FIRMING OF STARCH GELS AND AMYLOPECTIN RETROGRADATION AS RELATED TO DEXTRIN PRODUCTION BY ALPHA-AMYLASE

The effect of dextrins produced by a-amylase on the firming and amylop ectin retrogradation of wheat starch gels was studied. Different gel s amples were prepared and included several ingredients, for example, al pha-amylase, vital gluten and glucoamylase. Amylopectin retrogradation , gel firming and the dextrin profile were analysed throughout a 5-day storage period. Both processes, i.e. firming and starch retrogradatio n, increased with time, and were not affected by the incorporation of gluten into the mixture. The well-known effect of alpha-amylase to ret ard bread crumb firming was also found to be relevant to starch gels. From the results obtained in this work, it seems that this anti-firmin g effect is not due to modifications of the starch but to dextrins pro duced by starch hydrolysis, since the effect did not occur when dextri ns were removed by glucoamylase.