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Volume 31, Issue 1
Displaying 1-10 of 10 articles from this issue
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Tsutomu KOYAMA1990 Volume 31 Issue 1 Pages 1-13
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
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Hiroshi INABA1990 Volume 31 Issue 1 Pages 14-21
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
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Takahisa MIYAMOTO, Atsushi YASUDA, Mitsuya SHIMODA, Keiichi FUKUI, Sho ...1990 Volume 31 Issue 1 Pages 22-29_1
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSIdentification of 14 strains of genus Bacillus isolated from corn soup was attempted by a gas chromatographic (GC) method. The identification was based on the differences in the GC pattern of volatile compounds extracted from culture broth of bacteria. After cultivation of bacteria in YBG medium (0.25% yeast extract, 0.5% bacto tryptone, 0.25% glucose, pH 7.5) at 30°C for 24hr, the culture supernatant (200ml) was charged on a Porapak Q column (2ml). The adsorbed compounds were eluted with ethyl ether (3ml) and the eluate was concentrated to 30μl under vacuum. The concentrate was analyzed by GC. Twelve different species of Bacillus, which are causative bacteria of food spoilage, were used as standards for identification of isolates. To identify the isolates, the GC data of each of the isolates and those of 20 strains of genus Bacillus were subjected to cluster analysis. For 13 strains of the isolates, the results of the GC method were consistent with those of the conventional method based on biological properties. One strain which was classified as B. circulans according to its biological properties could not be identified by the GC method, because the properties of the strain were rather different from those of B. circulans JCM 2504T used as the standard. The present method could distinguish between strains such as B. cereus and B. thuringiensis which are difficult to distinguish on the basis of their biological properties. The present GC method is expected to be useful for chemotaxonomical studies, though further research on the identification of various Bacillus species isolated from food samples by the GC method seems to be necessary.View full abstractDownload PDF (882K) -
Yuiko TAKEDA, Kunitoshi YOSHIHIRA1990 Volume 31 Issue 1 Pages 30-35_1
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSAs chlorophylls are unstable, they readily produce many kinds of decomposition products, some of which cause the oxidative deterioration of edible oil.
We reported previously a rapid determination of hydrocarbons in edible oil as an index of lipid peroxidation. By using this method, the amount of hydrocarbons formed from cell membrane was measured, and its correlation with cell damage was studied.
C3H mouse skin fibroblastic cell line L929 was considered to be the most suitable to estimate prooxidant activity among the cells (rabbit erythrocytes, primary cultured rat hepatocytes and mouse BALB 3T3 cells), because cell damage occurred in the cell suspension without spiking the chlorophyll-related compounds.
When the cell suspension containing pyropheophorbide a or pheophorbide a was exposed to light, lipids of the cell membrane were markedly peroxidized and decomposed. However, other chlorophyll-related compounds (pheophytins and chlorophylls) were not damaging. Pyropheophorbide a produced the highest hydrocarbon formation, followed by pheophorbide a. Pheophytins and chlorophylls both produced small amounts of hydrocarbons, but pheophytins produced slightly more than chlorophylls.
In C3H mouse skin fibroblastic cell line L929, there was a good correlation between the amount of pentane formed by decomposition of peroxides and cell damage (r=0.9587).View full abstractDownload PDF (590K) -
Studies on Environmental Contaminants in Food. 3Yasuyuki MURAKAMI, Shigehiko FUKUSHIMA, Takahiro NISHIMUNE, Kenji SUEK ...1990 Volume 31 Issue 1 Pages 36-43_1
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA survey of pollution by five organochlorine herbicides and two fungicides was accomplished in pond snail (Cipanogopaludina chinesis malleata), blue mussel (Mytilus edulis), river water and sea water from Yodo River and Osaka Bay. Oxadiazon, bentiocarb and CNP were detected in pond snail and blue mussel at levels of 48.0-580ppb, 60.0-80.0ppb and 11.2-35.0ppb, respectively, from May to August 1986. River water from one side and sea water contained the same herbicides as the shellfishes (pond snail and blue mussel) and the concentrations were about 1/1000 of those in the shellfishes. The presence of the herbicides, detected by ECD-GC, was confirmed by GC-mass spectrometry.View full abstractDownload PDF (944K) -
Hiromichi HAYASHI, Ashiko MIYAGAWA1990 Volume 31 Issue 1 Pages 44-50_1
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
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Yataro KOKUBO, Takashi IIDA, Seiji KANEKO, Tsutomu MARUYAMA1990 Volume 31 Issue 1 Pages 51-56_1
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSIn order to establish a method for accurately detecting small amounts of Listeria monocytogenes from raw meat, combinations of two kinds of enrichment media, EB medium as defined by the FDA method and Listeria Enrichment Broth (Merck), with four kinds of selective plating media, Oxford Formulation (Oxoid), LPM medium, McBride medium (Oxoid) and Listeria Selective Agar (Merck), were studied. In the recovery test of L. monocytogenes inoculated at less than 10 cells per one gram of minced pork meat, the combination of EB medium for the enrichment medium and Oxford Formulation or LPM medium for the selective medium demonstrated superior detection performances. In the test on 116 samples of commercial minced meat, L. monocytogenes was detected in 44 samples (37.9%) with all the combinations with the highest detection rate of 29.3% (34 positive samples) being obtained by the method of 7-day enrichment culture with EB medium followed by isolation with Oxford Formulation. Isolation with LPM medium was also successful in 33 samples. Of these, however, 6 samples were positive only when isolated on day 2 of enrichment culture, suggesting a need for carrying out isolation culture twice on days 2 and 7 of enrichment culture. Of the selective media, Oxford Formulation was particularly superior in that Listeria colonies could be macroscopically observed by aesculin hydrolysis. The detection rate obtained by the cold-enrichment method was considerably lower than that for 30°C enrichment culture with EB medium.View full abstractDownload PDF (795K) -
Tadashi SHIBATA, Sumiko TSUJI, Yoshio ITO, Kazuo MIURA, Kazuo OBARA, T ...1990 Volume 31 Issue 1 Pages 57-66_1
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSDetermination of traces of sulfites in various foods was attempted by use of the modified Rankine apparatus and para-rosaniline-formaldehyde colorimetry.
Dimedone solution and sodium azide solution, which were used for elimination aldehydes and nitrites, must be prepared freshly before use. The effects of interfering substances in samples on the color reaction could be corrected for by subtraction of the sample blank which was obtained by adding hydrogen peroxide to the sample solution before color development.
The detection limit of this method was 0.05μg/ml SO2 in test solution, corresponding to 0.5μg/g SO2 in food samples.
Sulfites in 51 kinds of foods were determined. This colorimetric microdetermination analytical method could be applied to almost all foods.View full abstractDownload PDF (927K) -
Kayoko TAKAGI, Masatake TOYODA, Yuki FUJIYAMA, Yukio SAITO1990 Volume 31 Issue 1 Pages 67-73_1
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSThe decrease in α-chaconine (CHA) and α-solanine (SOL), toxic glycoalkaloids in potatoes, during cooking by three procedures was investigated.
Raw or cooked potato samples (2g) were extracted twice with 5% acetic acid solution. The extract was purified on Sep-pak C18 and CHA and SQL contents were determined by high performance liquid chromatography. Recoveries of CHA and SQL from raw potatoes were 96.5% and 98.2%, respectively and those from cooked potatoes were 96.2% and 96.7%, respectively.
It was found that 93.9% of CHA and 95.9% of SOL remained in potatoes after boiling. These values indicate that boiling is ineffective as a means to decrease the alkaloids. Alkaloid content was reduced by microwaving by 15% in each case. In the case of deep-frying, their contents varied according to the temperature. At 150°, both alkaloids showed no decrease, and at 170°, the potatoes showed a large variation in residual alkaloids. At 210°, however, the alkaloids were partially decomposed; after 10 minutes heating, 64.9% of CHA and 59.7% of SOL remained. It was suggested that the critical temperature for the decomposition of both alkaloids in potatoes may be around 170°C.
In this study, relatively high stability of CHA and SOL in potatoes under normal home cooking conditions was confirmed.View full abstractDownload PDF (758K) -
Kazuo ONISHI, Kiyoyuki NAKAGAWA, Motohiro NISHIJIMA, Toshiko HIROSUE, ...1990 Volume 31 Issue 1 Pages 74-77_1
Published: February 05, 1990
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESS
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