The effect of mono‐diglycerides on the mechanical properties, microstructure, and physical stability of an edible rice bran wax–gelatin biphasic gel system

Abstract Bigels are prepared by homogenization of an organogel and hydrogel. Bigels can offer improved properties such as enhanced physical stability and the ability to interact with both hydrophilic and lipophilic moieties and substances when compared to other gelled systems due to its semi‐solid internal phase, biphasic nature, and supramolecular interactions between components. The objective of this study was to determine the effect of mono‐diglycerides (MDG) on the supramolecular structure and interactions, physical stability, and mechanical properties of a rice bran wax–gelatin bigels. The organogel‐to‐hydrogel (OG:HG) ratios tested were 60:40, 70:30, and 80:20 with MDG incorporated at four concentrations (0.5%, 1%, 2%, 3% [w/w]). Bigels were analyzed using nuclear magnetic resonance spectroscopy, confocal scanning laser microscopy (CSLM), Fourier transform infrared spectroscopy (FTIR), texture analysis, and liquid binding capacity studies. The results showed that MDG have a dual effect on the structural organization and stability of the systems; they act as emulsifiers and/or crystallization modifiers. CSLM and FTIR showed that the addition of MDG had the greatest effect on the microstructure of the 60:40 OG:HG ratio, where MDG concentrations 0.5% and 1% (w/w) exhibited a reduction in the size of the oleogel regions while concentrations 2% and 3% (w/w) showed a phase inversion. MDG addition resulted in a gradual decrease in bigel hardness, but an enhancement of physical stability.