Assessment of storage shelf life of European squid (cephalopod: Loliginidae, Loligo vulgaris) by bioelectrical impedance measurements

The aim of this study was to examine the possibility of storage shelf life assessment of refrigerated squid Loligo vulgaris by bioelectrical impedance measurements. Fresh squid samples were kept in the refrigerator at 4 ± 1 °C during the period of 15 days and were examined every two days, starting on the 4th day post-mortem . The Agilent 4294A Precision Impedance Analyzer with needle-type multi electrode array arranged in bipolar configuration was used to measure impedance magnitude (|Z|) and phase ( φ ) at 200 frequencies from 100 Hz to 100 MHz. Protein solubility, color parameters and textural parameters have also been determined. Results showed that impedance (phase), color ( a* ) and protein solubility were highly correlated with the duration of storage, while texture parameters showed only moderate correlation. The correlation between phase and protein solubility was moderate until phase and texture parameters showed no correlation. The phase ( φ ) measured at 1 MHz showed a potential for the assessment of storage shelf life of the refrigerated European squid by grouping the samples into 3 distinctive groups post rigor mortis.