[en] A Hoelder inequality analysis of the QCD Laplace sum rule which probes the non-strange (nnbar) components of the I=(0,1) (light-quark) scalar mesons supports the methodological consistency of an effective continuum contribution from instanton effects. This revised formulation enhances the magnitude of the instanton contributions which split the degeneracy between the I=0 and I=1 channels. Despite this enhanced isospin splitting effect, analysis of the Laplace and finite-energy sum rules seems to preclude identification of either a₀(980) or a light broad σ-resonance as states with predominant nnbar components, in which case their dominant components could then be meson-meson (ππ or KKbar), multiquark, or glueball states. This apparent decoupling of σ≡f₀(400-1200) and a₀(980) from the quark nnbar scalar currents suggests the possible identification of the f₀(980) and a₀(1450) as the lightest I=(0,1) scalar mesons in which the nnbar component is dominant