Structure-function relationships between the primary structural properties and multilayer emulsion-fabricating function of an anionic polysaccharide (sulfated fucan)

In this study, four sulfated fucans different in primary structures (sulfation patterns and the presence of branch) were obtained from different sea cucumbers and hydrolyzed to a similar molecular weight level (1100 kDa) by using a heterologously overexpressed fucanase. The influence of the primary structure of sulfated fucan on the multilayer emulsion-fabricating function was investigated. Results showed that the sulfation patterns had limited influence on the multilayer emulsion-fabricating function of sulfated fucan. All examined sulfated fucans could electrostatically adsorb to the surfaces of caseinate-coated droplets from pH 5 to 3, regardless of the primary structures. The sulfated fucans with a linear structure saturated the droplet surfaces at a lower concentration compared with the sulfated fucan with a branched structure. However, the multilayer emulsions fabricated from branched sulfated fucan were more resistant to NaCl stress (100 mM) than the emulsions fabricated from linear fucan. Furthermore, the fastest digestion rate and highest digestion extent were found in the multilayer emulsion fabricated by branched fucan. These results established the structure-function relationships between the primary structures and multilayer emulsion-fabricating function of sulfated fucan.