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Volume 37 (1996)
- Issue 6 Pages 343-
- Issue 5 Pages 247-
- Issue 4 Pages 165-
- Issue 3 Pages 135-
- Issue 2 Pages 65-
- Issue 1 Pages 1-
Volume 37, Issue 2
Displaying 1-13 of 13 articles from this issue
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Motoichi MIYAZAKI, Atsushi YAMAMOTO1996 Volume 37 Issue 2 Pages 65-71
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
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Mutsuko MATSUZAWA, Hideo KAWAI1996 Volume 37 Issue 2 Pages 72-76_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA simple and rapid method was developed for quantitative analysis of choline in food by HPLC with an electrochemical detector. The hydrolysis of combined forms of choline in food into the free form was performed with hydrochloric acid.
The calibration plot for choline was linear in the range of 0.004-2.00nmol and the detection limit of choline was 4pmol (0.4ng) as choline chloride. The recovery of choline added to food was 93-105%. The average concentrations (mean±SD) of choline in spices and beans were 0.91±0.62mg/g and 1.71±0.34mg/g, respectively.View full abstractDownload PDF (476K) -
Keizo UMEGAKI, Takatoshi ESASHI, Masakatsu TEZUKA, Akiko ONO, Mituaki ...1996 Volume 37 Issue 2 Pages 77-82_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSTo develop a method for determination of tea catechins in food by HPLC with an electrochemical detector, we examined the responses of an electrochemical detector to tea catechins. Five catechins ((+)-catechin, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, (-)-epigallocatechin gallate) started to show a response at the applied potential of +400mV, and the maximum response was observed at about +800mV. The content of tea catechins in food is relatively high, and the sensitivity of the electrochemical detector to tea catechins was about one thousand times higher than that of the UV detector. Generally, an electrochemical detector responds to many substances as the applied potential is increased. We concluded that for the analysis of tea catechins in foods a suitable applied potential of the electrochemical detector is +500-+600mV. The detection limit for the tea catechins was about 0.2pmol (40pmol/ml) under the conditions used. When an extract from canned green tea was examined, gallic acid, gallocatechin and gallocatechin gallate were selectively detected in addition to the five catechins indicated above. Methylxanthins and vitamin C, which are often found in large amounts in green tea, did not interfere with determination of the tea catechins. These results indicated that the HPLC-electrochemical detector method is highly selective and appropriate for the determination of tea catechins in food.View full abstractDownload PDF (705K) -
Hajimu ISHIWATA, Yuiko TAKEDA, Yoko KAWASAKI, Ryo YOSHIDA, Takiko SUGI ...1996 Volume 37 Issue 2 Pages 83-90_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA survey of the concentration of carbon monoxide (CO) in flesh from a variety of fish was conducted to see whether fish which had been exposed to CO gas could be detected. CO in fish flesh was obtained by head-space gas chromatography and determined after conversion of CO to methane with a methanizer. Concentrations of CO ranged from 3 to 12μg/kg fish flesh, showing a narrow range in each species of fish except tilapia (Tilapia mossambica). CO was high in the red-flesh fish and low in the white-flesh fish. CO in sliced tilapia (a species of white-flesh fish), however, ranged from 7 to 957μg/kg. In tilapia, a high concentration of CO was observed in a sample in which the blood-colored parts of the slice were bright red, whereas the CO concentration was low in a sample in which the blood-colored parts were dark brown.
The CO concentration in sliced tilapia containing 8μg CO/kg increased to 234μg/kg when the slice was exposed to CO gas. The blood-colored parts of the slice became bright red after the exposure. CO in the homogenate prepared from the CO-exposed sample decreased to less than 50μg/kg within 4 days on storage in a refrigerator (5°C). The concentration of CO in the control increased slightly during this period. Among 19 commercial samples of tilapia, CO slightly increased in 5 samples containing about 10μg CO/kg and decreased in 14 samples containing more than 50μg CO/kg when the homogenate was kept at 5°C for 2 days. The blood-colored parts of the former group containing lower concentrations of CO were dark brown and those of the latter group containing higher concentrations of CO were bright red. The latter group of tilapia was suspected to have been exposed to CO gas.View full abstractDownload PDF (2164K) -
Takako MORIYASU, Mitsuo NAKAZATO, Chigusa KOBAYASHI, Yoko KIKUCHI, Kum ...1996 Volume 37 Issue 2 Pages 91-96_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSMethod for the determination of acesulfame K (AK), saccharin (SA) and aspartame (APM) in various foods was investigated. Chopped or homogenized samples were packed with 0.01N hydrochloric acid containing 10% sodium chloride into cellulose tubing and dialyzed against 0.01N hydrochloric acid for 24-48 hours. For the detection of AK and SA, the dialyzate was analysed directly by HPLC on a Cosmosil 5NH2 column using a mobile phase of methanol-1% phosphoric acid (6:4) with detection at 230nm. For APM, the dialyzate was passed through a Sep-pak Vac C18 cartridge. The cartridge was washed with water and a mixture of methanol-water (2:8). APM was eluted with a mixture of methanol-1% phosphoric acid (3:7). It was separated on a Cosmosil 5C18-AR column using a mobile phase of methanol-0.02M phosphate buffer pH 4.0 (1:3) with detection at 210nm.
The recoveries of AK, SA and APM added to various foods were 94.3-100.4%, 80.4-99.6% and 90.8-101.7%, respectively. The detection limits of AK and APM were 10μg/g and that of SA was 5μg/g.View full abstractDownload PDF (717K) -
Takahiro ODA, Hiroshi HIWAKI1996 Volume 37 Issue 2 Pages 97-103_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSFor estimation of antibiotic residues in food, heat treatments of extract solutions spiked with antibiotics were performed under 4 conditions: heated in boiling water, heated in an autoclave (121°C, 15min), heated in an autoclave under an acid (pH 2) condition, heated in an autoclave under an alkaline (pH 12.5) condition.
Heat stabilities of 24 antibiotics were evaluated as the ratio of the reduction of inhibition zone diameter in the paper disk method after/before heat treatments. Each antibiotic exhibited a characteristic heat stability pattern. Therefore, heat treatments of food extract solutions containing unknown antibiotics are a useful approach for estimation of antibiotic residues.View full abstractDownload PDF (664K) -
Kyoji YOSHINO, Yoshiyuki NAKAMURA, Hirotoshi IKEYA, Tomomi SEI, Aya IN ...1996 Volume 37 Issue 2 Pages 104-108_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSAntimicrobial activities of tea extracts on the cariogenic bacterium, Streptococcus mutans, were studied. Extracts of green and black tea leaves effectively suppressed the growth of S. mutans as compared with those of oolong and Pu-erh tea leaves. Ethyl acetate and n-butanol extracts of both green and black tea leaves and the non-dialyzable fraction of the water-soluble fraction of black tea leaves showed strong antimicrobial activities on S. mutans. Catechins were found in the ethyl acetate and n-butanol extracts of green tea leaves, while catechins, theaflavins, and gallic acid were found in these extracts of black tea leaves. Polyphenols and esterified gallic acid were found in the nondialyzable fraction of black tea leaves.View full abstractDownload PDF (631K) -
Fumiko NOMURA, Minoru OHASHI, Megumi OTSUKA, Osao ADACHI, Nobuhiko ARA ...1996 Volume 37 Issue 2 Pages 109-113_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA modified extraction method for determination of histamine in fish by using an oxygen sensor was examined. Histamine in canned and raw tuna was extracted with methanol, then the solution was evaporated and the residue was dissolved in phosphate buffer (0.1M, pH 7.6). There was a high correlation between histamine contents determined by the oxygen sensor and the AOAC methods.
To simplify the procedure, histamine in canned tuna was extracted by adding phosphate buffer and heating at 100°C in a water bath for 15min. There was a high correlation between the contents of histamine extracted with phosphate buffer and determined by the oxygen sensor method and those of histamine extracted with methanol and determined by the AOAC method. This heating extraction procedure in buffer is simple, rapid and practical for consecutive assay of many samples.View full abstractDownload PDF (621K) -
Kazuo EGOSHI, Terumi OKA, Kouji ABO1996 Volume 37 Issue 2 Pages 114-118_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSAdsorption of IQ, Trp-P-1 and Trp-P-2 on insoluble dietary fiber, cellulose, CM-cellulose, xylan, chitin, collagen and acid detergent fiber (ADF: containing cellulose and lignin) from nine species of edible plants was measured by HPLC. Cellulose and ADF from burdock, dropwort and bamboo shoot showed high adsorptive power for IQ, Trp-P-1 and Trp-P-2. The results suggest that consumption of edible plants containing cellulose would help to prevent the internal absorption of heterocyclic amines formed in cooked fish and meats.View full abstractDownload PDF (650K) -
Yukari TSUMURA, Yunosuke GOTO, Nozomi MUNAKATA, Yumiko NAKAMURA, Yasuh ...1996 Volume 37 Issue 2 Pages 119-122_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSFenarimol and lenacil in agricultural products were determined using the method previously reported by the authors [Shokuhin Eiseigaku Zasshi 36 (5), 613-621 (1995)]. Ten grams of grain or 20g of vegetable or fruit was homogenized with acetone followed by extraction with ethyl acetate, and the extract was evaporated. In the case of grains, fat or oil was removed from the extract by n-hexane-acetonitrile partitioning. Then the extract was purified by Florisil column chromatography and concentrated to 5ml. The concentrations of pesticides were determined by FTD-GC. The recoveries of fenarimol and lenacil spiked in ten kinds of agricultural products at the level of 0.1ppm (vegetables and fruits) or 0.2ppm (grains) were 72.8-92.2%. The detection limit was 0.01ppm for each pesticide.View full abstractDownload PDF (311K) -
Hisashi MATSUMOTO, Yasuyuki MURAKAMI, Katsuyoshi KUWABARA, Hiroshi MUR ...1996 Volume 37 Issue 2 Pages 123-126_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
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Toshihiro NAGAYAMA, Maki KOBAYASHI, Masako Ito, Hiroko SHIODA, Toshio ...1996 Volume 37 Issue 2 Pages 127-134_1
Published: April 05, 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESS -
1996 Volume 37 Issue 2 Pages J136-9
Published: 1996
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSDownload PDF (229K)
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