Effect of electron beam irradiation on physicochemical properties of corn starch and improvement of enzymatic saccharification of corn starch at high concentration (45%)

Abstract

Cornstarch was irradiated under different doses of electron beam radiation (0–5.4 kGy), and the physicochemical properties of starch were analyzed. The dextrose equivalent (DE) values, which is a representative indicator of saccharification in the sugar production process, was measured after the EBI pre‐treated cornstarch at high concentration (45%, wt/wt) was hydrolyzed by thermostable α‐amylase and glucoamylase. The reducing sugar content of the cornstarch markedly increased with increasing irradiation dose. In addition, reduced transmittance, flexural vibration of chemical bond, the viscosity, and the relative crystallinity decreased with increasing irradiation dose. Scanning electron microscope (SEM) showed that the penetrating pinholes and pits were observed on the surface of irradiated cornstarch granules. After being hydrolyzed by thermostable α‐amylase and glucoamylase, slurry of cornstarch EBI pre‐treated at dose of 4.32 and 5.4 kGy exhibited the low viscosity values and high dextrose equivalent (DE) values. The resulting low viscosity values and high dextrose equivalent (DE) values slurry from EBI pre‐treated cornstarch have potential for use in syrup industry. Practical Applications The slurry made from EBI pre‐treated cornstarch at the concentration of 45% (wt/wt)exhibited a rather low viscosity values and high dextrose equivalent (DE) values compared with that of the slurry (45% wt/wt)made from the non‐EBI pre‐treated cornstarch. Therefore, the use of starch modified by electron beam irradiation treatment could lead to reduce corn syrup processing costs. Corn syrup is an important raw material of bakery industry. The reduction of its production cost is of great significance for stabilizing the market price of bakery food and promoting the coordinated development of bakery industry.