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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 3
Displaying 1-13 of 13 articles from this issue
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Originals
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Tetsuya SHINDO, Hirofumi USHIYAMA, Kimiko KAN, Shin-ichi UEHARA, Kazuo ...2002 Volume 43 Issue 3 Pages 115-121
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSFour kinds of barbaloin (BA)-related compounds (A, B, C, D) in aloe drinks were isolated by using preparative HPLC. LC/MS analyses of these compounds showed the identical quasi-molecular ion peak at m/z 833 [M-H]-. The chemical structures were mainly determined by NMR, including 1H-1H two-dimensional correlation spectroscopy (COSY), nuclear Overhauser and exchange spectroscopy (NOESY), heteronuclear multiple quantum coherence (HMQC), and hetero-nuclear multiple-bond connectivity (HMBC) experiments. They were identified as BA-related compounds A (10R, 10''S), B (10S, 10''S), C (10S, 10''R), and D (10R, 10''R) coupled through a C-10 to C-7' linkage, and newly found in nature. These results suggested that BA is converted to dimers during storage of aloe drinks.View full abstractDownload PDF (545K) -
Tetsuya SHINDO, Hirofumi USHIYAMA, Kimiko KAN, Shin-ichi UEHARA, Kazuo ...2002 Volume 43 Issue 3 Pages 122-126
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSThe contents of barbaloin (BA), isoBA, aloin-dimers A, B, C, D and aloe-emodin (AE) in aloe drinks were investigated. BA and isoBA were detected in 30 of the 31 samples at the levels of 120∼570 μg/mL and 120∼580 μg/mL, respectively. Aloin-dimers A, B, C and D were detected in 8 of the 31 samples at the levels of 12∼38 μg/mL, 13∼39 μg/mL, 11∼36 μg/mL and 16∼69 μg/mL, respectively. AE was detected in all of the 31 samples at the levels of 0.03∼1.3 μg/mL.
When aloe drinks were stored for 4 weeks at 5°C after opening the bottle, decrease of BA and isoBA, and increase of AE and aloin-dimers A, B, C and D were observed in most cases. However, in a few aloe drinks, all of BA, isoBA, aloin-dimers A, B, C, D and AE decreased. In these drinks, the existence of aloin-trimer was elucidated by LC/MS analyses. These data suggested that BA in aloe drinks is converted to the dimer and then to the trimer during storage.View full abstractDownload PDF (484K) -
Kyoko TAKAHASHI, Yasuo TANAKA, Shiro HOSOI, Toshio HIDAKA, Susumu USUI2002 Volume 43 Issue 3 Pages 127-132
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA dual-column GC system equipped with MS and ECD, using two identical columns (HP-1701), one connected to the MS and one to the ECD, has been developed. The carrier gas flow rate was adjusted to give the same retention time of each peak in both columns. Unknown peaks were detected and identified in 7 samples of crops using this system. It was confirmed that the unknown peaks were 5 pesticides, i.e., bromopropylate and others. The recoveries and CV of bromopropylate from spinach and Komatsuna were good. The results of determination of bromopropylate by both MS and ECD were the same. Unknown chemicals can be easily identified using GC equipped with MS and ECD, and this system should be useful in the field of food hygiene.View full abstractDownload PDF (596K) -
Maki KOBAYASHI, Toshihiro NAGAYAMA, Ichiro TAKANO, Yasuhiro TAMURA, Na ...2002 Volume 43 Issue 3 Pages 133-143
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSWe investigated the determination of N-methylcarbamate pesticides and their metabolites in agricultural products by HPLC with post-column fluorescence detection after clean-up with an SPE cartridge.
The homogenate of agricultural products was extracted with acetone. The crude extract was partitioned between 5% sodium chloride solution and dichloromethane, and the dichloromethane layer was concentrated to dryness. The residue was dissolved with a mixture of acetone and n-hexane, and purified by using SupelcleanTM ENVITM-Carb SPE, Bond Elut® Extraction Cartridge PSA and SAX in series with a mixture of acetone and n-hexane. N-Methylcarbamate pesticide was analyzed by HPLC with post-column reaction and fluorescence detection. N-Methylcarbamate pesticide in citrus fruits and various kinds of agricultural products could be analyzed accurately by the presented method.
Recoveries of N-methylcarbamate pesticides added to several agricultural products at the level of 0.10 ppm were mostly in the range of 60∼110%. The limit of detection was 0.005 ppm.View full abstractDownload PDF (1065K) -
Tamiko HASHIMOTO, Sachio NISHIO, Naoyoshi NISHIBORI, Shinji YOSHIOKA, ...2002 Volume 43 Issue 3 Pages 144-147
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA new ion-pairing high-performance liquid chromatography (HPLC) method on a C30 column with a volatile mobile phase was developed to separate the gonyautoxin group (GTXs) from contaminants, allowing the utilization of liquid chromatography/mass spectrometry (LC/MS) with higher performance. A mobile phase consisting of 5 mmol/L heptafluorobutyric acid and 2% acetonitrile in 10 mmol/L ammonium acetate was adopted for separation of GTXs because the C30 column strongly retains GTXs under acidic conditions. The newly adopted method could efficiently separate GTXs from contaminants, especially in the toxic short-necked clam, whereas the routine HPLC so far used has poor resolution to separate GTXs from unknown interfering substances. In our method, GTXs were eluted in the order of GTX5, GTX3, GTX4, GTX2 and GTX1 from the C30 column, and were successfully determined by sonic spray ionization mass spectrometry (SSI-MS) with high sensitivity. This method is characterized by the combination of HPLC using a fluorescence detection system for PSP, and SSI-MS for measurement of the mass number.View full abstractDownload PDF (244K) -
Kiyoshi SEKITA, Takashi UMEMURA, Minoru SAITO, Yukio OGAWA, Katsunori ...2002 Volume 43 Issue 3 Pages 148-154
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA subchronic toxicity study on kooroo color was conducted using F344 rats of both genders. Kooroo color is an extract of yam root, Dioscorea matudai HAYATA, of which the major components are known to be flavonoid pigments. Use of kooroo as a food color is permitted by the Food Sanitation Law in Japan, but the chronic toxicity has not been evaluated in the literature. Rats were fed the product of kooroo color (PKC) at doses of 0.5%, 1.50%, and 5.0% in basal powder diet, while control groups received PKC-free basal diet, for ninety days. A vehicle control given propylene glycol (PG) alone, at the same dosage that the 5.0% group received, was included, because PKC used in this study contained ca. 80 percent PG, used as an extractant during the manufacturing processes. Daily observation of general behavior, and weekly measurement of body weight as well as food consumption were performed. Hematological, serum biochemical and anatomopathological examinations were conducted at the end of administration. No abnormalities ascribable to the treatment with PKC or PG were noted in any examination in this study. Hence, dietary intake of 5.0% of PKC, i.e., 2,993 mg/kg/day for males, and 3,376 mg/kg/day for females, as a mean daily intake for 90 days, had no observable adverse effect in F344 rats. Therefore, kooroo color has no significant general toxicity, and its toxicity, if any, is of a very low order.View full abstractDownload PDF (640K) -
Hiroshi FUJIKAWA, Satoshi MOROZUMI2002 Volume 43 Issue 3 Pages 155-159
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSNew estimation methods of bacterial cell concentration in samples by measurement of the increase in bacterial adenosine-triphosphate (ATP) content during incubation using a conventional firefly luminometer were established. When an Escherichia coli cell suspension was incubated in nutrient broth, the increase in the ATP content of the suspension during the incubation period followed a sigmoidal curve. The increase ratio of the ATP content of the suspension at a given period of incubation (5 hours in this study) to the initial ATP content was greater at higher initial cell concentrations. With this relationship, the initial cell concentration of a test suspension could be predicted from the measured ratio; this was called the end point method. On the other hand, the lag period in the ATP increase curve was longer at lower initial cell concentrations. A highly linear relationship was observed between the lag period and the logarithm of the initial cell concentrations. Based on this relationship, a delay method was developed for prediction. The two relationships were also observed for bacterial suspensions of Klebsiella sp., Staphylococcus aureus, Bacillus subtilis, and Pseudomonas sp. These results suggested that the two methods have the potential to estimate the bacterial cell concentration of a sample suspension.View full abstractDownload PDF (211K) -
Hiroshi FUJIKAWA, Akihiro IBE, Tomoaki WAUKE, Satoshi MOROZUMI, Haruhi ...2002 Volume 43 Issue 3 Pages 160-164
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSProduction of volatile substances from edible oils and their constituents by Penicillium corylophilum was studied to clarify the mechanism of flavor production from a non-stick oil by the organism in a rice cake system. First, edible oils from plant and animal origins were tested for flavor production. Among the oils tested, coconut oil was the only one from which the flavor was produced. Second, triacylglycerols consisting of fatty acids with various lengths of carbon chain (C6 to C13) were studied for flavor production. Among the triacylglycerols tested, flavors were produced from those consisting of fatty acids with carbon chains of C6 to C11. The flavors consisted of methylketones and secondary alcohols, whose carbon chains were one carbon shorter than the precursor fatty acid molecules of the triacylglycerols. Flavors similar to that from the non-stick oil were produced from tricaprylin (C8), trinonanoin (C9), and tridecanoin (C10) among the triacylglycerols tested. Formation of mould spores was more strongly suppressed by triacylglycerols with shorter chain fatty acids. Third, fatty acids with various lengths of carbon chain (C7 to C15) were studied for flavor production. Among the fatty acids tested, flavors were produced from decanoic (C10) and undecanoic (C11) acids only. The flavors also consisted of methylketones and secondary alcohols one carbon shorter than the precursor fatty acids. Fatty acids with short carbon chains (C7 to C9) completely inhibited the mould growth. Our study showed that the range of carbon chain length of fatty acids capable of the flavor production (C10 to C11) was narrower than that of triacylglycerols (C6 to C11). It was also found that the non-stick oil and coconut oil contain tricaprylin and tridecanoin as triacylglycerols and decanoic acid as fatty acid.View full abstractDownload PDF (133K) -
Kazuko AOKI, Seiichi UENO, Mutsuo ISHIZAKI2002 Volume 43 Issue 3 Pages 165-168
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA simple and convenient method for colorimetric determination of sulfite in foods based on its conversion to formaldehyde with sulfite oxidase and catalase was developed.
Sulfite in a sample was extracted with water and then diluted with methanol. One mL of sample solution containing about 5∼10 μg of sulfite was taken into a test tube with a ground-glass stopper, and 3 mL of 0.04 mol/L borate buffer (pH 8.7), 1 mL of 0.4% 3-methyl-2-benzothiazolinone hydrazone (MBTH) solution, 2,000 units of catalase solution and 1.0 units of sulfite oxidase were added. The mixture was incubated for 35 minutes at 37°C. Then 0.15 mL of 1 mol/L hydrochloric acid and 5 mL of 0.2% iron(III) nitrate solution were added. The reaction mixture was transferred to a measuring flask after standing for 5 minutes at room temperature, and diluted to 20 mL with methanol. The absorbance of this solution was measured using a spectrophotometer at the wavelength of 635 nm. The calibration curve prepared with sodium sulfite showed linearity between 0 to 16 μg/mL as sulfur dioxide.
The recoveries of sulfite in “Kanpyo” (dried gourd shavings) and “Konnyaku-seiko” (devil's-tongue fine powder) by the proposed method were 97∼104%, and the coefficients of variation were below 6%. The sulfite values in these foods determined by the proposed method were reasonably consistent with those obtained by the bubbling distillation-alkaline titration method.View full abstractDownload PDF (409K)
Notes
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Sadao WATANABE2002 Volume 43 Issue 3 Pages 169-172
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSA rapid analytical method for residues of the herbicide glufosinate [DL-homoalanin-4-yl(methyl)phosphinic acid] and its metabolite (MPPA: 3-methylphosphinicopropionic acid) in soybeans and corns was developed by improving the bulletin method. Fifty mL of solution extracted with water (corresponding to 2 g of the sample) was loaded on a column packed with 5 mL of anion exchange resin, and then the trapped glufosinate and MPPA were eluted with 40 mL of 50% acetic acid. After the derivatization of glufosinate and MPPA with trimethyl orthoacetate, the derivatives were purified and separated on a silica gel cartridge column. The determination of the derivatives was performed with a GC-FPD. The detection limits for glufosinate and MPPA were 0.01 μg/g and 0.005 μg/g, respectively. The recoveries of glufosinate from soybeans and corns were 86.3∼92.0%, and those of MPPA were 86.5∼95.2%.View full abstractDownload PDF (378K) -
Kaori TAKEKIDA, Yutaka KIKUCHI, Takeshi YAMAZAKI, Tomoshi KAKEYA, Kosu ...2002 Volume 43 Issue 3 Pages 173-177
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSWe developed a competitive enzyme-linked immunosorbent assay (ELISA) to detect prion protein contained in materials derived from cattle, aiming at establishing a method to detect abnormal prion protein (PrPSc) in food products. Rabbit polyclonal antibodies were raised against bovine prion peptides. Using these antibodies, we have established a competitive ELISA that is capable of detecting recombinant bovine prion protein (rBoPrP) in the range of 12 to 1,200 ng and we used it to determine prion protein contents in bovine cerebral cortex. This assay system was evaluated by spiking food products with various amounts of rBoPrP. The determination gave 2-fold higher values in minced meat homogenates and lower values in large intestine homogenates than the values expected from the spiked amounts. This assay provides a simple determination method of spiked rBoPrP, and therefore is expected to be useful for investigating sample pretreatment methods.View full abstractDownload PDF (502K)
Reports
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Katsuhiro AIKAWA, Hiroyuki MURAKAMI, Kyoko INOMATA, Tsutomu MARUYAMA, ...2002 Volume 43 Issue 3 Pages 178-184
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSBasal studies for the confirmation of sanitary rules in the kitchen were performed, focusing on preventing an outbreak of food poisoning due to eggs contaminated with Salmonella Enteritidis (SE), using hen and quail eggs. SE did not grow at 5°C but grew markedly at 25°C in eggs. The invasion and growth of SE were marked under very humid conditions regardless of whether the eggshell was damaged. The invasion of SE into egg also occurred when eggs were taken in and out of the refrigerator. Moreover, SE was spread immediately to all non-contaminated eggs when SE-contaminated eggs were cracked into a bowl with non-contaminated eggs. In homemade mayonnaise containing 15% vinegar, sterilization took several hours to occur. On a stainless-steel bowl, SE survived for 2 weeks or more. These findings suggest that it is necessary to pay attention to secondary contamination.View full abstractDownload PDF (565K) -
Isao SAITO, Eiji UENO, Harumi OSHIMA, Hiroshi MATSUMOTO2002 Volume 43 Issue 3 Pages 185-189
Published: June 25, 2002
Released on J-STAGE: April 30, 2009
JOURNAL FREE ACCESSThe levels of dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP), di-isononyl phthalate (DINP), di-(2-ethylhexyl) adipate (DEHA) and di-isononyl adipate (DINA) were determined in 50 processed foods (ham and sausage, fried dumpling and shao-mai, fish paste products, croquette and fried fish, bread, noodle, pickles, etc.). DBP, BBP, DEHP, DINP, DEHA, and DINA were contained at nd∼47.7, nd∼16.6, nd∼749, nd∼358, nd∼57.2 and nd∼20,200 ppb, respectively. High-level contamination of DINA was found in fish paste products, croquette and shao-mai, presumably because of migration from plasticized wrapping film using for food packaging. We studied the relationship between DINA migration from wrapped PVC film into fried croquette and its standing time after frying. When the croquette was wrapped immediately after frying, the migration from wrapping film into the croquette was highest (36,400 ng/g). On wrapping after standing for 5 min and 30 min, the migration level was reduced to 1/3.5 and 1/14 of the highest level, respectively.View full abstractDownload PDF (553K)
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