Structural characterization of levan synthesized by a recombinant levansucrase and its application as yogurt stabilizers

Levan, a class of fructan with complex structure, has been found to have potential as a prebiotic. In this study, the polysaccharide was produced by in vitro catalysis (Cata-lev), structural analysis proved it was levan that possessed a branching degree of about 15% and molecular weight of 2.54 × 106 Da. Furthermore, SEM observation showed that Cata-lev was porous with loose flaky structure. Subsequently, the effects of five Cata-lev concentrations on the fermentation process, texture, nutraceutical, and sensory characteristics of set yogurts were investigated and compared to Fructooligosaccharides (FOS). The addition of Cata-lev could significantly (P < 0.05) increase the water holding capacity (WHC) of fermented yogurt (over 77%). The Cata-lev treatment groups exhibited superior system stability (Zeta and WHC) than FOS. Overall, this study expanded knowledge about levan structure and its potential utilization as a yogurt stabilizer.