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On the other hand, canning and filling media are main factors
affected chemical composition. Canned product type C had a high
content of lipid resulting fried carrot and onion used. These changes
in composition of canned fish may be due to denaturation protein,
oxidation and hydrolysis of lipids as affected by thermal process.
These observations are in agreement with those mentioned by Arafa,
(1994); Abo-Taleb (1997); Ibrahim (1999); Abd-El-Ghafour (1999 &
2004); El-Sherif (2001).

3-2- Quality parameters
Table (2) exhibits the effect of pre-frozen storage and canning
on quality parameters of carp fillets. pH value was increased to 6.77
in frozen sample comparing with initial value (6.34). This is due
to changes in proteinous compounds and formation volatile basic
nitrogen components as affected by biochemical changes under low
temperature. TVB content was increased from 13.93 of fresh sample
to 23.10 mg/100 g sample after 6 months of frozen storage. Also,
values of TMA were sharply increased from 0.35 to 2.68 mg/ 100
g sample at the end of frozen storage (180 days). This increment in
TVB may be due to microbial activity under low temperature. The
same trend was observed in TBARS value where it was 0.06 in
raw fish increased to 1.30 mg malonaldhyde/kg flesh; due to lipid
hydrolysis and secondary products formation under low temperature.
These phenomena were reported by Abo-Zeid (1995); Hanafy (2002)
and Sarhan (2003); Ibrahim and El-Sherif (2008) and Ibrahim and
Dosuky (2009).

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