Post-mortem changes in three fresh water eels, Mastacembelus armatus, Macrognathus aculeatus and Mastacembelus pancalus during ice storage

Abstract

The progress of rigor-mortis and the post-mortem changes in three species of freshwater eels
during storage at room temperature (30° to 35°C) and ice (0°C) were studied. Rigor-mortis in fish sample at
room temperature, started 1hr after spiking and it reached to a maximum of 76%, 57.14% and 100% within 4
hrs after death in Mastacembelus armatus (Baim), Macrognathus aculeatus (Tara baim) and in
Mastacembelus pancalus (Guchi), respectively. In ice stored eels rigor also started within one hour of spiking
and gradually reached to a maximum of 88.89% within 3 hrs in Baim and 85.71%, 100% in Tara baim and in
Guchi respectively within 2 hrs. Rigor continued for 17, 14 and 18 hrs in Baim, Tara baim and Guchi,
respectively and then started to relax. The pH of the muscle was 6.84, 6.80 and 6.92 immediately after catch
in Baim, Tara baim and in Guchi, respectively which decreased gradually with the lapse of storage period
regardless of the storage temperature. The organoleptic quality of eels during ice storage was assessed on the
basis of sensory parameters. Baim was found in acceptable conditions for 24 days whereas Tara baim and
Guchi were in acceptable condition for 28 days in ice storage. Percent moisture content increased but protein
and lipid contents decreased in almost all the fish samples with the lapse of storage period but a little change
was observed in ash content. The TVB-N, peroxide and NPN value remained within the recommended value
up to 24 days in Baim and 28 days in Tara baim and Guchi. The initial bacterial loads were 6.5×103,
6.2×103 And 6.3×103 CFU/g in Baim, Tara baim and in Guchi, respectively. At the end of the 24 days of
ice storage, bacterial load increased in all the fish samples.