魚肉ねり製品の研究-IX

Abstract

In this paper, discolouration of a colour (new coccin) added to fish sausage products was studied. Determination of degree of the discolouration was carried out according to the following procedure: The colour is extracted into an ammoniacal alcoholic solution from fish sausage, and the optical density of the extract was measured with a Beckman electrophotometer. Then the rate of discolouration (D) is calculated as follows: D(%)=100(Eo-Et)/Eo Where Eo represents the optical density of the colour solution prepared by extracting a freshly manufactured fish sausage, and Et that of the colour solution from a fish sausage stored for t days. The condition of extracting food colour from the sausage and the experimental error in optical density of this method were examined. The result indicates that food colour in quantitatively extracted from a fish sausages within an error smaller than 6%, although different individuals of identical products do not always lead to an identical result. Employing this method, discolouration of the food colour as added to 11 kinds of fish sausage products was followed up. Said 11 kinds of fish sausages were as follows: The sausages made from the white flesh of fish and the reddish flesh, some being added and the others not added with phosphates, and the fish sausages mixed with drained bean-curd up to 20 and 40%, respectively. The relation between the discolouration and the putrefaction was also observed. The results may be outlined as follows: 1) The food colour “new coccin” which was added to fish sausages gradualy discolours with the lapse of time after the completion of manufacture. In the case of fish sausage products which are at the threshold of putrefaction, the degree of discolouration is about 20%. Afterwards, however, the discolouration in suddenly accelerated with the advance of putrefaction. This result suggests that discolouration of fish sausage products can be attributed chiefly to the propagation of bacteria. 2) Addition of nitrite accelerates the discolouration of new coccin. Contrary to the general conception that fish sausages made from reddish flesh are more liable to be discoloured in comparison with those made from white flesh, the present experimental result indicates that if the customary nitrite treatment is omitted, the degree of discolouration will remain distinctly less in sausages made from reddish flesh than in those from white flesh. This suggests that, in the case of sausages made from reddish flesh of fish, the nitrite, be effective in stabilizing the myoglobin as it may, undesirably accelerates the discolouration of the food colour added to these products.