Comparative effect of a previous 150-MPa treatment on the quality loss of frozen hake stored at different temperatures

Abstract

BACKGROUND

This study addresses the quality loss of European hake (Merluccius merluccius ) during frozen storage. Its objective was to comparatively analyse the effect of a previous high‐pressure processing (HPP) (150 MPa for 2 min) when different storage temperatures (−10, −18 and −30 °C) were employed. RESULTS

Most chemical quality indices (trimethylamine, TMA; dimethylamine, DMA, formaldehyde, FA; free fatty acids, FFAs) provided a marked content increase with freezing and frozen storage time, values being higher by increasing the storage temperature. Previous HPP led to an inhibitory (P < 0.05) effect on the TMA, DMA, FA and FFA formation in frozen fish kept at −10 and −18 °C, the preservative effect being higher at the highest temperature tested; however, in agreement to the low damage development, no effect could be proved on samples stored at −30 °C. Concerning lipid oxidation, peroxides formation was found low, although a slight increasing effect (P < 0.05) was implied in fish corresponding to all temperatures as a result of the previous HPP; furthermore, an inhibitory effect (P < 0.05) on fluorescent compounds formation (tertiary lipid oxidation) was evident after freezing and at month 9 for −10 °C samples. CONCLUSION

It is concluded that a 150‐MPa high‐pressure treatment may inhibit the formation of degradative molecules such as DMA, FA, TMA and FFAs during the frozen storage at −18 °C (maximum recommended) and −10 °C. However, results have indicated that lowering the storage temperature showed to be more effective than the current HPP (150 MPa for 2 min). © 2020 Society of Chemical Industry