Abstract:
The present study evaluated the effect of packagin
g (air, vacuum) with or without
addition of sodium acetate (2%
W
/V) on shelf-life extension of rainbow trout
(
Oncorhynchus mykiss
) under refrigeration, for a period of 18 days. Fou
r different
treatments were tested: CAP: control air pack; SAAP
: sodium acetate treated aerobic
packaging; VP: vacuum packaging in the absence of s
odium acetate; and SAVP, sodium
acetate under VP. Trimethylamine nitrogen (TMA-N),
free fatty acids (FFA) and
peroxide values (PV) of SAVP samples were lower com
pared to the other treatments
during the entire refrigerated storage period. In t
he present study, the thiobarbituric acid
(TBA) level showed fluctuations during storage indi
cating that TBA values may not
reveal the actual rate of lipid oxidation. Total vi
able counts for fresh rainbow trout stored
aerobically exceeded 7 log CFU g
-1
after 10-11 days, while treatments SAAP and VP
reached the same value on days 12 and 16, respectiv
ely. In contrast, SAVP samples did
not reach this value throughout the 18-day. Psychro
trophic counts of SAVP samples were
significantly (P
<
0.05) lower compared to the control samples during
storage period. As
regards sensory evaluation, shelf-life of trout was
longest for SAVP (15-16 days), followed
by VP (12-13 days), SAAP (9-10 days), and CAP sampl
es (6-7 days). The results indicated
that the combined effect of vacuum packaging and so
dium acetate on fish samples
preserved their good quality characteristics and ex
tended the shelf-life of the treated
samples during refrigerated storage, as supported b
y the results of microbiological,
chemical, and sensory evaluation analyses.
Keywords:
Packaging, Quality characteristics, Rainbow trout,
Sodium acetate.
