A novel bigel containing rice bran sterol as both a structuring agent and a delivered bioactive component, along with...

A functional solid fat replacer was developed by combining a rice bran sterol (RBS)-structured oleogel (O) with a soy protein isolate-corn starch (SPI-CS) hydrogel (H). A 20% RBS level produced a mechanically robust oleogel and delivered an adequate load of bioactive RBS. The phase fraction of O/H has a significant impact on the properties of the bigel. Analysis of the microstructure showed that increase in the oleogel fraction induced a shift in phase continuity, with a highly interconnected, bicontinuous-like morphology formed at the 50:50 formulation (BG5). BG5 exhibited butter-comparable spreadability and textural profile analysis profile, along with high oil-binding capacity (98%) and enhanced thermal mechanical stability. In vitro digestion showed that BG5 had the highest FFA release rate of 57.93% and achieved the highest bioaccessibility of RBS (triterpenoid alcohols) with value of 36.04%, defined as the percentage of triterpenoid alcohols recovered in the micellar phase relative to the initial loading, representing a significant enhancement compared to the observed 17.77%-28.19% in other formulations. In cookie preparation, BG5 enabled up to 75% butter replacement while preserving crispness-related textural attributes. Overall, RBS-based bigels provide a practical plant-based platform for structuring healthier fats and improving the micellar bioaccessibility of lipophilic bioactives.