Abstract:

Polysaccharides were prepared from corn bran by the steps of supercritical CO2 fluid extraction for removing fat, alkaline protease hydrolysis for removing protein and α-amylase hydrolysis for removing starch. Then the oligomerization of corn bran polysaccharides was conducted through extrusion. According to degree of polymerization (DP) and molecular weight (MW) measured with viscosimetry, the oligomerization conditions of corn bran polysaccharides were optimized through orthogonal test. The results showed that the optimal conditions are as follows : material to liquid ratio 1:1.4, extrusion temperature 175 ℃, particle size of material 0.147 mm and feed speed of material 10 kg/h. Under the above conditions, the DP of corn bran polysaccharides drops from 894 to 66, and its MW reduces from 144828 to 10612.

Key words: oligomerization, corn bran, polysaccharide, extrusion