title: Relationship between Proteolytic Activities and Cooking Loss Variability in Liver Issued from Force-Fed Mule Ducks.
abstract: We investigated liver protease activities to better understand the mechanisms responsible for losses during the cooking of Mule ducks' fatty livers. Fatty livers of similar masses (520 g) were randomly selected among a large flock of overfed male Mule ducks and divided into two groups on the basis of their cooking loss rate, L+ (high cooking losses, 36%) and L- (low cooking losses, 21%). In addition to dry matter and total lipid contents, main hepatic protease (matrix metalloproteinase 2, cathepsins, and calpains) activities were measured by zymography. The results show that L+ samples present higher total relative proteolytic activity (6.15 ± 1.07 vs 4.46 ± 0.52 for L+ and L- samples, respectively) and total lipid content (61.0 ± 3.03% vs 53.7 ± 3.22% for L+ and L- samples, respectively) than L- samples. The results imply that proteases could be involved in the fragilization of the hepatocyte structure, resulting thus in higher cooking losses in L+ samples.
authors.affiliation: UMR1388 GENEPHYSE, INRA , F-31326 Castanet-Tolosan, France.|UMR1388 GENEPHYSE, Université de Toulouse INP-ENSAT , F-31326 Castanet-Tolosan, France.|UMR1388 GENEPHYSE, Université de Toulouse INP-ENVT , F-31076 Toulouse, France.
authors.forename: Sahar
authors.initials: S
authors.lastname: Awde
authors.affiliation: UMR1388 GENEPHYSE, INRA , F-31326 Castanet-Tolosan, France.|UMR1388 GENEPHYSE, Université de Toulouse INP-ENSAT , F-31326 Castanet-Tolosan, France.|UMR1388 GENEPHYSE, Université de Toulouse INP-ENVT , F-31076 Toulouse, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Marty-Gasset
authors.affiliation: Department of Clinical Sciences and Public Health, Faculty of Veterinary Science, Mahidol University , Salaya, Nakhon Pathom 73140, Thailand.
authors.forename: Kriengkrai
authors.initials: K
authors.lastname: Prahkarnkaeo
authors.affiliation: UMR1388 GENEPHYSE, INRA , F-31326 Castanet-Tolosan, France.|UMR1388 GENEPHYSE, Université de Toulouse INP-ENSAT , F-31326 Castanet-Tolosan, France.|UMR1388 GENEPHYSE, Université de Toulouse INP-ENVT , F-31076 Toulouse, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Rémignon
keywords: cooking losses; fatty liver; proteolytic activities; zymography