Effect of Metal Cations on the Swelling and Gelatinization Behaviour of Large Wheat Starch Granules

The effect of metal cations on the swelling and gelatinization behaviour of large wheat starch granules has been studied by observing their behaviour in the presence of 24 different chlorides in aqueous solutions. With most salts, increasing concentration results in gelatinization temperatures being first raised, then depressed, and then raised again. Increasing salt concentration may also cause the initial loss of anisotropy to occur at the granule surface instead of at the hilum, and result in an apparent solution of starch rather than swollen granules. The gelatinization phenomena have been classified into three major types, and these are described in detail. It is suggested that both water and partially hydrated salts can act as gelling agents for starch granules, and that the interplay of these two agencies can explain the observed complex relation between gelatinization temperature and salt concentration.