Salt and smoke simultaneously affect chemical and sensory quality of cold-smoked salmon during 5 degrees C storage predicted using factorial design.

Simultaneous effect of salt and smoke on chemical indices of cold-smoked salmon and on its shelf life, estimated by sensory analysis, was investigated during vacuum-packed storage at 5 degrees C. Salting salmon immediately decreased the pH in the flesh, probably due to the increase of the ionic force, then pH remained constant during storage. Total volatile base nitrogen and trimethylamine productions were mainly inhibited by the salt concentration in the flesh, whereas phenol had no effect. A highly synergistic effect between the two factors was observed on the shelf life response. When a high level of salt (5% wt/wt) or phenol (1 mg 100 g(-1)) was added separately, shelf life did not exceed 1 week, whereas it could reach more than 10 weeks when salt and smoke were added simultaneously. Different combinations were examined for shelf life characteristics of the product. For instance, 2 and 3% (wt/wt) of salt with, respectively, 0.80 and 0.45 mg 100 g(-1) of phenol were sufficient for a 4-week shelf life, satisfying most of French cold-smoked salmon producers and consumers. Correlation between microbiological responses measured in a previous study and chemical and sensory data were also established.