Influence of molecular weight of an anionic marine polysaccharide (sulfated fucan) on the stability and digestibility of multilayer emulsions: Establishment of structure-function relationships

The ability of sulfated fucan to fabricate stable multilayer emulsions has been established in previous studies, but the structure-function relationships governing the formation of these structured emulsions are still poorly understood. In this study, sulfated fucan was extracted from sea cucumber and degraded to different molecular weights (2000-100 kDa) by enzyme hydrolysis. The stiffness and dimensions of the polysaccharides produced decreased as the molecular weight (M-w) was reduced. The impact of the M-w of the fucans on the characteristics of protein-stabilized emulsions was investigated by particle size, zeta-potential, and creaming stability analysis. All the fucans adsorbed to caseinate-coated droplet surfaces from pH 5 to 3 and protected the droplets from aggregation by a combination of steric and electrostatic repulsion. The fucan with the higher M-w saturated the droplet surfaces at a lower concentration. Moreover, multilayer emulsions fabricated from the highest M-w fucan were more resistant to NaCl addition (0-100 mM) and gave better long-term stability. The sulfated fucans with higher molecular weights (2000-600 kDa) could significantly increase the initial digestibility rate of the encapsulated lipid. These results show that the M-w and conformation of sulfated fucans impacts the stability and digestibility of multilayer emulsions, thus providing guidance for the further application of anionic polysaccharides in preparing multilayer emulsions.

Automated summary

This study investigated the impact of molecular weight of sulfated fucans on the characteristics of protein-stabilized emulsions. Results showed that higher molecular weight fucans can enhance the stability and digestibility of multilayer emulsions.