Research Article: Changes of amino acids and proximate compositions in freshwater farmed beluga sturgeon (Huso huso) caviar

This work is mainly concerned with the changes of amino acids and proximate compositions of Caspian Sea Beluga sturgeon (Huso huso) caviar after culture in freshwater. Proximate compositions did no differ between wild and farmed Beluga caviar (p>۰.۰۵). Eighteen amino acids were identified in wild and farmed Beluga caviars, but they had significant differences in some amino acids content. Isoleucine was the most abundant amino acid among total amino acids, which was ۵۰.۱۷±۲.۷۵ (mg/g) in wild caviar and was ۲۶.۸۳±۰.۸۲ (mg/g) in farmed ones (p<۰.۰۵). The essential amino acids content (EAA), in wild and farmed caviar were ۱۳۲.۶۶±۶.۸ and ۱۱۰.۱۶±۷.۳۵ (mg/g), nonessential amino acids (NEAA) were ۱۰۷.۹۲±۵.۶۸ and ۱۲۱.۷۹±۴.۰۸ (mg/g) and total amino acids (TAA) were ۲۴۰.۵۸±۱۲.۴۸ and ۲۳۱.۹۵±۱۱.۴۳ (mg/g) respectively (p>۰.۰۵). But the ratio of EAA/NEAA in wild samples ۱.۲۳±۰ was significantly higher than farmed ones ۰.۹±۰.۰۳ (p<۰.۰۵). Functional amino acids (FAA) in wild and farmed samples were ۹۶.۱±۸.۶۶ and ۱۱۶.۸±۹.۶۵ (mg/g) (p>۰.۰۵), but the ratio of (FAA/TAA) in wild caviar was ۰.۴۰±۰.۰۲ and in farmed one was ۰.۵۰±۰.۰۲, which was significantly higher in farmed caviar (p<۰.۰۵). Delicious amino acids (DAA) were ۵۴.۹±۱.۸۹ and ۵۴.۸۶±۲.۰۱ (mg/g) in wild and farmed caviar and the ratio of (DAA/TAA) were ۰.۲۳±۰ and ۰.۲۴±۰ (p>۰.۰۵) respectively. The present study indicated that, farmed Beluga caviars were well balanced with the essential amino acids, functional amino acids and had a good EAA/NEAA ratio, so can be considered as a valuable food resource as well as the wild ones.

Keywords:

Amino acids , Beluga sturgeon , Caspian Sea , Caviar , Freshwater