Abstract:

Response surface methodology (RSM) was used to optimize the modification process for corn starch by enzymatic
hydrolysis combined with extrusion. Main process parameters including high temperature resistant α-amylase dosage,
extrusion temperature and corn starch concentration were studied. The sugar composition, microstructure, crystallinity
and thermodynamic properties of corn starch before and after modification was examined by high performance liquid
chromatography (HPLC), scanning electron microscope, X-ray diffraction technique and differential scanning calorimetry. The
results showed that when 40 U/g of high temperature-resistant α-amylase was added, the extrusion was performed at 140 ℃
and corn starch concentration was 70%, the maximum DE value of 19.55% was achieved. HPLC analysis showed that the
sugar components of the extruded product were separated effectively with a ratio of glucose to maltose to maltotriose to
maltotetraose to maltopentaose of 1.0:3.4:7.5:6.0:1.8. The microstructure of the modified starch particles exhibited holes on
the surface and the degree of crystallinity decreased.

Key words: extrusion combined with enzymatic hydrolysis, corn starch, modification process, high performance liquid chromatography