Lt. Hansen et al., EFFECTS OF SALT AND STORAGE-TEMPERATURE ON CHEMICAL, MICROBIOLOGICAL AND SENSORY CHANGES IN COLD-SMOKED SALMON, Food research international, 28(2), 1995, pp. 123-130
Chemical, microbiological and sensory changes during storage of vacuum
-packed cold-smoked salmon were studied using a factorial experimental
design with two storage temperatures (5 and 10 degrees C) and two sal
t levels (2.2 and 4.6%). The spoilage characteristics were typical of
microbiological activity in all treatments, but there was no relation
between sensory changes and any of the microbiological numbers (total
viable counts, total psychrotrophes, lactic acid bacteria or Enterobac
teriaceae). Total viable counts typically reached 10(8) cfu/g weeks be
fore sensory rejection. Acetic acid, hypoxanthine, trimethylamine and
ethanol concentrations increased with storage time in all treatments.
The increase in ethanol depended on salt concentration but not storage
temperature. Absolute values of trimethylamine ranged from 2-8 mg TMA
-N/100 g initially, to 10 mg TMA-N/100 g at sensory rejection. Acetic
acid levels increased with temperature and decreased with salt concent
ration, but varied between 12-23 mu mol/g at rejection. Initial concen
trations of hypoxanthine increased from 2-3 mu mol/g to maximum 8-9 mu
mol/g, with values of 5-7 mu mol/g indicating the limit of sensory ac
ceptability. Hypoxanthine was considered to be the best objective indi
cator for sensory quality of cold-smoked salmon.