Plant-Based Bigels for Functional Delivery: Advances in Structural Design and Stabilization Strategies

As the increasing demand for clean-label, plant-based, and functional food systems, bigels, an innovative biphasic structured system composed of both hydrogels and oleogels, have emerged as promising research focus for delivering functional ingredients in the food, pharmaceutical, and cosmetic fields. Plant-based bigels, formulated from edible biopolymers and vegetable oils, represent a sustainable and regulatory-compliant delivery platform. This review critically reviews the recent advances in the structural design and stabilization of plant-based bigels, with an emphasis on the regulation of phase behavior and interfacial interactions. Advanced strategies, including stimuli-responsive gelation, Pickering interfaces, and semi-interpenetrating networks, are explored to improve stability and enable targeted gastrointestinal release. Applications in the delivery of polyphenols, omega-3 fatty acids, lipophilic vitamins, and probiotics are highlighted, underscoring the relationship between structural construction and delivery performance. Furthermore, current challenges and potential solutions concerning stability enhancement, bioavailability improvement, and industrial scalability are outlined. Future research directions are proposed to address existing gaps and to further exploit the potential of plant-based bigels for functional compound delivery.