Fabrication and characterization of a novel biphasic system based on starch and ethylcellulose as an alternative fat replacer in a model food system

Unlike oleogel and hydrogel, the potential applications of polymer-based bigels as interesting biphasic formulations in foods have not been explored yet. Therefore, novel food-grade bigels were developed using starch and ethylcellulose at different oleogel fractions (25%, 50%, and 75%), and its potential as a fat replacer in a model meat product was assessed for the first time. FTIR and XRD studies suggested that bigels retained the semi-crystalline structures of ethylcellulose that became more orderly at higher oleogel fractions. Electrical conductivity measurements showed the transformation from oleogel-in-hydrogel (25%) to hydrogel-in-oleogel (≥ 50%). Mechanical and viscoelastic properties were mostly affected by the oleogel fraction. Rheological measurements indicated a gel-like behavior even at high temperatures, suggesting good thermal stability. Low-fat burgers were formulated with bigel with 75% oleogel fraction, as the best fat replacer based on mechanical studies. Compared to the control sample with animal fat, all low-fat burgers showed better cooking characteristics, particularly at a higher substitution level. Animal fat replacement up to 50% presented acceptable sensory characteristics. However, lipid oxidation increased by incorporation of bigel.