Co-encapsulation of curcumin and catechin in a grass pea protein/beeswax bigel: Enhancing rheological properties, encapsulation efficiency, and bioaccessibility.

Curcumin (CUR) and catechin (CAT) offer significant bioactivity, but their co-delivery is challenging due to their opposing solubilities, instability, and poor bioaccessibility. Therefore, to co-encapsulate CUR and CAT, a novel bigel preparation method (Type I) was developed, differing from the conventional approaches that involve mixing pre-formed gels. In this novel method, a grass pea protein isolate (GPPI) dispersion and beeswax/sunflower oil were homogenized at specific ratios (30:70, 50:50, and 70:30) and then incubated at 37 °C to induce enzymatic cross-linking. Type I bigels showed markedly improved structural and functional properties, including complete oil-binding capacity (100%), higher elastic modulus (3000 Pa), consistency index (375 Pa·sⁿ), and hardness (2.38 N), as well as enhanced encapsulation efficiency for both bioactives. During in vitro digestion, Type I systems delayed gastric release (CAT: 36%; CUR: 14% at 2 h) and promoted rapid intestinal release (CAT: 78%; CUR: 84% at 4 h), resulting in improved bioaccessibility (CUR: 66-76.3%; CAT: 35-43.8%). Notably, while the 70:30 HG-to-OG ratio provided optimal mechanical strength, the 50:50 ratio achieved superior controlled release and antioxidant activity. Therefore, this study introduces an energy-efficient, scalable strategy for bioactive delivery, enabling the sustainable production of innovative functional foods.