Preparation, characterization, and application of a novel chestnut starch-based bigel as a fat substitute in bread

This study developed a novel self-assembled bigel by combining a chestnut starch (CS) hydrogel with a γ-oryzanol/β-sitosterol (γ-ORY/β-SIT) oleogel. The influence of the hydrogel to oleogel ratio on the macro and micro structures, mechanical properties and thermal stability of the bigels was examined, and its potential as a healthier solid fat substitute was further explored. The results indicated that as the proportion of hydrogel increased (10 %-50 %), all bigels maintained a consistent semi-solid structure without any phase separation. When the hydrogel ratio reached 20 %, the bigel exhibited an oil-holding capacity of 99.35 %, the strongest freeze-thaw stability, and the highest melting temperature (58.12 ± 0.18 °C), demonstrating excellent gel properties and stability. Therefore, we selected the bigel with a 20 % hydrogel ratio, applied it in bread production with varying proportions of solid fat substitutes. The texture and sensory evaluation of the bread were analyzed. The findings indicated that substituting 50 % of the butter in the bread with bigels didn't significantly change the product's appearance and properties (chamber area: 29.79 %; sensory score: 8.27 ± 0.12). This research proposed the creation of a novel CS bigel and provided new theoretical support for its use as a substitute for solid fat.