Physico-Chemical Studies on the Skin and Leather of Marine Animals-XI

The Tryptic Digestion of the Collagen in Fish Skin

Abstract

The triptic digestion of the collagen in fish skin was studied with the intention of obtaining some information for the bating of fish skin. The results obtained are as follows:
(1) It was found that fish skin-collagen was digested by trypsin less easily than collagen which had bee subjected to hydrothermal shrinkage; and the collagen having lower Ts was digested somewhat more easily than that having higher Ts.
(2) The collagens were digested by trypsin at a certain temperature and above. This temperature was lower for the collagen having lower shrinkage temperature (Ts) than for that with higher Ts.
(3) The tryptic digestibility of collagen at lower temperature (20-25°C) was increased by the pretreatment with hot water, temperature of which was controlled not to cause heat-shrinkage. The increase of digestibility was remarkable for the collagen in fish skin.
(4) The collagen which had been shrunk in hot water or in urca solution was easily digested by trypsin. Horny fibre, however, was hardly digested even after it was subjected to a treatment so as to lower Ts from 60°C to 50°C.
From these results it may be said that when Ts of the skin is low, the temperature of the bating bath should be held lower.