THE ROLE OF MALTODEXTRINS IN THE STALING OF BREAD

Recent reports suggest that dextrins produced by anti-staling alpha-am ylases are directly involved in retarding the staling process. We repo rt experiments that test this hypothesis using a new method of dextrin extraction at 90 degrees C in the presence of papain. Various dextrin s were added to standard bread and extracted under a variety of condit ions. No change in staling rate was observed, but, in most cases, ther e was little difference between the level of dextrins extracted from b aked loaves and that from the control leaves, confirming that added de xtrins are hydrolysed by native flour amylases. Adding a bacterial alp ha-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 presen ce of dextrins in a specific size class. It appears that dextrins pres ent in an amylase-treated loaf are symptomatic of a modification to th e starch that retards staling, but are not the direct cause of the ant i-staling effect. (C) 1997 Academic Press Limited.