Valorisation of dietary fibre in oleogel preparation: textural attributes and storage stability

In this work, rice bran wax (4.5% w/w) oleogels were prepared, including different dietary fibres as potential structuring agents. The effect of oil type (sunflower, SFO or extra virgin olive oil, EVO), fibre type (bamboo, citrus or aronia) and concentration (0.5% and 1%) were evaluated based on structural properties and oil binding capacity (OBC). Storage tests under accelerated conditions (illuminated systems at 4 °C and 35 °C for 10 days) were carried out to assess the thermal oxidative stability using peroxide values (PV). No significant texture differences were observed compared to EVO or SFO controls. However, EVO gels without added fibre retained the most oil. The texture of oil/wax is a function of the fibre type. Adding 1% fibre, especially with citrus and aronia EVO and citrus and bamboo fibres in SFO, generally strengthened the gel network. Fibre addition significantly reduced OBC, particularly in EVO systems, where oil loss ranged from 16.8% to 41.4%, compared to the reference gel’s (86.78% of OBC). These results indicate that mechanical reinforcement and oil immobilisation were not directly coupled in the composite wax–fibre networks. From a stability perspective, fibres helped reduce oxidation, especially in SFO samples, with fibre-enriched gels showing about half the PV of controls. Citrus and bamboo fibres were most effective in maintaining low PV levels during accelerated storage.