Abstract
The model weaning foods were preparated by enriching with various iron preparations to the powdered bread, and the possible effect by the form of these preparations on rancidity of enriched foods have been observed. The iron salts used in this examination were listed in Table 1. These iron salts were enriched in 10mg per cent concentration into the weaning foods, and these enriched samples were stored in an incubator at 30°C together with the unenriched samples. Degree of rancidity were determined by thiobarbituric acid (TBA) method at weekly intervals. Tests were also carried out in the pasteurized section and unpasteurized section.
The TBA pigments developed from samples have the absorption maxima at 532mμ and 454mμ The former of a red color was the same as obtained from malondialdehyde prepared from ethoxypropane, and the latter of a yellow color was the same as the absorption obtained from pure saturated aliphatic aldehydes (Fig. 1-2).
In the condition described above, iron salts in the samples were found to promote the rancidity (Fig. 3 to 7). Samples containing insoluble inorganic complex showed slight rancidity, but the samples containing soluble organic complexes, which were consisted predominantly from ferrous salt, showed remarkable rancidity comparing with the samples used the other iron preparations. These complexes were unstable for air and light. Samples containing ferric chloride and ferrous sulfate having ionisation forms also showed remarkable rancidity. Using sodium ferric pyrophosphate or ferric pyrophosphate, rancidity was very slight. Therefore it was proved that these pyrophosphates were most effective enrichments for weaning foods and soluble iron salts such as ferrous gluconate or lactate were not suitable as enrichments because of these unstabilities.
