Densely packed matrices as rate determining features in starch hydrolysis

• Rate limiting step in starch digestion controls levels of amylase resistance.
• Local starch molecular density major rate-controlling structural feature.
• High density achieved by (re-)crystallization or dense amorphous packing.

To aid in the design of starch-containing foods with slow and/or incomplete digestion in the upper gastrointestinal tract, the starch structural factors which control the rate of action of alpha-amylase are reviewed. It is concluded that local starch molecular density has the major influence on amylase digestion kinetics, and that density sufficient to either limit enzyme binding and/or slow down catalysis can be achieved by either crystallization or dense amorphous packing.