Tailoring the oral sensation and digestive behavior of konjac glucomannan-gelatin binary hydrogel based bigel: Effects of composition and ratio

In the food industry, there is a growing demand for bigels that offer both adaptable oral sensations and versatile delivery properties. Herein, we developed bigels using a binary hydrogel of konjac glucomannan (KGM) and gelatin (G) combined with a stearic acid oleogel. We closely examined how the oleogel/hydrogel volume ratio (φ) and the KGM/G mass ratio (γ) influenced various characteristics of the bigels, including their microstructure, texture, rheological properties, thermal-sensitivity, oral tribology, digestive stability, and nutraceutical delivery efficiency. A noteworthy observation was the structural evolution of the bigels with increasing φ values: transitioning from oleogel-in-hydrogel to a bicontinuous structure, and eventually to hydrogel-in-oleogel. Lower γ values yielded a softer, thermally-responsive bigel, whereas higher γ values imparted enhanced viscosity, stickiness, and spreadability to the bigel. Oral tribology assessments demonstrated that φ primarily influenced the friction sensations at lower chewing intensities. In contrast, γ played a significant role in augmenting oral friction perceptions during more intense chewing. Additionally, φ dictated the controlled release and bioaccessibility of curcumin, while γ determined digestive stability. This study provides valuable insights, emphasizing that through meticulous selection and adjustment of the hydrogel matrix composition, bigels can be custom-fabricated to achieve specific oral sensations and regulated digestive behaviors.