The Effect of Homogenisation and Storage on the Near-Infrared Spectra of Half Shell Pacific Oysters (Crassostrea gigas)

The effect of sample homogenisation and storage on the near-infrared spectra of Pacific Oysters (Crassostrea gigas) has been assessed. On each day of storage (Days 0, 3 and 5), spectra were collected using a Fourier transform near-infrared reflectance spectrometer in reflectance mode between 833 and 2,630 nm from whole (n = 20) and homogenised oysters (n = 20). The raw spectra were dominated by water- and fatty-acid-associated bands. Linear regression analysis of the water-associated absorbance bands occurring at 1,942 nm indicated that a physical or chemical interaction may be taking place within the oysters at or near Day 3, likely associated with transfer of liquids to and from oyster tissues. One-way analysis of variance of principal component scores and extended multiplicative scatter correction highlighted the water regions (O-H bonds) in whole oysters and the importance of N-H-related compounds in homogenised oysters throughout storage. These findings indicate the potential usefulness of near-infrared reflectance spectroscopy to monitor and evaluate degradation of oysters over time.