  Using QCD sum rules, we compute the diagonal meson-baryon couplings, $\pi
NN$, $\eta NN$, $\pi \Xi\Xi$, $\eta \Xi\Xi$, $\pi \Sigma \Sigma$ and $\eta
\Sigma \Sigma$, from the baryon-baryon correlation function with a meson,
$i\int d^4x e^{iq\cdot x} < 0| T J_B(x) {\bar J}_B(0)|M(p)>$. The calculations
are performed to leading order in $p_\mu$ by considering the two separate Dirac
structures, $i \gamma_5 \gamma_\mu p^\mu$ and $\gamma_5 \sigma_{\mu \nu} {q^\mu
p^\nu}$ separately. We first improve the previous sum rule calculations on
these Dirac structures for the $\pi NN$ coupling by including three-particle
pion wave functions of twist 4 and then extend the formalism to calculate the
other couplings, $\eta NN$, $\pi \Xi\Xi$, $\eta \Xi\Xi$, $\pi \Sigma \Sigma$
and $\eta \Sigma \Sigma$. In the SU(3) symmetric limit, we identify the terms
responsible for the $F/D$ ratio in the OPE by matching the obtained couplings
with their SU(3) relations. Depending on the Dirac structure considered, we
find different identifications for the $F/D$ ratio. The couplings including the
SU(3) breaking effects are also discussed within our approach.
