Effects of Salt-curing Procedure and Smoking Temperature on Astaxanthin Stability in Smoked Salmon

The effects of salting method (injection salting compared with dry salting), smoking temperature (20°C compared with 30°C), and storage (chilled storage compared with no storage) on astaxanthin retention, surface coloration (CIE1994 L*a*b*), and process yields of cold-smoked Atlantic salmon (Salmo salar) fillets was investigated. An overall loss of 13% astaxanthin was observed when correcting for weight changes. Astaxanthin retention was 6.0% higher after smoking at 30°C than at 20°C (P < 0.01). A significant decrease in astaxanthin retention (4%) was observed after chilled storage of vacuum-packaged fillets at 1°C (P < 0.05). Salt curing was quantitatively more important to astaxanthin loss than smoking temperature and storage. Salting method did not affect astaxanthin retention, but its concentration was reduced significantly more by injection salting than with dry salting (P < 0.01). A higher overall color change (AE) was observed for dry-salted compared with injection-salted fillets (P < 0.001) and for fillets smoked at 30°C compared with 20°C (P < 0.05), and this coincided with a high variability in the colorimetric parameters in these groups. Higher product yields were obtained by injection salting compared with dry salting (10%) and after smoking at 20°C compared with 30°C (2%), P < 0.001. It is concluded that choice of processing technology may have substantial impact on important quality parameters such as color stability and variation in cold-smoked Atlantic salmon.