Laver grade was appraised by the photoacoustic spectroscopy. The result sho
ws that the grade of laver seems to have the relation with the shape of the
absorption spectrum. The significant difference between dries and heated l
aver was found in the wavelength range of 480-620nm. However, the absorptio
n peaks due to Chrollophyl-a at 430 and 680 nm was observed not only for dr
ied but also heated laver. The photoacoustic method has the advantage over
the existing standard optical methods, i.e. transmittance or reflectance, w
hich are hard to detect such clear peaks due to pigments, since the non-uni
formity of the laver sheet surface directly affect on the measurements.