Effect of frozen storage periods on quality indices of some processed fishery products [electronic resource]

Includes bibliographic reference

This study was designed to investigate the effect of frozen storage periods at-18?C for 6 month on some physico-chemical
quality indices of processed fishery products. Two fish species; Tilapia (Oreochromis niloticus) as freshwater fish and
big eyed snapper (Latjenus spp.) as marine fish were purchased from Benha fish market. Raw whole fish samples were carefully
washed, glazed, packed in foam dishes covered with polyethylene sheet and stored under freezing conditions. Frying, grilling,
microwave cooking and boiling techniques were applied. Results showed that all quality indices were affected by storage periods
as well as cooking techniques applied. pH values recorded a high decrease at the end of storage; 90 and 180 days for big eyed
snapper and tilapia samples, respectively. Values of total volatile basic nitrogen (TVB), trimethylamine (TMA),
and thiobarbituric acid (TBA) were increased with prolonging storage periods and fluctuated. Concerning effect of
cooking techniques, it was found that pH values decreased in cooked tilapia products and increased in cooked snapper products.
However, values of TVB, TMA and TBA were increased in all studied products. In conclusion, based on our results,
it could be concluded that snapper fish samples were lower in freshness grade than tilapia samples. Freezing process
has been affected chemically quality indices especially at the end of storage. Fluctuation in quality indices are due
to fish spp., freshness degree, handling processes and frozen storage periods. Besides, different cooking techniques
are affected quality indices investigated according to thermal conditions used.

Summary in Arabic