Phase-change pickering emulsions with solid-core confinement stabilized by tannic acid-functionalized zein nanoparticles for enhanced β-carotene bioaccessibility

Novel phase-change Pickering emulsion microcapsules (PCPEs) were constructed using tannic acid (TA)-modified zein nanoparticles (T-zein) and a lauric acid/stearic acid eutectic (LS) to encapsulate β-carotene. The grafting of TA tuned the wettability of zein nanoparticles, enabling stable emulsification at 50 °C. Subsequent cooling resulted in microcapsules with a T-zein shell and crystalline core (LS), achieving an encapsulation efficiency of 88.15 %. The solidified oil phase restricted molecular migration, while interfacial T-zein provided dual protection, reducing β-carotene degradation under UV irradiation and auto-oxidation by 57.19 % and 67.88 %, respectively, compared with liquid-core emulsions. In vitro digestion studies showed that phase change triggered by physiological temperature enabled controlled release. PCPEs displayed superior gastric stability and resistance to coalescence in the intestine, enhancing the bioaccessibility of β-carotene to 42.57 % (36 % higher than liquid-core emulsions and 298 % of the free control). Overall, this solid-core engineering strategy presents a novel platform for the rational design of emulsion for targeted delivery of lipophilic bioactives.