The role of maltodextrins in the staling of bread

Recent reports suggest that dextrins produced by anti-staling alpha-amylases are directly involved in retarding the staling process. We report experiments that test this hypothesis using a new method of dextrin extraction at 90 degrees C in the presence of papain. Various dextrins were added to standard bread and extracted under a variety of conditions. No change in staling rate was observed, but, in most cases, there was little difference between the level of dextrins extracted from baked loaves and that from the control leaves, confirming that added dextrins are hydrolysed by native flour amylases. Adding a bacterial alpha-amylase of intermediate temperature stability (Novamyl) or a fungal glucoamylase of intermediate temperature stability (GA300N) or alpha-amylase plus glucoamylase to the dough, produced leaves with different dextrin profiles. Measured staling rates did not relate to the presence of dextrins in a specific size class. It appears that dextrins present in an amylase-treated loaf are symptomatic of a modification to the starch that retards staling, but are not the direct cause of the anti-staling effect. (C) 1997 Academic Press Limited.