Effect of octenylsuccinic anhydride modification on β-amylolysis of starch

The effects of octenylsuccinic anhydride (OSA) modification of waxy maize and sorghum starches on subsequent β-amylolysis are examined. Hydrolysis with β-amylase is a method by which OSA starches may be structurally modified for industrial purposes. The hydrolysis of both granular and gelatinised forms of both starches follows first-order kinetics regardless of the OSA used as a percent of starch mass (0-24%). The highest hydrolysis rate coefficients for granular starches are at modification with 6% OSA/starch. The largest molecular sizes of β-amylase hydrolysed OSA-modified gelatinised starches are found at modification with 24% OSA/starch. The results suggest that octenylsuccinyl groups have an action-blocking effect on β-amylolysis of gelatinised starch, but the effect of semi-crystalline granular structure is more pronounced than that of OSA modification. Hence β-amylolysis can be used under appropriate conditions to modify the structure of gelatinised OSA-modified starches.