Enhancing the storage stability and shelf-life of plant-based Pickering emulsions through emulgel formation

Plant-based food Pickering emulsions which are rich in nutrients have recently attracted wide attention due to their plant origin and new functionalities that can be introduced. However, the storage stability and shelf-life are significant concerns for plant-based food. In this study, we report enhanced stability of oat flour-based Pickering emulsions (PEs) through emulgel formation by thermal treatment with minimal processing. The PEs stabilised using oat particles with and without mild-chemical treatment were prepared and heated at varying temperatures (50, 65, 75, and 90 °C) and for different durations (0.5, 1, 5 and 15 min). Subsequently, they were characterised based on particle size and microstructural analysis. The PEs subjected to mild chemical treatment exhibited enhanced thermal stability compared to the control, showing smaller droplet sizes and no coalescence, even at high temperatures. The treatment at higher temperatures (75 °C and 90 °C) afforded the formation of emulsion gels or ‘emulgels’ as evidenced by the results on flow behaviour, dynamical rheology, and texture. The heat-treated PEs displayed a gel-like structure and desirable characteristics (viscoelastic behaviour, firm gel-like texture). In particular, the PEs based on mild-chemically treated oat particles exhibited exceptional properties upon heat treatment at 90 °C for 15 min, displaying a strong 3D gel-like network structure and high storage modulus value.