  We present numerical simulations of stellar core-collapse with spherically
symmetric, general relativistic hydrodynamics up to black hole formation. Using
the CoCoNuT code, with a newly developed grey leakage scheme for the neutrino
treatment, we investigate the effects of including pions and \Lambda-hyperons
into the equation of state at high densities and temperatures on the black hole
formation process. Results show non-negligible differences between the models
with reference equation of state without any additional particles and models
with the extended ones. For the latter, the maximum masses supported by the
proto-neutron star are smaller and the collapse to a black hole occurs earlier.
A phase transition to hyperonic matter is observed when the progenitor allows
for a high enough accretion rate onto the proto-neutron star. Rough estimates
of neutrino luminosity from these collapses are given, too.
