| dc.description | Frozen storage of fish species, such as sardine, result in detrimental
changes in functional properties that determine storage
life. Sardine meat is characterized by high fat content, dark meat,
and sarcoplasmic proteins that inhibit gel formation. Washing
mince flesh with solutions such as sodium bicarbonate is very
effective for removing undesirable components. The objective of
this research was to study the effects of frozen storage at -30°C
in the myofibrillar protein fraction of sardine mince flesh washed
with 0.5% sodium bicarbonate solution. Samples of sardine-minced
flesh were washed three times with a 0.5% of sodium bicarbonate
solution and centrifuged at 3000 rpm for 15 minutes. These
samples were divided in lots of 100 g. packed in plastic bags
and stored at -30°C, and analyzed every 30 days for 150 days.
The myofibrillar proteins were extracted using a phosphate buffer
(tris HCl, KCl, EDTA, pH 7.6), and evaluated by SDS-PAGE. The
bands were analyzed and digitalized with a Gel Doc 2000 and
Quality One 4.1.1 by Bio-Rad. The main bands of myofibrillar protein
were identified by comparison of these against a prestained
molecular weight standard. After 60 days there was deterioration
of the myofibrillar protein fraction with apparent molecular weight
between 220 and 65KD, and the formation of molecular aggregates
at high molecular weight occurred. After 120 days due to
myofibrillar protein deterioration, protein and peptides with low
molecular weight were formed and increasing throughout frozen
storage. Understanding the mechanism involved in the deterioration
of the mince flesh during frozen storage we would enable to
help the establishment of quality parameters and ability to predict
storage life for that product. | |
