Non-invasive assessment of packaged cod freeze-thaw history by hyperspectral imaging

Freezing, storage and thawing all significantly affect the quality of seafood products. In this article, we explore the potential for estimating these parameters using online optical spectroscopic measurements. Fillets of cod were vacuum packed and underwent different programs of freezing, thawing and storage. Hyperspectral imaging of the fillets was performed at each program stage. Both single and double-frozen samples are studied. Different freezing and thawing methods are also investigated. Multivariate analysis of the hyperspectral data show that freezing history can clearly be determined on samples in the frozen state and to some degree on samples in the thawed state. Analysis of the data shows a less clear distinction between methods of thawing. Measurement on samples after a year of storage still showed the ability to classify samples based on their freezing history. These results show that hyperspectral technology can be used to evaluate the freeze-thaw history and potentially estimate quality of cod products in a manner that meets the speed and non-invasive requirements of an industrial setting.