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Volume 43 (2002)
- Issue 6 Pages 323-
- Issue 5 Pages 267-
- Issue 4 Pages 191-
- Issue 3 Pages 115-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 43, Issue 6
Displaying 1-12 of 12 articles from this issue
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Originals
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Keiko TANAKA, Kouji TAKEYA, Yukiko HARA-KUDO2002 Volume 43 Issue 6 Pages 323-329
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSThe inhibition of bacterial growth in thawed cake kept under refrigeration and rapid evaluation methods for microbiological quality of the cake were investigated. The effects of the freezing temperature and the addition of ethanol or emulsifier on bacterial numbers in a cake model after storage for 72 hr at 10°C following the thawing process were also studied. Bacterial growth in the cake model was inhibited by the additives under various freezing conditions. In addition, rapid evaluation methods for estimating bacterial numbers in the cake model after incubation for 72 hr at 10°C were studied. High correlations were found between bacterial numbers in the cake model incubated for 24 hr at 20°C and for 6 hr at 35°C with tryptic soy broth and that of the cake model incubated for 72 hr at 10°C. This result indicated that rapid evaluation by incubation for 24 hr at 20°C or for 6 hr at 35°C with tryptic soy broth can be used to predict the bacterial numbers in a cake model after incubation for 72 hr at 10°C. Furthermore, the ATP-bioluminescence method was applied to shorten the testing time, because culture on an agar medium was not necessary.View full abstractDownload PDF (922K) -
Yukari TSUMURA, Kimihiko YOSHII, Susumu ISHIMITSU, Yasuhide TONOGAI2002 Volume 43 Issue 6 Pages 330-338
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSTwenty-one N-methylcarbamates (NMCs) and 12 of their metabolites or isomers in citrus fruits were simultaneously determined avoiding use of dichloromethane. NMCs in lemon, orange, and grapefruit were extracted with acetone, then the acetone was evaporated off and sodium chloride was added before extraction with ethyl acetate. The extract was evaporated and the residue was cleaned up on a combined mini-column set of Supelclean ENVI-Carb and Mega Bond Elut SAX cartridges. NMCs were determined by HPLC with post-column reaction and fluorescence detection. All of the NMCs in the orange sample were determined without interfering peaks. However 8 NMCs in lemon extract and 10 NMCs in grapefruit extract were not detected because interfering peaks appeared at similar retention times to those of the NMCs. These NMCs were determined using LC/MS (SIM) and were well recovered. Eighty-three data sets obtained by HPLC and LC/MS showed good similarity, with r2=0.9178. Recoveries were 60.1 to 97.8% for major NMCs at a fortification level of 0.1 ppm. The limit of detection by HPLC was 0.005 ppm NMCs in samples and a similar level applied to LC/MS.View full abstractDownload PDF (930K) -
Yukihiro GODA, Hiroshi AKIYAMA, Emiko SUYAMA, Satoshi TAKAHASHI, Junei ...2002 Volume 43 Issue 6 Pages 339-347
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSSoyasaponins and isoflavones are main secondary metabolites in soybeans. In this report we compared the content of secondary metabolites between genetically modified (GM) and non-GM soybeans.
Six cultivars/lines of GM and six cultivars/lines of non-GM soybeans were extracted with methanol. Each extract was partitioned with aqueous methanol and hexane and the aqueous methanol fraction was partially purified by HP-20 and LH-20 column chromatography to afford crude soyasaponin and isoflavone fractions. The main A-type soyasaponin, acetylsoyasaponin A1 (AcA1), and the main B-type soyasaponins, soyasaponins I and II (I and II), in the crude fractions were identified by LC/MS analyses with authentic samples. The main isoflavones, daidzin, genistin, daidzein and genistein (DI, GI, DE and GE), in the crude fractions were identified by LC photo-diode array analyses with authentic samples.
The contents of AcA1, I and II in the crude soyasaponin fractions and those of DI, GI, DE and GE in the crude isoflavone fractions were analyzed by reversed-phase HPLC. The average contents (mg/100 g) of AcA1, I , II and total of B-type soyasaponins in GM soybeans were 36.4±24.2, 51.2±11.8, 26.4±7.6 and 77.7±18.5, respectively, and those in non-GM ones were 22.3±14.7, 46.3±17.8, 19.8±9.1 and 65.9±26.9, respectively. The average contents (mg/100 g) of DI, GI, DE, GE and total isoflavones in GM soybeans were 93.1±15.5, 121.8±19.4, 0.073±0.178, 0.320±0.082 and 215.3±33.3, respectively, and those in non-GM ones were 78.8±34.6, 106.7±28.3, 2.206±4.468, 0.822±0.754 and 188.5±26.7, respectively. There were no statistically significant differences in soyasaponin and isoflavone contents between GM and non-GM soybeans. Therefore, it was estimated that the GM soybeans are equivalent to the non-GM ones in terms of the composition of the main secondary metabolites.View full abstractDownload PDF (789K)
Notes
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Takumi AKIYAMA, Michiko YAMANAKA, Yukiko DATE, Hiroki KUBOTA, Megumi H ...2002 Volume 43 Issue 6 Pages 348-351
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA sensitive method for detecting bromate in bread by ion chromatography with inductively-coupled plasma mass spectrometry (IC/ICP-MS) was developed. Bromate was extracted from bread with water. The clean-up procedure included a 0.2 μm filter, a C18 cartridge for defatting, a silver cartridge to remove halogen anions, a centrifugal ultrafiltration unit to remove proteins, and a cation-exchange cartridge to remove silver ions. A 500 μL sample solution was applied to IC/ICP-MS. The detection limit and the quantitation limit of bromate in the solution were 0.3 ng/mL and 1.0 ng/mL, expressed as HBrO3, respectively, which corresponded to 2 ng/g and 5 ng/g, respectively, in bread. Recovery of bromate was about 90%, and the CV was about 2%. Based on the detection limit in solution and recovery from bread, the detection limit of bromate in bread was estimated to be 2 ng/g.View full abstractDownload PDF (137K) -
Makoto CHINO, Kyoko SATO, Takeshi YAMAZAKI, Tamio MAITANI2002 Volume 43 Issue 6 Pages 352-355
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSHokosshi extract is obtained by ethanol extraction from the seeds of hokosshi (Psoralea corylifolia), which is used as a Chinese medicine. The constituents of hokosshi extract were analyzed. The main constituent was isolated using column chromatography, and identified as bakuchiol by TLC, LC/MS and NMR. Bavachinin A was also detected. In order to prepare a marker substance for hokosshi extract, bakuchiol was isolated from seeds of hokosshi using Sep-Pak cartridges. An analytical method for hokosshi extract in foods based on detection of bakuchiol was developed. Bakuchiol was extracted from food with 60 vol% ethanol. The extract was cleaned up using a Sep-Pak plus C18 cartridge, and bakuchiol was determined by HPLC. Seasoning and juice were spiked with hokosshi extract at 500 μg/g and analyzed by the proposed method. The recoveries of bakuchiol were 72∼99%. The detection limit for the assay was 25 μg/g.View full abstractDownload PDF (403K) -
Maki KOBAYASHI, Toshihiro NAGAYAMA, Ichiro TAKANO, Yasuhiro TAMURA, Yu ...2002 Volume 43 Issue 6 Pages 356-361
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA simplified HPLC determination method for maleic hydrazide in agricultural products was developed, and commercial agricultural crops were investigated.
The homogenate of agricultural products was extracted with water. The crude extract was purified on an ACCUCAT Bond Elut® extraction cartridge using water. Maleic hydrazide was analyzed by HPLC with UV detection (303 nm). The HPLC separation was performed on a ZORBAX SB-Aq column with acetonitrile-water-phosphoric acid (5 : 95 : 0.01) as the mobile phase.
Recoveries of maleic hydrazide from 15 agricultural products fortified at 1.0 and 10 μg/g were in the ranges of 92.6∼104.9% and 94.2∼101.3%, respectively. The limit of detection was 0.5 μg/g in samples. The proposed method was applied to the determination of 242 commercial vegetables and fruits. Maleic hydrazide was detected in 2 samples of imported onion at the levels of 4.9 and 7.2 μg/g.View full abstractDownload PDF (619K) -
Yasuhiro TAMURA, Toshihiro NAGAYAMA, Ichiro TAKANO, Maki KOBAYASHI, Sa ...2002 Volume 43 Issue 6 Pages 362-365
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSAn unknown peak was detected in a GC chromatogram of many kiwi fruit extracts during analysis for pesticide residues. It was identified by GC/MS as diphenyl 2-ethylhexyl phosphate (DPEHP), used as a plasticizer and flame retardant. The concentration of DPEHP was investigated in 15 samples of kiwi fruit, and it was detected at between 0.02 and 0.14 μg/g in 10 of the samples. It might be due to migration of DPEHP into the fruit from the printed portion of the polyethylene terephthalate (PET) package.View full abstractDownload PDF (507K) -
Kumiko SASAKI, Takashi TATSUNO, Takakazu NOMURA, Tsuyoshi IMAZAWA, Osa ...2002 Volume 43 Issue 6 Pages 366-370
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA performance study of an analytical method of ethoxyquin (ET) in apples and pears was conducted. In the proposed method, the sample was homogenized with thiourea and ET was extracted with acetone instead of hexane used in the official analytical method for ET, in order to improve the extraction efficiency. Furthermore, dibutyl hydroxytoluene was added in the test solution to prevent the decomposition of ET. For evaluation of the method, ET spiked into apples and pears at the level of 0.2 μg/g was determined in replicate in six laboratories. Mean recoveries from apple, pear and Japanese pear were 85.3, 83.0 and 83.9%, respectively. Repeatability relative standard deviation values were 3.8∼4.7% and reproducibility relative standard deviation values were 7.8∼11.3%. The detection limits were 0.001∼0.025 μg/g in the six laboratories; this value may reflect instrument performance. ET spiked into apples and pears at the level of 0.2 μg/g was detected by both LC/MS and GC/MS.View full abstractDownload PDF (447K) -
Satoru NEMOTO, Satoshi TAKATSUKI, Kumiko SASAKI, Tamio MAITANI2002 Volume 43 Issue 6 Pages 371-376
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA method was developed for the determination of trace amounts of acrylamide (AA) in foods. The method includes the addition of 13C-labeled acrylamide-1-13C (AA-1-13C) as an internal standard, extraction with water, bromination, clean-up with a Florisil cartridge column, dehydrobromination and GC/MS analysis in the selected ion monitoring (SIM) mode. Bromination of AA to 2,3-dibromopropionamide (2,3-DBPA) was done using potassium bromide and potassium bromate under an acidic condition. 2,3-DBPA was converted to 2-bromopropenamide (2-BPA) by dehydrobromination with triethylamine before GC/MS analysis. The recoveries of AA from spiked potato chips, corn snack, pretzel and roasted tea were 97-105%, and their relative standard deviations were 0.8-3.9%. The detection limit of AA in foods was 9 ng/g. The method was applied to thirty-one foods purchased from retail markets. AA was found in potato chips at the level of 466-3,340 ng/g, and in other foods at the level of ND-520 ng/g.View full abstractDownload PDF (196K)
Reports
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Yukari TSUMURA, Akiko KAIHARA, Susumu ISHIMITSU, Kimihiko YOSHII, Yasu ...2002 Volume 43 Issue 6 Pages 377-384
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSPlasticizers in cap-sealing for bottled foods were analyzed. Twenty-three domestic samples and 80 imported samples, a total of 103 samples, were tested. Among them, 93 contained chloride, and 62 contained di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate, O-acetyl tributyl citrate, diacetyllauroyl glycerol, di(2-ethylhexyl) adipate, diisononyl phthalate or dicyclohexyl phthalate. Twelve samples with DEHP-containing caps were further tested for plasticizer levels in the foods. Higher DEHP was detected in oily and fluid food specimens. However, the intake of plasticizers calculated based on usual food consumption did not exceed the tolerable daily intake level in any of the cases. A food sample containing the highest level of DEHP was stored under various conditions, and DEHP that migrated from the cap-sealing into the food was determined. Shaking the bottles increased migration of DEHP into foods.View full abstractDownload PDF (582K) -
Yoko KAWASHIMA, Yuji NAGASHIMA, Kazuo SHIOMI2002 Volume 43 Issue 6 Pages 385-388
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSSalivary glands from 29 species of marine carnivorous gastropods in nine families were examined for lethal activity against mice and tetramine content. Mouse lethality was assayed by intravenous injection of buffer extracts into mice, and was detected in 14 species. Heat-stability tests confirmed that toxins in four species were thermolabile, while those in eight species were thermostable. Based on the tetramine contents determined by the colorimetric method using methanolic extracts, the thermostable toxins in seven species (Neptunea eulimatalamellosa, N. vinosa, N. arthritica, N. bulbacea, N. intersculpta f. pribiloffensis, N. intersculpta f. frater pilsbry and Hemifusus tuba) were considered to be tetramine contained at high levels (more than 900 μg/g salivary gland), but that in one species (Buccinum opisthoplectum) appeared to be a low-molecular-weight compound differing from tetramine. It is interesting that one (Hemifusus tuba) of the seven species containing high amounts of tetramine belongs to the family Melongenidae, although the other six Neptunea species are members of the family Buccinidae, as expected from previous studies.View full abstractDownload PDF (391K) -
Masahiro OKIHASHI, Yoko KITAGAWA, Kazuhiko AKUTSU, Hirotaka OBANA, Shi ...2002 Volume 43 Issue 6 Pages 389-393
Published: December 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSResidues of 17 pesticides in agricultural products were determined by LC/MS with an atmospheric pressure chemical ionization (APCI) interface in both positive and negative ion modes. Pesticides were extracted with acetonitrile, and the extracts were cleaned-up with a primary and secondary amine (PSA) mini-column eluted with acetone-hexane (1 : 1). Rice, orange and potato were spiked with the 17 pesticides at 0.1 μg/g and analyzed by the proposed method. The average recoveries of these pesticides usually ranged from 70 to 98% and the relative standard deviations were usually around 10%. These results suggested that LC/MS with APCI could be used to determine the residue levels of the 17 pesticides in these crops.View full abstractDownload PDF (177K)
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