Investigation into the effect of prior frozen storage (-20°C) on the quality of hot-smoked cod (Gadus morhua) and mackerel (Scomber scombrus)

Whole cod (Gadus morhua) and mackerel (Scomber scombrus) were frozen using a Horizontal plate freezer and frozen stored at -20°C in bags and boxes. At suitable intervals (0, 11, 22 and 33 weeks) the fish were removed from the cold store and subsequently hot smoked (cod in fillets, mackerel in gutted form) using an AFOS-Torry Mini Kiln. Both fish, frozen and smoked were analysed for their salt-soluble protein (SSP), free amino acid content, available lysine, peroxide value, free fatty acid content, fatty acid profiles, thiamine content and texture using a Stevens Texture Analyser and organoleptically assessed by ten panellists. Mackerel was also analysed for its histamine content. All smoked samples from both fish, despite their different previous histories and their different processed forms were assessed by the ten panellists as moderately acceptable products in terms of their texture, flavour, colour and saltiness even after 33 weeks. [Continues.]