  The implications of the latest data pertaining to \bar u-\bar d asymmetry and
the spin polarization functions on the contributions of singlet Goldstone boson
\eta' within \chiCQM with configuration mixing for explaining the ``proton spin
problem'' have been investigated. It is found that the present data favors
smaller values of the coupling of singlet Goldstone Boson \eta' as compared to
the corresponding contributions from \pi, K and \eta Goldstone bosons. It seems
that a small non-zero value of the coupling of \eta' (\zeta \neq 0) is
preferred over \zeta=0 phenomenologically.
