Fabrication of beeswax/plant sterol ester-gelatin/whey protein isolate bigels with dual gelation effects as substitutes for traditional solid fats

Abstract

This study developed bigels as substitutes for solid fats, utilizing beeswax/plant sterol esters oleogel and gelatin/whey protein isolates hydrogel. Analysis focused on the effects of varying hydrogel to oleogel ratios on their microstructure, textural properties, and stability. As the oleogel content surpassed 50 wt%, a shift from O/W to W/O type was observed. Bigels with 60 wt%-80 wt% oleogel content exhibit higher hardness, ranging from 298.53 ± 30.33g to 376.55 ± 30.43g. Those with 50 wt% oleogel content show a peak shear strength of 8067.18 ± 17.41 g.sec. The melting temperatures of the bigels ranged from 52.218 to 109.423 °C, higher than the single oleogel at 45.934 °C. X-ray diffraction revealed a polycrystalline structure with α, β, and β′ polymorphs in the W/O bigels, indicating a more organized structure with increased oleogel. During the sensory evaluation, bigels with 60 wt% oleogel content (8.22 ± 0.22) closely resembled butter (8.58 ± 0.14), achieving the highest overall acceptability. After 30 days at room temperature (25 °C), the bigels with 60 wt% oleogel content exhibited excellent water retention (83.78 ± 3.70%) and oil retention (80.05 ± 1.93%), promising for the design of sustainable, low-calorie fat alternatives.