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Volume 40 (1999)
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Volume 40, Issue 6
Displaying 1-11 of 11 articles from this issue
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Ken-ichi KANEKO1999 Volume 40 Issue 6 Pages 417-425
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSDownload PDF (1188K) -
Mohosena Begum TANU, Tamao NOGUCHI1999 Volume 40 Issue 6 Pages 426-430_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSThe toxicity and toxic principle of the horseshoe crab Carcinoscorpius rotundicauda collected from Bangladesh during November to December, 1998 were examined. Although egg, testis and viscera were recognized to be toxic, their toxicity levels were comparatively low (under 10 MU/g; maximum of 7.4MU/g in egg). The toxin was purified by ultrafiltration through a YM-1 membrane and two types of chromatography on Bio-Gel P-2 and Bio-Rex 70. The separated toxin was analyzed by HPLC, TLC, electrophoresis, and 1H-NMR, and identified as tetrodotoxin. This is the first report on the toxicity and toxic principle of the Bangladeshi horseshoe crab.View full abstractDownload PDF (604K) -
Setsuko TABATA, Hisashi KAMIMURA, Motohiro NISHIJIMA, Shinzo TANABE1999 Volume 40 Issue 6 Pages 431-437_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSIn the manufacturing process for commercial cornstarch, corn is soaked in an aqueous solution of sodium hydrogen sulfite (NaHSO3), which reduces aflatoxin (AF) B1. The conversion product from AFB1 by treatment with NaHSO3 under similar conditions to those of the manufacturing process for cornstarch was investigated. After treatment of AFB1 standard, the conversion product (compound I) was isolated and identified by FAB-MS and NMR. A sulfo group was added to the double bond of bisfuran ring of AFB1. We applied the treatment to artificially and naturally AF-contaminated corn and confirmed that compound I was produced from AFB1. In the case of artificially AF-contaminated corn, 915ng of AFB1 was reduced, and 506ng of compound I was produced from 2, 000ng of AFB1 by NaHSO3. It was suggested that the conversion product is actually produced from AFB1 in the manufacturing process for commercial cornstarch. Effective detoxification is expected, because compound I is a watersoluble compound, and lacks the double bond in the bisfuran ring, which is activated to react with DNA.View full abstractDownload PDF (738K) -
Hiroshi AKIYAMA, Haruyo OKUNUKI, Satoko TSUZUKI, Shin-ichiro ARAMI, Hi ...1999 Volume 40 Issue 6 Pages 438-443_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSShikimic acid 3-phosphate (S-3-P) is needed as a substrate to detect the enzyme activity of 5-enolpyruvylshikimic acid 3-phosphate synthase (CP4EPSPS), which is expressed in genetically modified soybeans. Therefore, we attempted the over-expression of shikimate kinase II (SK-II) in E. coli to biosynthetically obtain S-3-P. The aroL gene encoding SK-II was constructed in the expression vector pET22b(+). The aroL expression vector was then transfected into E. coli strain BL21 using the electroporation method. The activity of the obtained aroL protein was confirmed by HPLC using an amino-silica column and incorporation of [32P] from labeled ATP to shikimic acid. The determination of the reaction product was performed by LC/MS using a carbon column and periodate treatment.
HPLC using a carbon column does not use a non-volatile buffer as the mobile phase. Thus, this method should be useful for preparing S-3-P from the crude reaction mixture of SK-II.View full abstractDownload PDF (2165K) -
Yoko KIKUCHI, Yasuhiro SHIMAMURA, Masako HIROKADO, Kazuo YASUDA, Motoh ...1999 Volume 40 Issue 6 Pages 444-454_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA method was developed for the separation and analysis of isoflavone β-glycoside conjugates (daidzin, genistin) and aglucones (daidzein, genistein) in various foods.
The isoflavones were extracted from dried samples with 80% aqueous methanol and from aqueous samples with methanol, and analyzed by reversed-phase HPLC using a gradient of methanol-water as the eluent.
The recoveries of four kinds of isoflavones added to various foods were in the range of 84-104%. The limit of detection was 0.1μg/g in samples.
Using the proposed method, 205 samples of commercial foods and other products were analyzed. Large amounts of isoflavones were detected mainly in soybeans and soy products. For example, in dry soybean seeds (n=12), daidzin was at the level of 270-1, 100μg/g, daidzein at 20-270μg/g, genistin at 370-1, 200μg/g and genistein at 21-350μg/g.View full abstractDownload PDF (1158K) -
Mieko KAMIKURA, Kunitoshi YOSHIHIRA, Yukihiro GODA1999 Volume 40 Issue 6 Pages 455-459_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSSubsidiary colors (P1 and P2) in commercial food red No. 104 (R104) were isolated as acidic forms by preparative high performance liquid chromatography (HPLC). Their structures were characterized on the basis of physicochemical evidence. The structures of P1 and P2 are 4′, 5′-dibromo-4, 5, 6, 7-tetrachloro-3′, 6′-dioxidospiro[isobenzofuran-1(3H), 9′-[9H]xanthen]-3-one and 2′, 4′, 5′-tribromo-4, 5, 6, 7-tetrachloro-3′, 6′-dioxidospiro[isobenzofuran-1(3H), 9′-[9H]xanthen]-3-one, respectively. Quantitative HPLC analyses of P1 and P2 were performed on commercial R 104 (9 samples from 4 makers). P2 was contained in all the samples in the range from 0.08% to 5.21%, while P1 was not detected in 5 samples and the highest content was 0.06%.View full abstractDownload PDF (579K) -
Kumiko SASAKI, Satoshi TAKATSUKI, Satoru NEMOTO, Masaaki IMANAKA, Shui ...1999 Volume 40 Issue 6 Pages 460-472_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSAn analytical method using GC/MS was developed for the determination of 11 alkylphenols and 2, 4-dichlorophenol (2, 4-DCP) residues in various foods. The phenolic compounds were extracted with 50% diethyl ether-hexane after the alkaline decomposition of food samples. The extracts were cleaned up on an acidic alumina column and a SAX cartridge. The phenolic compounds were derivatived with heptafluorobutyric anhydride and the derivatives or parent compounds were determined by GC/MS (SIM or SCAN). The method was applied to determine alkylphenols and 2, 4-DCP residues in 190 food samples purchased from markets. 4-Nonylphenol was found in some fish, meat and vegetables at the levels of 10-723ng/g, 9-180ng/g and 7-131ng/g, respectively. In addition, 2, 4-DCP was detected in some vegetables (2-17ng/g).View full abstractDownload PDF (1165K) -
Yahia MAHMUD, Mohosena Begum TANU, Tamao NOGUCH1999 Volume 40 Issue 6 Pages 473-480_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSOn November 16, 1998 a food poisoning incident due to ingestion of roe of Takifugu oblongus occurred in Bangladesh, affecting 8 people inclusive of 5 deaths. Their symptoms resembled those caused by tetrodotoxin (TTX) or paralytic shellfish poison (PSP). Immediately after the incident, twenty-two specimens of T. oblongus were collected from the seashore adjacent to the concerned poisoning area and their anatomical distribution of toxicity was determined. They showed a high level of toxicity in the ovary (24.5-323.8MU/g), though the toxicity levels of the other tissues, skin, muscle, liver, testis, and the viscera (except liver), were relatively low (<2-21.3MU/g). In contrast, a total of 336 specimens of three marine puffers, T. oblongus, Lagocephalus wheeleri and L. lunaris, which were collected on a regular sampling basis from Bangladesh, showed very low toxicity of less than 10MU/g in all or most tissues including gonad. The toxin partially purified from the T. oblongus specimens, as well as from the other two species, was indistinguishable from TTX in HPLC analysis. From this result and the symptoms of the victims, the causative agent in the above incident was assumed to be TTX.View full abstractDownload PDF (890K) -
Masaru KAWASAKI, Tomoko ONO, Mitsunori MURAYAMA, Masatake TOYODA, Sada ...1999 Volume 40 Issue 6 Pages 481-487_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSThiabendazole (TBZ) is a benzimidazole antibacterial agent used as an anthelminthic for livestock. 5-Hydroxythiabendazole (5-OH TBZ) is a metabolite formed by hydroxylation of TBZ in an animal's body. The recovery of 5-OH TBZ from animals by extraction in conventional TBZ analysis, which employs a strongly alkaline (pH 11.0) buffer, is as low as 50%. In order to establish a method for simultaneous analysis of TBZ and 5-OH TBZ with high recovery, we examined the optimum pH of a buffer for extraction, a suitable solvent for extraction, and a clean-up column. As a result, it was found that the optimum pH of the buffer was 9.0 and that suitable solvents were ethyl acetate (AcOEt) for pig muscle and liver, and MeCN for pig fat and cow's milk. Among the three types of solid phase extraction (SPE) clean-up columns investigated, the highest recovery for both chemicals was achieved by using an alumina N (ALN) column.View full abstractDownload PDF (698K) -
Masako HIROKADO, Keisuke KIMURA, Keiko SUZUKI, Yuki SADAMASU, Yasutaka ...1999 Volume 40 Issue 6 Pages 488-493_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSThin-layer chromatography (TLC) methods were developed to detect five kinds of natural colors in processed foods. Cochineal extract, lac color and carthamus yellow were extracted from samples with 50% aqueous methanol or 50% aqueous acetonitrile under an acidic condition, and these extracts were purified using a polyamide column with 2% aqueous ammonia-ethanol (1:1) solution as the eluant. Madder color and carthamus red were extracted from samples with 50% aqueous N, N-dimethylformamide or 50% aqueous acetonitrile, and these extracts were purified using a reversed-phase column (C18) with 50% aqueous methanol as the eluant. The natural colors in each eluate were detected by C18 reversed-phase and cellulose high performance TLC. For liquid processed foods, the extraction was not necessary. Commercial food additive grade natural colors were used as standards for TLC.
The detection limits from spiked processed foods were 100ppm for madder color, 5ppm for cochineal extract and lac color, 30-50ppm for carthamus yellow and 5-25ppm for carthamus red.
The proposed method was successfully applied to the detection of natural colors in 30 kinds of commercial processed foods whose labels indicated them to contain natural color.View full abstractDownload PDF (884K) -
Masatake TOYODA, Hiroyasu UCHIBE, Toshihiko YANAGI, Youichi KONO, Tsug ...1999 Volume 40 Issue 6 Pages 494-499_1
Published: December 05, 1999
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSSince 1977, pooled total diet samples (13 food group composites) from one district of Japan were analyzed for PCDDs, PCDFs and co-PCBs. Daily intakes of PCDDs+PCDFs decreased from 3.75 (4.68) pgTEQ/kg bw/day in 1977 to 0.92 (1.79) pgTEQ/kg bw/day in 1998, calculated at ND (not detected)=0 (and ND=half the detection limit). Over the same period, daily intake of co-PCBs decreased from 4.43 (4.72) pgTEQ/kg bw/day to 1.80 (2.06) pgTEQ/kg bw/day, calculated at ND=0 (and ND=half the detection limit). This amounts to a decrease of 76% for PCDDs+PCDFs and 59% for co-PCBs. In contrast, total dioxin intake decreased by approximately one-third over the same period. A strong correlation between decreasing dioxin intake and dioxin concentration in breast milk in the same district was found (r=0.969, total dioxin). These results show a downtrend in the dietary intake of dioxins in Japan.View full abstractDownload PDF (588K)
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