Small deformation dynamic oscillation was used to investigate the stru
ctural behaviour of conformationally dissimilar maltodextrin and milk
protein macro-molecules in a mixture, with the view of identifying the
state of phase separation and the pattern of solvent distribution bet
ween the two constituent phases. The enthalpic nature of the maltodext
rin network produced a sigmoidal transition in the development of stor
age modulus (G') during cooling and substantial thermal hysteresis upo
n heating of the gel. By contrast, the entropically-driven build up of
structure in milk protein samples yielded linear and overlapping cool
ing and heating scans of G' with networks reverting into solutions at
relatively low temperatures. These differences in the viscoelastic fun
ctions of the two polymers in combination with theoretical analysis (i
sostress-isostrain models, Kerner equation) have documented the reinfo
rcing effect of strong and spherical maltodextrin inclusions on the we
aker and continuous milk protein phase. However, at concentrations of
maltodextrin beyond the phase inversion point, the binary assembly com
prises a strong and continuous maltodextrin network surrounding the we
aker milk protein inclusions. Finally, the sharp change in the pattern
of water partition between the two polymeric components, as a result
of phase inversion in the system, was rationalised on the basis of kin
etically-influenced co-gels comprising phase separated networks which
are trapped away from the state of thermodynamic equilibrium. Copyrigh
t (C) 1996 Published by Elsevier Science Ltd