Enzymatic production and characterization of manno-oligosaccharides from Gleditsia sinensis galactomannan gum

Enzymatic hydrolysis of Gleditsia sinensis gum was performed to produce manno-oligosaccharides having functional applications as dietary fiber and prebiotics. The optimum hydrolysis conditions, including enzyme loading, temperature and time, from response surface methodology were 8.1 U/g, 57.4 °C and 34.1 h, respectively. The yield of DP 1–5 oligosaccharides was 75.9% (29.1 g/L). The Michaelis–Menten kinetics and molecular weight distribution were determined. The obtained oligosaccharides were further separated by HPLC and SEC, and the galactose distribution of G. sinensis gum was elucidated. Results indicated that G. sinensis gum has potential to produce value-added oligosaccharides in food industries.

► Gleditsia sinensis gum was hydrolyzed by β-mannanase to produce oligosaccharides.
► The hydrolysis conditions were optimized by response surface methodology.
► 75.9% (29.1 g/L) oligosaccharides were yielded from the galactomannan gum.
► Enzyme kinetics and changes of MWD and apparent viscosity were determined.
► Structural characterization was conducted for the resulting oligosaccharides.