pH-responsive Pickering emulsions synergistically stabilized by chitin nanocrystals and shellac nanoparticles for astaxanthin delivery

This study aims to utilize the synergistic effect between shellac nanoparticles (SNPs) and chitin nanocrystals (ChNCs) to construct Pickering emulsion (PE) with adjustable structures and properties for loading and delivering astaxanthin. The viscoelastic properties and stability of SNPs-ChNCs co-stabilized PE demonstrated markedly enhanced performance compared to systems stabilized individually by SNPs or ChNCs, particularly at a 5:1 SNPs/ChNCs ratio. Furthermore, the PE demonstrated notable pH responsiveness and salt ion resistance. Encapsulation performance evaluation revealed the SNPs/ChNCs co-stabilized system achieved enhanced payload parameters for astaxanthin. The S5C1 formulation demonstrated optimal encapsulation performance, achieving 92.1 % encapsulation efficiency (EE) with a loading capacity (LC) of 1.05 % under optimized conditions. Furthermore, the retention rate of astaxanthin exceeded 90 % after 21 days of storage and 8 h of UV irradiation. More importantly, the S5C1 PE showed a high free fatty acid (FFA) release rate and bioaccessibility of astaxanthin after simulated gastrointestinal digestion. This study provides a novel strategy for constructing pH-responsive PE and delivery system for functional active substances.