On the Softening of Roll-mops Herring. (I)

Roll-mops herring is prepared by pickling salted herring in ca. 5% acetic acid solution seasoned with sugar. With a view to study its softening which occurs in summer we have first determined the decomposition of salted herring muscle in relation to pH-value and temperature of the medium by measuring the increased soluble nitrogen and amino acid nitrogen, with the following results. 1. Figs. 1, 2, and 3 show that the optimum temperature for the decomposition of salted herring muscle at pH 3.7 ranges between 25°C and 35°C. 2. The degree of decmposition in a non-antiseptic condition depends on pH-value of the medium, increasing with it within the limits of 4.2 and 3.3 at 35°C. 3. Nearly the same experimental conditions as given above hold true for the autolyzing decomposition in an antiseptic condition, experiments being carried out at 37°C. 4. The two curves plotted in Fig. 6 showing the relation of the decomposing degree and pH-value in the antiseptic and non-antiseptic conditions run parallel with each other. In the acidic medium below pH 4.2, common putrefactive bacteria can not grow but yeast only does. The fact that the decomposing degree in antiseptic condition is less than that in non-antiseptic condition may probably be due to the presence of antiseptics and to the unfavourable temperature (at 37°C).