The composition, rheological properties and breadmaking behaviour of stored flours

Abstract

Flours milled from English ('weak'), Canadian ('strong') and mixed English and Canadian wheats ('medium') had different rates of lipolysis (weak > medium > strong) during prolonged storage at ambient temperatures (average about 12°C). Lipolysis was more rapid in the medium flour at 25"C, but was very slow in 'control' flours kept at -20°C in an inert atmosphere. Loss of baking quality in stored flours was assessed using the Chorleywood Bread Process (CBP), a long fermentation process (LFP) and the Activated Dough Development process (ADD). The loaf volume changes varied with the flour type and test method, especially depending on whether or not fat was included in the recipes. In tests with fat, the CBP was the most sensitive to deteriorative changes (strong= medium > weak); with the medium and strong flours, loaf volumes were nearly constant for 24 months before decreasing rapidly. Deterioration became apparent more gradually when using LFP and ADD tests with fat. When fat was omitted, short-term improvement (weak > medium > strong) occurred with all three baking methods, but there was subsequent loss of volume. To account for these changes in baking behaviour, it is suggested that the tests differ in their sensitivity to flour type and variations in dough composition, especially to the level of bakery fat, the level of fatty acids (generally deleterious), and to protein changes which were also detectable by rheological tests on stored flour doughs (flour 'maturation' ; generally beneficial).

The effects of pure saturated and unsaturated fatty acids bon breadmaking and on lipid binding, using chorleywood bread process doughs containing a ‘model fat’

“…16 The difference in baking behaviour of doughs containing saturated and unsaturated fatty acids in the CBP is in line with their reported effects on dough and gluten properties, but the similar effects in baking of oleic and linoleic acids were not expected on this basis.…”

“…The relative importance of the different factors which govern the baking performance of flours during storage is discussed in a separate paper. 16 …”

Changes in total fatty acids and individual lipid classes on prolonged storage of wheat flour

“…The Chorleywood Bread Process (CBP) was found to be especially sensitive to storage deterioration of the flours. 3 It is known that cis-unsaturated free fatty acids, when added to fresh flour in a CBP recipe, cause a decrease in loaf volume in proportion to their concentrati~n.~ The effect is apparent only when fat is present in the r e~i p e .~ By contrast simple correlation of the increased level of FFA found in the stored flours, with changing baking quality, is not possible. The most rapid increase in FFA takes place in the initial storage period, when baking quality shows no significant change.3 Further, since FFA are without effect in a CBP recipe containing no fat, changes found to occur when stored flour is baked without fat,3 must be due to some other parameter.…”

“…Loss of baking performance would not be expected during this time, in fact improvement is often reported.l.2 When flour is stored for longer periods however, it shows progressive deterioration in baking performance. [1][2][3] The actual mechanism of deterioration in baking quality remains unproven although it is known that the variation in baking performance, during storage, is dependent on such factors as moisture content,l storage temperature3 and storage atmosphere. 2 Of flour components, the lipid fraction exhibits extensive age-related changes.…”

Glycolipid ranking of bread quality hard wheat breeding stock cultivars by tandem mass spectrometry of total lipid extract

“…In particular, OK Chung related baking loaf volume to the indicative digalactosyldiglyceride (DGDG) content of various wheat cultivars. The wheat polar lipid (or specifically glycolipid) contribution to breadmaking has been the subject of numerous papers prior to or concurrent with the separation of individual contributing glycolipids (Bell et al 1979(Bell et al , 1986Zawistowska et al 1986).…”