engleski

Bioelectrical properties of frozen trout (Oncorynchus mykiss)

With the beginning of wider application of multivariate mathematical tools such as principal component analysis, spectroscopic methods have become more investigated in all the fields of food science, and quite recently have been applied to measure the quality-determining properties of frozen fish. In this work, the potential of bioelectrical impedance analysis was investigated to differentiate rainbow trout fillets (Oncorynchus mykiss) subjected to different freezing methods and number of freezing cycles. The resistance (R) and reactance (X) spectra recorded at 19 frequencies (1 Hz- 1 MHz) were analyzed by the principal component analysis (PCA). The following classification of the fillets was done by discriminant analysis (DA). The variables in DA were principal components obtained by PCA and the results of chemical and physical measurements. The results showed that 77% of the samples were correctly classified, which was mainly due to impedance variables. However, impedance variables were highly inter-correlated, which led to the conclusion to proceed with the studies only in higher kHz frequencies. It was concluded that reactance (X) measured at frequencies higher than 500 kHz can be used for distinguishing the fillets. Additional statistical analysis (ANOVA) showed that impedance variables can better predict number of freezing cycles than method of freezing applied.

bioelectrical ; impedance ; fish ; freezing ; quality

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