Enzymatic Hydrolysis of Yellowfin Tuna (Thunnus albacares) By-Products Using Protamex Protease 

Huong Thi My Nguyen^1,2, Khalifa Serigne Babacar Sylla², Zo Randriamahatody², Clair Donnay-Moreno², Jacques Moreau³, Luyen Thi Tran¹ and Jean Pascal Bergé²*

¹Nha Trang University, 2 Nguyen Dinh Chieu, Nha Trang, Vietnam
²IFREMER, rue de l'île d'Yeu, BP 21105, FR-44311 Nantes, France
³ENSAT, avenue de l'Agrobiopole, BP 32607 Auzeville-Tolosane, FR-31326 Castanet-Tolosan cedex, France

Article history:
Received November 20, 2009
Accepted July 6, 2010

Key words:
tuna, by-products, proteolysis, nitrogen recovery, fish protein hydrolysates

Summary:
Long-term proteolysis of tuna by-products (head, viscera and tail) by the wide spectrum protease Protamex has been investigated and compared. After hydrolysis, two fractions (soluble aqueous phase and insoluble sludge) were collected. Chemical compositions of each fraction and molecular mass distributions of soluble peptides were determined. Degrees of hydrolysis obtained after 12 h of hydrolysis of head, viscera and tail were 32.3, 16.8 and 22.2 %, respectively. Nitrogen recovery in the soluble fractions was 73.6 % for the head, 82.7 % for the viscera and 85.8 % for the tail. Lipid distribution indicated that the majority of lipids remained in the sludge. Such proteolysis appears useful for the production of very different fractions: one rich in peptides of medium to small molecular mass and poor in lipids, and another one containing the insoluble proteins and the majority of lipids.

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