1983 Volume 30 Issue 10 Pages 544-551
This study was conducted in order to define the characteristics of infrared and near infrared spectra of dried laver (Porphyra yezoensis) so that near infrared diffuse reflectance method might be applied for a nondestructive analysis of chemical composition. By comparing the infrared spectra measured by KBr-pellet and that by ATR methods, near infrared spectra in 1.1 to 2.5μm region were assigned in conjection with a substance related to the quality. (1) Infrared spectra consisting of the major 6 absorption bands were assigned to Amide I, Amide II and Amide III, and fundamental vibration of C-H and C-O groups. (2) Near infrared spectra consisting of about 35 absorption bands were also assigned to various overtone and combination vibrations of C-H, N-H, O-H or C=O groups. (3) Both the infrared and near infrared spectra showed a general tendency that the better the grade of the quality was, the more a content of protein was, and by contrariesthe less a content of carbohydrate was. (4) An organic solvent- or water- extractability of substance related to near infrared bands was assigned qualitatively measuring organic solvent- or water- extracted laver samples, respectively. (5) The effect of moisture content of the sample on near infraed spectrum showed in some wavelength regions in addition to absorption bands related to water itself. This effect is independent upon the grade of the quality and the change of spectrum is reversible to moisture content.
