Construction and Performance Evaluation of a Bifidobacterium Delivery System Based on TBP-SA Pickering Emulsion Gels

Abstract

An emulsion gel (EG-B) was fabricated through in situ calcium crosslinking of Pickering emulsions stabilized by tartary buckwheat protein–sodium alginate (TBP-SA) nanocomplexes for the encapsulation and delivery of Bifidobacterium longum. Control samples, including free bacteria (Free-B), Pickering emulsions (PE-B), and oil-free hydrogels (HG-B), were used to assess encapsulation efficiency, microstructure, rheological properties, thermal stability, dilution stability, gastrointestinal resistance, storage stability, and colonic adhesion of EG-B. The EG-B exhibited a dual structure comprising a compact Pickering interfacial membrane and a continuous calcium alginate gel network with solid-like rheology (G′>>G″) and viscosity of approximately 100 Pa·s, achieving 92.66% encapsulation efficiency. Viable counts exceeded 6 log CFU/g after pasteurization (72 °C, 15 s) and reached 6.12 log CFU/g post-simulated gastrointestinal digestion, significantly surpassing those of PE-B (5.12 log CFU/g) and HG-B (4.45 log CFU/g). Furthermore, EG-B displayed the highest viable retention during 14-day storage at 4 °C and 25 °C, along with a greater colonic adhesion efficiency (55.64%) compared to PE-B (47.09%) and HG-B (44.65%). The combination of interfacial stabilization and gel network formation provided by the TBP-SA complex presents a straightforward, food-grade strategy for probiotic delivery.