Abstract:

Using low field nuclear magnetic resonance (LF-NMR) technique, differential scanning calorimetry (DSC) and
the Avrami model, this research aimed to study the influences of guar gum, soluble soybean polysaccharide and carrageenan
on the water migration, thermodynamic parameters and retrogradation kinetics of fresh noodles during shelf life. The results
showed that after storage for 7 days, the descending order of bound water contents in fresh noodles added with different
polysaccharides was follows: guar gum > soluble soybean polysaccharide > carrageenan > blank (P < 0.05), the decreasing
order of immobilized water contents was as follows: guar gum > carrageenan > soluble soybean polysaccharide > blank
(P < 0.05), and the decreasing order of free water contents was as follows: blank > soluble soybean polysaccharide >
carrageenan > guar gum (P < 0.05). The hydrophilic polysaccharides mainly acted on the bound water attracted to the polar
groups present on the surface of the starch and gluten in fresh noodles. At the same time the bondage of the hydrophilic
polysaccharides on the motility of three kinds of water did not simply obey a linear relationship, and they inhibited the
increases in recrystallization melting onset temperature (T₀), conclusion temperature (T_c) and enthalpy change (ΔH) of
starch retrogradation. Retrogradation kinetics equations for fresh noodles added with different polysaccharides were
Y_blank = 0.732x − 0.946, Y_carrageenan = 0.744x − 1.192, _{Yguar gum} = 0.791x − 1.328, Y_{soluble soybean polysaccharide} = 0.752x − 1.114.

Key words: fresh noodles, low field nuclear magnetic resonance (LF-NMR), differential scanning calorimetry (DSC), moisture migration, retrogradation, hydrophilic polysaccharide