Effect of ultrasonication on microstructure, crystallization and rheological properties of mixed Monoglycerides and Tween 20 oleogel networks

The aim of this study was to investigate the impact of ultrasonication on the formation of crystalline network of monoglycerides (MGs) and Tween 20 (Tw20) in a continuous matrix of olive oil. Several analytical methods such as differential scanning calorimetry (DSC), confocal and polarized optical microscopy, rheometry, and infrared spectroscopy (FT-IR) were employed to characterize the ultrasonicated oleogel structures. DSC and FT-IR provided evidence that ultrasonication accelerated the crystallization of the β-polymorph of the monoglycerides. Confocal and optical microscopy revealed that ultrasonication resulted in shorter and thinner β-MGs crystals. The addition of Tw20 to the system led to formation of oil-in-oil emulsion gels with the β-MGs crystals acting as Pickering particles. Rheology showed that ultrasonication induced the formation of stronger but with lower yield stress oleogels. Overall, ultrasonication can modulate the structure of MGs-based crystallized networks, thereby influencing the thermomechanical properties, which could be beneficial for fat substitution in food products.