The aim of the present study was to evaluate the capability of a portable near-infrared spectrophotometer as a simple and nondestructive method to determine the nutritional constituents (glycogen, protein and moisture) closely related to pearl oyster health. The spectra of intact pearl oysters, their soft tissue, and shells were acquired using commercially available equipment with an interactance fiber optics probe. Since the second-derivative spectra of intact samples in the wavelength region

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... f 730 nm to 1000 nm were similar to those of soft tissue, and the shells did not have any particular absorption in the region, the effect of shells on spectra in this region did not appear very strong. Second-derivative spectra in the near-infrared region and multiple regression analysis were used to develop calibration equations for each constituent of soft tissue. Although the protein and moisture determinations using spectra of intact oysters were not as accurate as measurements using spectra of soft tissue, spectra from intact oysters can be used for screening. The calibration equations for glycogen were not accurate, even for the soft tissue measurements. In conclusion, we suggest that portable near-infrared spectrophotometers are suitable for the nondestructive evaluation of pearl oyster health.