally, the potential of using the optimized oleogels (OS-HCE 1 ) as fat substitutes in bread products was evaluated by partially or fully substituting fat at levels of 0 %, 25 %, 50 %, 75 %, and 100 %. The results indicated that up to 50 % of commercial margarine could be replaced with oleogel in bread formulations without adversely affecting key quality parameters, including color, shape, texture, and sensory acceptability. In conclusion, this study offers an effective approach for improving both the structural and oxidative stability of OSA starch-based oleogels and provides valuable guidance for the formulation of healthier lipid systems in bakery applications.