EFFECT OF GREEN TEA EXTRACT AND SODIUM CITRATE ON THE QUALITY OF FROZEN SILVER CARP FILLETS
Samya I. A. Hassanin
and Ahmed Z. Hssab-Alla
Processing and Quality Control Department, Central Laboratory for Aquaculture Research, Agriculture Research Center, Egypt.
Received 1/ 4/ 2012 Accepted 22/ 4/ 2012
Abstract
The objective of this study was to determine the changes in some chemical, microbiological and sensory properties of silver carp (Hypophthalmichthys molitrix) fillets treated by dipping in 200 ppm green tea extract (GTE), 2% sodium citrate (NaC) individually and in combined form 200 ppm GTE with 2% NaC (1:1, v/v) for 20 min and subjected to frozen storage at – 20±1ºC for 6 months.
In all samples the results revealed gradual decrease in total protein, fat and sensory properties. The highest scores in total protein, fat and sensorial criteria were measured in samples treated with mixture of GTE and NaC followed by samples treated with NaC then GTE as compared with control. The total volatile bases nitrogen values (TVBN), trimethylamine nitrogen (TMAN), peroxide values (PV), thiobarbituric acid values
(TBA) and psychrophilic bacterial counts (PsBC) increased during frozen storage in all samples. As well as total bacterial counts significantly (p<0.05) decreased with increasing storage time. Meanwhile the lowest values of the previously mentioned parameters were observed in samples treated with mixture of GTE and NaC.
Results indicated that, the pre-soaking of fish fillets in the mixture of 200 ppm GTE and 2% NaC (1:1- v/v) then storage at – 20±1ºC kept its freshness better than individual treatment with either GTE or NaC. It can be concluded that, GTE and NaC in combined form safe as natural preservatives owing to their antimicrobials and antioxidants properties to extend the shelf-life and maintain fish fillets qualities and nutritional value during frozen storage.
Keywords: Silver carp; Freezing; Green tea extract; Sodium citrate.
