魚肉ソーセージの軟化現象について-3-

概要

論文の詳細を見る
In the previous paper, the authors reported the nature of softening spoilage of fish sausage as well as the characteristics of the causative microorganism which was identified as Bacillus circulans according to its morphological and physiological findings. After a culture of Bacillus circulans and other Bacillus species was suspended in a physiological saline solution, the suspension was heated for 45 minutes at 85°C in order to kill the vegetative cell, and 0.5 cc portion of the suspension was inoculated in the fish sausage paste which was sterilized beforehand. Then the mixture was incubated anaerobically in a jar filled with hydrogen gas. The softening, very alike to those found in the commercial product, was also observed in culture of Bacillus circulans kept at 30° to 34°C. Some starch granules were found crumbled down around the normal granules in microscopic examination of the softened portion, as described in the previous report. While the case of Bacillus subtilis or Bacillus cereus, none of the softening was noticed for the samples treated in the same way. Certain difference in the nutritional requirements or the presence of inhibitors for spore germination would be explored for these kinds of bacteria. (Table 1). In this connection, the capability as to the digestion of starch was investigated for Bacillus circulans and other Bacilli, as shown in the Tables 2 and 3. A liquid culture medium, containing extract of fish flesh, peptone, 1 per cent of potato starch and with or without 0.5 per cent of glucose, was employed under strict anaerobic condition as mentioned above. A remarkable increase in the activity of breaking down starch was observed rather more in aerobic culture than in anaerobic one as will be seen in Table 2. On the contrary, for the case of Bacillus circulans, predominant consumption of starch was developed under anaerobic condition and in the medium purposely absent of the glucose as shown in Table 3. To ascertain the extent of digestion of starch, sodium periodate was reacted to the alcoholic precipitates obtained from the culture after thrice repetition of precipitation and the amount of formic acid thus released was determined with 0.01 N NaOH solution required to titrate the acid. Table 4 indicates that the alkali number for Bacillus circulans is much higher than those of other organisms. Furthermore, the color intensity of iodine reaction seems to have a correlation to the amount of formic acid derived. A clear-cut divergence in the spectrum of iodine reaction of the degraded starch was found between Bacillus circulans and other species; the absorption maximum for the former was 5800 Å and the latter 6000-6200 Å, as seen in the Table 5. It is quite certain, from our findings that some Bacillus group is really capable to grow under anaerobic circumstance. In 1957, Puziss, who observed the growth of Bacillus anthracis and Bacillus cereus in an anaerobic jar displaced the air with nitrogen gas, reported that these organisms readily develop both in synthetic and nonsynthetic medium containing glucose respectively. And it is well known fact that 'flat-sour spoilage' or 'off -flavor' happened in canned foods is frequently caused by certain facultative thermophile, one of the Bacillus group.
社団法人日本水産学会の論文

魚肉ソーセージの軟化現象について-3-

スポンサーリンク

概要

著者

関連論文

スポンサーリンク