Oleogels derived from modified starch-gelatin-tannic acid aerogel templates: Fabrication, characterization and application

There has been growing interest in the development of viscoelastic oleogels based on edible polysaccharides and/ or proteins as potential replacements for trans and/or saturated fatty acids in food products. In this study, oleogels were prepared from crosslinked oxidized starch (OS)-gelatin (GE)-tannic acid (TA) composite aerogel templates. The rheological properties, oxidative stability, and potential application of these oleogels as fat replacers in bread were then characterized. FTIR spectroscopy analysis of the aerogels showed that the OS and GE were held together by covalent cross-links, while the TA was attached to the aerogel network through hydrogen bonds. The presence of the covalent cross-links increased the porosity and mechanical strength of the composite aerogels, leading to better oil structuring properties. The results showed that the oil-holding capacity and elastic modulus of the oleogel formed by the OS-TA-GE ternary composite aerogel (OTG(2)) at an aerogel-to-oil ratio (w/ w) of 1:7 reached 74.05 % and 54.53 kPa, respectively, which were much higher than those of the OS-TA binary aerogel. In addition, the presence of tannic acid in the oleogels improved significantly (p < 0.05) their oxidative stability. The potential of using the optimized oleogels as replacements for margarine in baked bread was also examined. Bread containing the oleogels had a similar texture and odor as bread containing margarine. In conclusion, the novel oleogels fabricated in this study have considerable potential as margarine or butter substitutes for utilization in bakery products and other foods.