  We discuss a three-flavor Nambu--Jona-Lasinio (NJL) type quantum field
theoretical approach to the quark matter equation of state (EoS) with scalar
diquark condensate, isoscalar vector mean field and Kobayashi-Maskawa-'t Hooft
(KMT) determinant interaction. While often the diquark and vector meson
couplings are considered as free parameters, we will fix them here to their
values according to the Fierz transformation of a one-gluon exchange
interaction. In order to estimate the effect of a possible change in the vacuum
pressure of the gluon sector at finite baryon density we exploit a recent
modification of the Polyakov-loop NJL (mPNJL) model which introduces a
parametric density dependence of the Polyakov-loop potential also at T=0, thus
being relevant for compact star physics. We use a Dirac-Brueckner-Hartree-Fock
(DBHF) EoS for the hadronic matter phase and discuss results for mass-radius
relationships following from a solution of the TOV equations for such a hybrid
EoS in the context of observational constraints from selected objects.
