Mechanism of gas cell stabilization in breadmaking. II. The secondary liquid lamellae

The study for the first time demonstrates that flour lipids at their natural levels do not affect dough rheology as measured by bubble inflation, thus indicating the presence of liquid lamellae as an independent secondary gas cell stabilizing mechanism in bread dough. The liquid lamellae, stabilized by adsorbed surface active compounds, plays its role during the later proving and early baking stage, when discontinuities occur in the gluten–starch matrix surrounding gas bubbles. To study this secondary stabilizing mechanism, different lipid fractions were added incrementally to the defatted flours. No effects were observed on the rheological properties of the dough. However, large effects on the loaf volume were measured. The additives used were the total flour lipid and its polar and non-polar fractions and the fatty acids palmitic, linoleic and myristic. Polar lipids and palmitic acid had positive or little effect on loaf volume, respectively. Non-polar lipid, linoleic and myristic acids had negative effects on loaf volume. The different effects of the lipid fractions are thought to be related to the type of monolayer that is formed. Polar lipid and palmitic acid form condensed monolayers at the air/water interface whereas non-polar lipid, linoleic and myristic acids form expanded monolayers.