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 (phi) and the KGM/G mass ratio (gamma) 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 phi values: transitioning from oleogel-in-hydrogel to a bicontinuous structure, and eventually to hydrogel-in-oleogel. Lower gamma values yielded a softer, thermally-responsive bigel, whereas higher gamma values imparted enhanced viscosity, stickiness, and spreadability to the bigel. Oral tribology assessments demonstrated that phi primarily influenced the friction sensations at lower chewing intensities. In contrast, gamma played a significant role in augmenting oral friction perceptions during more intense chewing. Additionally, phi dictated the controlled release and bioaccessibility of curcumin, while gamma 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.