Pasting and thermal properties of waxy corn starch modified by 1,4-α-glucan branching enzyme

Waxy corn starch was modified with the 1,4-alpha-glucan branching enzyme (GBE) from Geobacillus thermoglucosidans STBO2. Incubating waxy corn starch with GBE increased the number of alpha-1,6 branch points and reduced the average chain length. Enzymatic modification also decreased the breakdown and setback values of Brabender viscosity curves, indicating that the modified starch had higher paste stability. Pre-heating the starch at 65 degrees C for 30 min before incubation with GBE could promote enzymatic modification of starch. Linear regression was used to describe the relationships between starch structure and its pasting and thermal properties. The setback value showed a negative linear correlation with the alpha-1,6 branch point content (R-2 = 0.9824) and a positive linear correlation with the average chain length (R-2 = 0.8954). Meanwhile, the gelatinization enthalpy was also linearly correlated to the alpha-1,6 branch point content (R-2 = 0.9326) and the average chain length (R-2 = 0.8567). These insights provide a useful reference for food processors. (C) 2017 Elsevier B.V. All rights reserved.