Vanillin assays in methanol were carried out
as recommended by Price et al. (1978), in a 30 OC water
bath with a reaction time of 20 min. The vanillin reagent
contained 4% concentrated HCl and 0.5% vanillin in
methanol. Absorbance was read in a Zeiss PMQ-I1 spectrophotometer,
at 500 nm, the wavelength of maximum