Extractive compounds estimated with GC–MS in relative extractability compared to the corresponding control. For each chromatogram, the area of the compound was divided by area of the internal standard and normalized to sample weight; the values thus obtained for treated samples were divided by the values of the corresponding controls to estimate the percentage of residual extractive compounds. V = vanillin, AV = acetovanillone, HV-OH = homovanillyl alcohol, VA = vanillic acid, VP-OH = vanilpropanol.