Keishi Amano

A STUDY ON THE MICROBIOASSAY OF FURYLFURAMIDE AS FOOD PRESERVATIVES-II

Nitrofurazone and nitrofurylacrylamide have been replaced by furylfuramide (2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide: FF) as a preservative for the fish sausage preparation in Japan after July 5, 1965. It has been noticed by the manufacturers that a decrease in the amount of FF occurred during the preparation of fish sausage, and it became desirable to estimate actual amount of FF remained in the product in order to examine the effectiveness of preservative in the products and to check whether a maximum permissible amount of the use is being held by the manufacturers. The present paper deals with the determination of FF added to buffer solution, eggwhite, raw and cooked fish meat, and fish sausage by microbioassay using Bacillus natto as a test organism. 1. In buffer solution, FF was found to be quite stable at pH 6.0 and gave almost 100% recovery, and the rate of recovery lowered if pH was shifted to a value of 8.0, as indicated in Tables 1 and 2. A fairly good recovery was observed when FF was mixed into raw eggwhite solution in spite of its alkaline nature, however, the recovery rate decreased on heating, especially in the higher concentration of eggwhite (Table 3). 2. No remarkable difference in the recovery rate of FF between raw and cooked fish meat, which include Alaska pollack, whale, tuna and shark meat. The rates lie between 30 and 60% (Tables 5 and 6). 3. FF in fish sausage, treated similarly as in commercial processing of the plant, showed a decrease to one-third of the amount originally added.

Food Hygienical Studies on Japanese Fish-cake Products.-III

In the commercial fish cake production, potato and wheat starch frequently used to give more elasticity to the products, especially when the raw meat of fish are not capable of forming sufficient jelly-strength. Although why the jelly-strength of “Kamaboko” can be assisted by mixing starch has not yet proved, suitable gelatinization of starch granules is supposed to be aprobable factor to attain elasticity of the finished products. Because raw starch granules alone will be no use to make up physical nature peculiar to fish-cake. Besides this, it has already been found that starch in the natural state is not only resistant to digestion when given to some test animals, but also difficult to convert into a lower moleocular compound in the presence of diastase preparation extracted from fungi (Aspergillus oryzae). Among the varieties of starch, potato starch is less digestible than that of rice, wheat or corn. Therefore the gelatinization of starch, especially that of potato starch is a significant problem from the point of view of both jelly-strength and digestibility of the products. In the present experiment, sections of various fish-cakes, each about 15 microns thick, measuring its temperature before fixing in Carbowax, were examined under microscope or petrographic microscope to ascertain the presence of ungelatinized starch granules. As will be seen in Figs 1 and II, they could not be detected in one sample of “Hampen”, when temperature at its core reached 69-70°C, while in another, there remained abundant ungelatinized particles of starch with a maximum temperature being kept at 60.5°C. In some cases of “Kameboko” tested, there were found a few ungelatinized particles among fully gelatinized ones, inspite that cooking temperature for them was considered well enough. Although the reasonable explanation for the remaining of these exceptional starch particles can not be approached, yet some extraordinary character of the particle itself and the amount of water locally surrounding it may be assumed as associated factors in this phenomenon. It has also been noticed that starch added to a fish meat with less jelly-strength is liable to be gelatinize more than the same starch added to a meat having more jelly-strength. Studies concerning these subjects must be undertaken in future.