Strangeness production in pp-bar collision

We study strangeness production reactions in the framework of a Chiral Constituent Quark Model. The model includes the coupling with the SU(3) pseudoscalar meson octet due to the spontaneous chiral symmetry breaking. It also includes QCD perturbative effects through the coupling with the gluon field. In this way the two traditional mechanism of strangeness production, i.e., the kaon exchange and gluon annihilation, are introduce in the same framework. Two meson exchanges are parametrized through the exchange of scalar mesons, namely a sigma and a kappa exchange. The kappa exchange allows a better description of the polarization observables of the pp-bar →ΛΛ-bar production reaction. Other strangeness production reaction in the isospin 1 sector are also studied.