Quality of the skin of salmon, Salmo solaris : resistance test and hydroxyproline

Abstract

This study evaluated the hydroxyproline content and resistance through physical-mechanical tests of salmon  skins submitted to tanning with chromium salts. After the skin-tanning samples were removed in the longitudinal and  transverse axes to the length of the fish’s body. The samples were distributed in a completely randomized design with two  treatments: T1 - samples in the longitudinal direction and T2 - samples in the transverse direction. For the tests of tensile  resistance determination, elongation and progressive tearing, the EMIC dynamometer was used, with the speed of sepa- ration between loads of 100 ± 10mm/min in a climatized environment (23 ± 2ºC and RH 50 ± 5 %) for 48 hours. The  thickness of the leathers analyzed ranged from 0.56 to 0.78 mm. The longitudinal-axis leathers showed greater thickness  than transverse-axis ones. The leather showed mean values for tensile resistance 10.90 N/mm 2 , elongation of 58.33% and  progressive tearing of 19.68 N/mm. The salmon skin showed a content of 1.23% hydroxyproline. This leather should be  used only in the general product manufacturing.