  Properties of cold nuclear matter are studied within a generalized
Nambu-Jona-Lasinio model formulated on the level of constituent nucleons. The
model parameters are chosen to reproduce simultaneously the observed nucleon
and pion masses in vacuum as well as saturation properties of nuclear matter.
The strongest constraints on these parameters are given by the empirical values
of the nucleon effective mass and compression modulus at nuclear saturation
density. A preferable value of the cut-off momentum, determining density of
active quasinucleon states in the Dirac sea, is estimated to about 400 MeV/c.
With the most reasonable choice of model parameters we have found a first order
phase transition of the liquid-gas type at subsaturation densities and the
gradual restoration of chiral symmetry at about 3 times the saturation density.
Fluctuations of the scalar condensate around its mean-field value are estimated
and shown to be large in the vicinity of chiral transition.
