STORAGE OF PACKAGED WHITE BREAD .3. EFFECTS OF SOUR DOUGH AND ADDITION OF ACIDS ON BREAD CHARACTERISTICS

Effects of three ferments, sponge (S), refrigerated sponge (RS) and spontaneous sour dough (SS), with and without addition of acids (citric acid, lactic acid and acetic acid) on the characteristics and shelf-life of white bread was studied. Bread samples ranked widely in pH (5.71-3.47) and total tritatable acid (TTA) (3.90-15.67 ml NaOH). The SS, having the lowest pH and highest TTA and lactic/acetic ratio gave the bread with the highest volume, good crumb grain and the lowest rate of staling during storage. Further acidification of 20% SS sample by addition of acids caused lower volume, coarser crumb grain and less typical flavour as well as faster staling. The use of 20% SS delayed the growth of mold, extending bread shelf-life twofold with respect to that of straight dough bread (D). Addition of organic acids to 20% SS formulation increased shelf-life up to more than 30 days, depending on the acid and its proportion: citric acid 0. 12% < citric plus lactic 0.25% < citric plus lactic 0.5% = citric plus acetic 0.125%. Fresh S and D breads showed lower enthalpy values (DELTA-H(g)) than RS and SS breads, increasing in the latter with percentage of SS added. Addition of organic acids to 20% SS bread formula decreased DELTA-H(g) of fresh bread. During storage DELTA-H(g) values of all samples-increased sharply in the first five days. The 20% SS bread underwent the smallest change and the D and S breads the highest ones.