Tailoring Rheological and Structural Properties of Bigels for Solid Fat Replacement: Influence of Gelator Type
摘要
Conventional solid fats play a key role in food structure and texture but raise health and sustainability concerns due to their high saturated and trans-fat content and environmental impact. Bigels offer a promising alternative by combining hydrogel and oleogel networks to create healthier lipid systems without compromising functionality. This study investigates how different gelators affect rheological, textural, microstructural and thermal properties of bigels with 80:20 oleogel-to-hydrogel ratio, formulated using a lipid-based low molecular weight gelator glycerin monostearate (GMS), or a non-lipidic polymeric gelator, ethylcellulose (EC), in the oleogel, in combination with thermo-reversible hydrocolloids sodium alginate (SA) or low acyl gellan gum (GG) in the hydrogel. Rheological analysis using Ostwald-de Waele power law model showed that viscosity and shear-thinning behavior were mainly influenced by oleogelator, while bigel strength was influenced by both phases. Among all formulations, the GMS–SA bigel exhibited the highest resistance to deformation, with a storage modulus (G′) of approximately 105 Pa. GMS bigels melted between 45 and 60 ℃, EC bigels remained stable during temperature changes. Furthermore, the oleogelator significantly influenced particle size and distribution: GMS-containing bigels showed larger and more broadly distributed particles (131.17–163.08 μm), whereas EC-containing bigels exhibited smaller and more uniform particles (51.75–94.08 μm). These findings provide key insights into the structural and functional properties of bigels, reinforcing their potential as solid fat replacers in plant-based high-fat food applications such as meat analogues, bakery products, and dairy alternatives.
Graphical Abstract