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Volume 30, Issue 1
Displaying 1-11 of 11 articles from this issue
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Harumi OKUYAMA, Keiko SAKAI, Atsuko MORIUCHI1989 Volume 30 Issue 1 Pages 1-7
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSDownload PDF (963K) -
Yasutaka KATSUKI, Shigeru MATSUMOTO, Hideo TSUYUKI1989 Volume 30 Issue 1 Pages 8-13_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSTo examine the autoxidation of unsaturated triglycerides, experiments were carried out on purified trilinolein (TL), by introducing oxygen at 75°C into an apparatus similar to that employed previously. Methyl linoleate (ML) prepared from the same source was used for comparison. Samples were taken at various oxidation times, and several chemical constants such as peroxide value (POV), thiobarbituric acid value (TBAV), etc. were measured. The IR and UV absorption spectra were also examined. Further, the antioxidative effect of α-tocopherol (α-Toc) and the synergism of ascorbic acid (AA) were studied. α-Toc and AA (3mM/kg) were added TL, and the residual amounts of them in the course of oxidation were followed by high performance liquid chromatography. The relation between the decrease of residual α-Toc and AA and the increase of POV of TL was examined.
The results obtained were as follows. The induction period of oxidation was much shorter in TL than in ML. The rate of oxidation or decomposition of peroxides was faster in TL than in ML after the induction periods. The maximum TBAV of TL was found to be about 1/3 that of ML. The antioxidative effect of α-Toc and the synergistic effect of AA were clearly observed in both TL and ML. It was observed that α-Toc and AA decreased more gradually when both were present than either one alone. The results indicate that α-Toc and AA acted as mutually protective substances, and when both disappeared at nearly the same time, POV increased rapidly.View full abstractDownload PDF (656K) -
Sumiko TSUJI, Shunjiro OGAWA, Tadashi SHIBATA, Yoshio ITO1989 Volume 30 Issue 1 Pages 14-18_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSBoric acid in foods has been rapidly and simply determined by means of the curcumin color-developing reaction under non-aqueous conditions after chelate extraction of boric acid with 2-ethyl-1, 3-hexanediol (EHD).
Boric acid in the sample was directly extracted into hexane-butyl acetate (4:1) solution containing 5% EHD under acid conditions, then 3ml of extract was used for the color-developing reaction. Boric acid in the extract was reacted with curcumin in glacial acetic acid and conc. sulfuric acid. After the reaction, water was added to the reaction mixture in order to decompose protonated curcumin (blank color), and then the reaction mixture was diluted with acetone to constant volume and the absorbance was measured at 550nm. More than 97.0% of spiked boric acid was recovered from 6 kinds of foods at the 10, 100 and 500μg/g level. The detection limit of boric acid was 0.3μg/g of sample.View full abstractDownload PDF (564K) -
Michiko KOBATAKE, Yasuhide TONOGAI, Kayoko KOBAYASHI, Yoshio ITO1989 Volume 30 Issue 1 Pages 19-26_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSPreviously, we reported on the amount of T-VBN produced by yeasts or bacteria. Candida lipolytica produced the largest amount of T-VBN among the 5 yeast species tested, while Staphylococcus epidermidis produced the smallest amount, and Pseudomonas fluorescens produced the largest amount among the 4 bacterial species tested. In this paper, the microbiological and chemical changes of these 3 species were compared. C. lipolytica, S. epidermidis and P. fluorescens were inoculated singly or as mixtures into 3 different kinds of sterile seafood homogenate (common mackerel, black tiger shrimp and neon flying squid), and incubated at either 5, 15 or 25°C. The time courses of viable counts, pH values, and TVB-N values determined according to the microdiffusion method of Conway were observed for up to 7 days.
(1) Viable counts: The growth curves of C. lipolytica at 15 and 25°C showed gradual slopes, and reached the stationary phase on day 7. The growth curves of P. fluorescens and a mixture containing C. lipolytica, S. epidermidis and P. fluorescens at 15 and 25°C reached the stationary phases on day 2. The growth curves of S. epidermidis at 5 and 15°C were lower than those of C. lipolytica, P. fluorescens and a mixture of all three.
(2) pH: The pH values in the seafood homogenate inoculated with C. lipolytica, P. fluorescens and a mixture of all three increased with temperature and duration of incubation.
(3) TVB-N: Whereas the viable counts at 25°C of C. lipolytica were less than those of P. fluorescens, S. epidermidis and the mixture, the production of TVB-N by C. lipolytica was at almost the same levels as those of P. fluorescens and the mixture, and considerably more than that of S. epidermidis. The results of the previous and present experiments have thus confirmed that the yeasts produced the same spoilage phenomenon as the bacteria.View full abstractDownload PDF (799K) -
Microbiological Studies on Safety of Raw Ham (1)Hideo NAKAJIMA, Hiroyuki YAMANAKA, Takashi SAMESHIMA, Shigeru AKIYAMA, ...1989 Volume 30 Issue 1 Pages 27-31_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSWater activity (Aw), salt content and microbiological changes during the processing of raw ham were investigated.
Depression of Aw and increase of salt content occurred during the 17-days curing period and the subsequent 14-days drying period. Though the predominant species were gram-negative bacteria and Micrococcus before the curing period, it changed to Micrococcus during the 17-days curing period. A 4 log decrease of total counts occurred during processing, and coliforms and Enterococcus were inactivated during the curing or drying period. CTEA system for evaluation of the microbiological quality of raw ham is proposed.View full abstractDownload PDF (555K) -
Ayumu NAGAHARA, Katsunori OHSHITA, Seiichi NASUNO1989 Volume 30 Issue 1 Pages 32-35_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSThe mutagenicity of unknown compounds formed from soy sauce and sodium nitrite was studied at pH 3.0 and pH 4.6 under in vivo conditions (phosphate buffer), in vivo-in vitro conditions (the stomach removed from rats) and in vivo conditions (the stomach of rats). The remaining amounts of sodium nitrite were determined to evaluate consumption for the formation of mutagens.
When in vitro conditions were used, the soy sauce and sodium nitrite mixture induced increasing numbers of mutations of TA100 with increasing sodium nitrite concentrations (250 to 2, 300ppm). No remaining sodium nitrite was detected, showing that soy sauce components had entirely reacted with sodium nitrite, presumably to form mutagens. When the removed stomach was employed, the soy sauce and sodium nitrite mixture also weakly induced mutations as the sodium nitrite concentration was increased (250 to 2, 300ppm). No remaining sodium nitrite was observed. When the stomach of rats was utilized, the soy sauce and sodium nitrite mixture did not induce mutations. No remaining sodium nitrite, however, was found in the mixture. This was ascribed to rapid absorption of sodium nitrite into the gastric mucosa, suggesting that there was no formation of mutagenic compounds. From these results, we conclude that soy sauce did not yield mutagenic products with sodium nitrite under the conditions found in the human gastric tract.View full abstractDownload PDF (410K) -
Sumie MORISAKI, Tadashi NAGATA, Takayo NINOMIYA, Satoshi NAKAMA1989 Volume 30 Issue 1 Pages 36-41_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA simple and practical method was developed for quantitative analysis of tributyltin (TBT) in fish and shellfish by gas chromatography. Samples were homogenized in centrifugal tubes with a mixture of hydrochloric acid and methanol, to which hexane was added to extract TBT by shaking, followed by centrifugal separation in the form of tributyltin chloride (TBTC). The extract was charged onto a silica gel column which had been pretreated with hydrochloric acid. TBTC was eluted with hexane, concentrated in a rotary evaporator, and determined by gas chromatography on a Thermon Hg column.
The mean recovery from yellowtail fish of bis(tributyltin)oxide (TBTO)added at the level of 0.2μg/g was 84.8% (n=4), and those from scorpionfish after addition of 0.08 and 0.4μg/g were 79.0 and 89.4% (n=4), respectively. The detection limit of TBTO was 0.02μg/g in samples. The concentration of TBTO in cultured yellowtails ranged between 0.02 and 0.9μg/g, and that in natural fishes ranged between 0 and 0.64μg/g, as determined by this method.View full abstractDownload PDF (534K) -
Yutaka YONEDA, Noriko FURUSHIRO, Ryoukichi ANDOH1989 Volume 30 Issue 1 Pages 42-47_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA simple and sensitive method for determination of residual tetracyclines (TCs) in meats by high performance liquid chromatography (HPLC) after chelate formation with magnesium ion was developed.
Oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) in a sample were extracted with McIlvaine buffer (pH 5.5)-methanol (3:7). The extract was concentrated and defatted with petroleum ether. The defatted solution was passed through a Sep-pak C18 cartridge. After washing the cartridge with water, TCs were eluted with methanol. The eluate was evaporated to dryness. The residue was dissolved in 1M imidazole buffer containing 50mM magnesium acetate-methanol (77:23), and the solution was injected into a YMC-PACK ODS HPLC column. TCs were separated with 1M imidazole buffer containing 50 mM magnesium acetate-methanol (77:23) as a mobile phase and detected with a flourometric detector.
The recoveries of TCs from beef fortified with 0.5, 2ppm of OTC and TC and 2, 10ppm of CTC were 81.7-82.8% for OTC, 65.9-80.7% for TC and 53.0-80.1% for CTC.View full abstractDownload PDF (596K) -
Takashi SUZUKI, Takashi ISHIZAKA, Kumiko SASAKI, Yukio SAITO, Yutaka F ...1989 Volume 30 Issue 1 Pages 48-53_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA gas chromatographic method for quantitative analysis of organochlorine pesticides and chlorpyrifos in meats has been established. The extracted fats was subjected to silica gel dry column chromatography and further cleaned up by Florisil minicolumn chromatography. As a result of investigation of imported Australian meats, aldrin, heptachlor and chlorpyrifos were not detected in any meat, and dieldrin was found over the tentative maximum residue limit (0.2 ppm) in only one case of cattle. Among the 4 kinds of meats investigated, cattle and sheep meat showed similar low residue levels but the residue levels of p, p′-DDT, p, p′-DDE, dieldrin and heptachlor epoxide in horse meat were relatively high compared to the other meats.View full abstractDownload PDF (541K) -
Satoko KATAYAMA, Yoko TSUDA, Tatsutoshi TAKARAI, Tadashi KIRIGAYA, Mas ...1989 Volume 30 Issue 1 Pages 54-58_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA clean-up method using a Florisil column was developed for the determination of mono-, di- and triisopropyl citrates in foods by gas chromatography.
Isopropyl citrates in foods were extracted with ethyl acetate or hexane and transferred to acetonitrile. The extract was methylated with diazomethane and applied to the Florisil column deactivated with 15% water. The Florisil column was washed with hexane-ether (4:1) mixture, and methylated isopropyl citrates were eluted with hexane-ether (1:1) mixture. The eluate was evaporated to dryness and the residue was dissolved in acetone, then methylated isopropyl citrates were determined by gas chromatography.
By these procedures, five kinds of isopropyl citrates that have different polarity were able to be cleaned up simultaneously.
Recoveries from butter, margarine and edible oil were 91.0-103.0%. The detection limits were 1μg/g of sample.View full abstractDownload PDF (548K) -
Yukinori NARAZAKI, Hironori HIRAKAWA, Ryuichi OHTSU, Kazumi FUKAMACHI1989 Volume 30 Issue 1 Pages 59-68_1
Published: February 05, 1989
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESS
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