Fabrication, Characterization, and In Vitro Digestion Behavior of Bigel Loaded with Notoginsenoside Rb1.

Area of Science:

• Food Science and Technology
• Materials Science
• Pharmacology

Background:

• Notoginsenoside Rb1 (Rb1) possesses significant health benefits but suffers from poor oral bioavailability due to gastric degradation and low intestinal permeability.
• Developing effective delivery systems is crucial to harness the therapeutic potential of Rb1.

Purpose of the Study:

• To develop and optimize a food-grade bigel system for encapsulating Rb1.
• To enhance Rb1's stability, control its release, and improve its oral bioavailability.

Main Methods:

• Formulation of oleogels using monoglycerides and soybean oil.
• Preparation of Rb1-loaded binary hydrogels with gellan gum and xanthan gum.
• Emulsification of hydrogels in Tween-80 to create bigels.
• Optimization of hydrogel-to-oleogel ratios.
• Characterization using rheology, confocal microscopy, and differential scanning calorimetry (DSC).
• In vitro digestion tests to assess acid protection and release profiles.

Main Results:

• An optimal bigel formulation (4:6 hydrogel-to-oleogel ratio) was identified with superior structural integrity (peak G' = 290.64 Pa).
• High encapsulation efficiency (99.91%) and homogeneous Rb1 distribution within the hydrogel phase were achieved.
• The bigel demonstrated thermal buffering capacity (endothermic transition at 55 °C) and retained both water and oil.
• Effective protection against gastric degradation ( < 5% Rb1 release) and sustained intestinal release (>90% at 4 h) were confirmed.

Conclusions:

• The developed food-grade bigel system effectively protects Notoginsenoside Rb1 from gastric degradation.
• The bigel system enables controlled and sustained release of Rb1 in the intestine, significantly enhancing its oral delivery potential.
• The system's tunable rheology, thermal stability, and food-grade composition make it highly suitable for applications in functional foods and nutraceuticals.