Quality Changes During Salt-Curing of Cod (Gadus morhua) at Different Temperatures

• Published in: Journal of Aquatic Food Product Technology
• Main Authors: Oliveira H., Gonçalves A., Pedro S., Nunes M.L., Vaz-Pires P., Costa R.
• Other Authors: CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis 2016
• Subjects: Bacteria; Proteolysis; Sensory analysis; Temperature; bacalhau; Color changes; Color scale; Gadus morhua; Halophilic bacteria; Quality change; Quality product; Surface discoloration; Curing
• Online Access: https://hdl.handle.net/10216/120404; https://doi.org/10.1080/10498850.2014.994153

The main aim of this study was to assess the quality changes and their causes during cod salt-curing for up to 76 days at different temperatures and a relative humidity below 80%. Salt-curing made the fish more yellow (L*a*b* scale), a color change that is more easily detected in sensory analysis against a cream color scale. Intense proteolytic breakdown took place at 12 and 18°C, leading to a greater proteolysis degree and a higher pH. A red surface discoloration of the flesh was apparent after 76 days at 18°C due to the high number of red-halophilic bacteria. These bacteria were also responsible for the highest intensity of “off”-odors and mucus obtained under these conditions. Cod salt-curing should be done below 12°C to reduce the spoilage activity of halophilic bacteria and is best done at chill temperature (close to 6°C) to obtain a good quality product. © 2016 Taylor & Francis. The authors thank Professor Martin Adams for having revised the entire article and his useful comments. The authors also would like to thank the researchers and technicians of IPMA, I.P., who constituted the sensory panel; the group from ESAC Chemical Laboratory and the group from IPMA Chemical and Microbiology Laboratories (Division of Aquaculture and Upgrading), who provided a valuable help whenever necessary; and finally, the companies Rui Costa e Sousa & Irmão S.A. (Aveiro, Portugal) and Lugrade Bacalhau de Coimbra S.A. (Coimbra, Portugal) for supplying the salted cod.