The effects of soy on freezable bread dough: A magnetic resonance study

Hygroscopic soy ingredients were hypothesised to slow the rate of water migration in unleavened bread dough during frozen storage. Thawed soy (18% dry weight) and wheat dough samples were assessed using non-destructive nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) for up to 8 wks frozen storage time. MRI suggested a spatially homogeneous, net increase in proton mobility with frozen storage and, with solution state proton NMR, distinct “free” and “bound” states were discerned. T2 relaxation times of the majority proton population suggested increased mobility with frozen storage time, and statistical difference from the fresh sample was seen later for the soy samples than the wheat samples. As seen by 13C-solid state NMR, the crystallinity of the starch was not affected by either soy addition or frozen storage. In conclusion, addition of soy to bakery products led to slightly enhanced preservation of “fresh” characteristics of the dough during frozen storage.

► Soy reduced the rate of change in properties of bread dough during frozen storage.
► Using NMR, a net increase in water mobility was observed during frozen storage.
► Macroscale water migration was not observed in dough during frozen storage.