抄録
In the previous article (III), it was assumed that the factor of water intake of fish flesh was closely related to the jelly strength of “Kamaboko”.
Effects of phosphate mixtures composed of pyrophosphate (P. P.Na) and tripolyphosphate (T. P. Na) at various rates were investigated in this paper, in aspects related to the factor of water intake of raw flesh and the jelly strength of “Kamaboko” made thereof.
1) It was confirmed that both actions of these phosphate mixtures upon the factor of water intake (moisture retention) of flesh and upon the jelly strength of “Kamaboko” are closely related with each other.
2) Being used at 0.3% concentration, the phosphate mixtures in which the ratios of P. P. Na to T. P. Na were 8:2, 7:3 and 6:4, respectively, were distinctly more effective than mixtures in other compositions and also than the single salt as ingradient of these mixtures.
3) When the ratio of P. P. Na and T. P. Na was 9:1, the phosphate mixture was not effective on jelly strength of “Kamaboko”.
Further, the reason why the effects of phosphate mixtures on jelly strength shift with variations in the ratio of P. P. Na to T. P. Na was studied and we discovered a new fact as follows:
4) At a certain low concentration, a strong electrolyte, for example, sodium chloride, sodium pyrophosphate and tripolyphosphate respectively, most strongly depresses the factor of water intake of flesh and jelly strength of “Kamaboko”.
The ionic concentration in such a low concentration range can be calculated as follows:
Nμ=1/10, NΣiZi2Vi=1/5, (N=1/2Σi/Zi/Vi)
(N: the number of normality, μ: ionic strength at which the factor of water intake attains to a minimun, Zi: valence of the ith ion, Vi: molar concentration of ith ion.)
It was examined how the factor of water intake of the flesh treated with P. P. Na and T. P. Na, separately, shifts on addition of HCl:
5) It was suggested the possibility of that the increase in the factor of water intake caused by P. P. Na and T. P. Na are not of the same origin.
