Starch gelatinization causes Starch to quickly break down to Amylopectin and Amylose, which are both long-chain carbohydrates.
Then Alpha-Amylase, By acting at random locations along the starch chain,
break down the long-chain carbohydrates, ultimately yielding maltotriose and maltose from Amylose,
AND maltose, glucose and "limit dextrin" from Amylopectin.
Because it can act anywhere on the substrate, Alph-Amylase tends to be faster-acting than Beta-amylase.
Beta Amylase takes Starch apart by breaking off two glucose units(maltose) at a time, from the Ends of the Starch Chain.
Source: http://en.wikipedia.org/wiki/Amylase" onclick="window.open(this.href);return false;