Effect of polyaccharides and proteins on refrigerated dough quality
Abstract
Refrigerated dough is considered one of the most popular dough products in the
food industry. Consumers appreciate the convenience, storage stability, and good
organoleptic properties of refrigerated dough products. However, in practice, the quality of
refrigerated dough can deteriorate during the storage as a result of liquid formation in
dough, which is called "dough syruping". The objectives of this study were (1)
characterization of the structural properties of dough components that affect dough
syruping; (2) identification of rheological changes that occur during refrigeration, and as
they relate to arabinoxylans (AX), starch and protein solubility.
The data showed that AX solubilization and degradation occurred simultaneously
with dough syruping. Nuclear magnetic resonance (NMR) spectroscopy analysis and the
viscosity analysis of AX aqueous solution confirmed that AX solubilization and
degradation resulted in the increase of low molecular weight fraction and the decrease of
high molecular weight fraction in water extractable AX (WEAX). The pasting properties
and thermal properties of starch changed during the storage: peak viscosity decreased up to
23.1 % compared to flour samples during 34 days refrigerated storage. Variation in starch
granular morphology was detected. These results showed that physicochemical properties
of starch changed during refrigerated storage. The rheological properties of dough changed
dramatically during refrigerated storage, which may have significant impacts on endproduct
quality. Both, the elastic modulus (G') and viscous modulus (G") decreased. Dough exhibited the major decrease on the moduli on day 3 and day 16. By comparing the
viscoelastic properties of dough samples on day O and day 16, 50% decrease on the elastic
modulus and a roughly 30% decrease in the loss modulus were observed. Changes in the
protein fractions of dough samples were related to their rheological properties. Therefore,
the physicochemical properties of polysaccharides and proteins appear to be directly
correlated to dough syruping, which may result in the diminishment of rheological and
organoleptic properties of refrigerated doughs.