A SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF IODINE BINDING-CAPACITY FOR STARCH AND ITS COMPONENTS

A spectrophotometric method for the determination of iodine binding capacity (IBC) for amylose, amylopectin and starch on a microscale is developed. It is based on the observation that free iodine (I3-) can be determined fairly accurately by recording the absorbance at 286 nm. By using a constant volume titration method, bound iodine is calculated by subtracting the free iodine from the total iodine. A plot of free iodine vs bound iodine shows an inflection, which on extrapolation gives the bound iodine. The IBC values obtained by this method are in good agreement with those obtained by conventional potentiometric and amperometric methods.