Chemical quality of marketed freshwater fish in Qualiobeya governorate,Egypt

Abstract

For determination of the changes in potential of hydrogen (pH), total volatile nitrogen (TVN) and trimethylamine (TMA) in three types of fish (Oreochromis niloticus, Clarias lazera and Mormyrus niloticus), 30 samples of each were collected from markets of Qalyuobia Governorate, Egypt. The results revealed that the mean value of pH in the examined samples were 6.36 ± 0.05, 6.19 ± 0.03 and 6.07 ± 0.02 for Oreochromis niloticus, Clarias Lazera and Mormyrus niloticus, respectively. The mean values of TVN were 21.58 ± 0.49 mg%; 16.73 ± 0.41 mg% and 14.15 ± 0.28 mg% for Oreochromis niloticus, Clarias Lazera and Mormyrus niloticus, respectively. The un-accepted samples were 16.67%, 6.67% and 3.33% in Oreochromis niloticus, Clarias lazera and Mormyrus niloticus, respectively. Trimethyl Amine values were 8.85 ± 0.22 mg% for Oreochromis niloticus, 6.61 ± 0.15 mg% for Clarias lazera and 5.97 ± 0.13 mg% for Mormyrus niloticus. The un-accepted samples were 20%, 13.33% and 3.33% in Oreochromis niloticus, Clarias lazera and Mormyrus niloticus, respectively.