Abstract
The effects of polyunsaturated phospholipids on changes in the thermal and physical properties of starch systems during mixing, baking and storage were studied. In the presence of phospholipids (PLs) or polyunsaturated fatty acid-containing PLs (PUFA-PLs), the viscoelastic properties of starch dough, such as stress, modulus of elasticity and viscosity coefficient were decreased, and the gelatinization enthalpy (Δhg) of dough also decreased slightly, but the starch-lipid complexes (Δhs-l) of dough and bread increased distinctly. Twenty-one days after its storage, the retrogradation rate (k) that was estimated by the change of re-gelatinization enthalpy (Δht) of starch containing PLs or PUFA-PLs, was slowed by a factor of 1.98 or 3.28 for dough; and 1.60 or 2.07 for bread, respectively, when compared with that of the control. The changes in retrogradation value of starch in bread seemed to correlate with the retrogradation value of starch in dough in differential scanning calorimetric data (r2=0.93). These changes in thermal and physical properties of dough and bread appeared to be caused by the formation of complexes between starch and the PLs.
