High internal phase Pickering emulsion by Spanish mackerel proteins-procyanidins: Application for stabilizing astaxanthin and surimi

High internal phase Pickering emulsions (HIPPEs) stabilized by food-grade proteins have attracted much attention. In this study, Spanish mackerel protein (SMP)-procyanidin (PC) hybrid nanoparticles (SPHPs) were prepared through electrostatic interactions and hydrogen bonding as an emulsifier for HIPPEs. Transmission electron microscopy (TEM) showed that, unlike the spherical SMPs, the SPHPs had a cross-linked structure with rough surface. The particle size of HIPPE droplets decreased with increasing SPHP concentration. Photographs and magnetic resonance imaging (MRI) showed that the HIPPEs stabilized by SPHPs had a stable gel structure and the oil protons were evenly distributed when the oil fraction of HIPPEs was 85%. Low-field nuclear magnetic resonance (LF-NMR) transverse relaxation showed that the water state in HIPPEs stabilized by SPHPs was mainly immobilized and showed good stability after 4 weeks of storage. Rheological analysis showed that the HIPPEs had good viscoelasticity and thixotropy. Simulated digestion experiments showed that the HIPPEs improved the bioaccessibility of astaxanthin. The application of HIPPEs in surimi products shows that HIPPEs in surimi had a high adhesion rate (47.89%) and good cooking stability. HIPPEs stabilized by SPHPs could achieve efficient delivery of astaxanthin and had the potential to be applied to functional surimi products in the form of simple adhesion.