All issues
Volume 29 (1988)
- Issue 6 Pages 385-
- Issue 5 Pages 297-
- Issue 4 Pages 227-
- Issue 3 Pages 175-
- Issue 2 Pages 115-
- Issue 1 Pages 1-
Volume 29, Issue 4
Displaying 1-8 of 8 articles from this issue
- |<
- <
- 1
- >
- >|
-
Fumio MIYAMOTO, Masanobu SAEKI, Motoo HARADA1988 Volume 29 Issue 4 Pages 227-234_1
Published: August 05, 1988
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSAn ion chromatographic (IC) method was developed for the determination of sulfur dioxide in foods. Sulfur dioxide was separated from a food sample by addition of acid and heating, and carried into a trapping solution by bubbling. Conditions for separation and trapping of sulfur dioxide were as follows: sample, 1-5g; acid, 40ml of 20% phosphoric acid deaerated with nitrogen for 10min; heating temp., 90°C; bubbling gas, nitrogen; flow rate, 800ml/min; bubbling time, 40min; trapping solution, 10ml of 1% triethanolamine solution. After bubbling, the trapping solution was subjected to IC. Sulfite was separated on an anionic separator column, “SAX-1” with 3.5mM Na2CO3/4.0mM NaHCO3 as the eluent and quantitated by the use of a conductivity detector.
In the determination of sulfur dioxide in foods by IC, nitrite ion and volatile aldehydes interfered. Thus, 1ml of 1% ammonium sulfamate solution was added the sample to eliminate nitrite and 5ml of 40% phosphoric acid containing 1% 2, 4-dinitrophenylhydrazine was placed between the trapping solution and the cooling condenser to eliminate aldehydes.
The recoveries of sulfur dioxide added to water and 6 foods at levels of 10 and 100μg/g were 87.8-109.0% and, 97.3-104.7%, respectively. The detection limit was 0.2μg/g in the case of a 5g sample size.
The proposed method, gas chromatography after separation and trapping by bubbling (bubbling-GC method) and the modified Rankine colorimetric method (MR method) were all applied to the determination of sulfur dioxide in commercial foods and the results were compared. The values of residual sulfur dioxide obtained from the foods treated with sulfite by all three methods were in good agreement. The values of naturally occurring sulfur dioxide obtained from the foods containing sulfur compounds without sulfite treatment by the proposed method and the bubbling-GC method were in good agreement, although those obtained by the MR method were higher.View full abstractDownload PDF (799K) -
Chiaki MURAKAMI, Takenori MARUYAMA, Isao NIIYA1988 Volume 29 Issue 4 Pages 235-239_1
Published: August 05, 1988
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA sensitive and rapid method for the determination of monoglycerides in foods by high performance liquid chromatography (HPLC) was developed. Monoglycerides in foods were derivatized with 3, 5-dinitrobenzoyl chloride (DNBC) without extraction. The reaction products were dissolved in a mixture of tetrahydrofuran and acetonitrile (1:1). A portion of this solution was injected on to a Unisil Q 5C8 column, and eluted with the mixture of acetonitrile and water (82.5:17.5) as the mobile phase. Detection was done with a UV detector set at 230nm. Monoglycerides in various foods could be selectively detected without interference on the HPLC. Peaks of monoglycerides having C14, C16, C18, C20, C22, C18:1 and C18:2 could be well separated.
The recoveries of monoglycerides added to shortening, margarine, mayonnaise, ice cream and coffee whitener at the level of 0.10% were more than 97%. The detection limits were 10.0μg/g for each monoglyceride. The proposed method for determination of the content and composition of monoglycerides in foods is suitable for routine work.View full abstractDownload PDF (518K) -
Yumiko NAKAMURA, Yasuhide TONOGAI, Yukari HASEGAWA, Yoshio ITO1988 Volume 29 Issue 4 Pages 240-248_1
Published: August 05, 1988
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSThe metabolism of alginic acid, sodium alginate, potassium alginate and calcium alginate, and their effect on the serum concentrations of Na, K and Ca in the rat were investigated by single-dose oral administration. Rats were orally given 90.4mg/kg (50 times of the daily intake of alginates of Japanese) of alginic acid, sodium alginate, potassium alginate or calcium alginate as a solution or suspension in water. No significant differences were observed in fecal excretion or the pattern of contents of alginates in the gastrointestinal tract as a function of time: 1) 72.7-79.3% of the administered alginates were excreted into feces within 3 days; 2) administered alginates remained in the stomach for 2 hours, then gradually moved to the small intestine after 4 hours and to the large intestine after 8 hours, and most of the alginates remained in the large intestine after 24 hours; 3) there were no significant differences in the serum concentrations of Na, K and Ca caused by the administration of alginates.View full abstractDownload PDF (950K) -
Koichiro YOSHIDA, Shinji MIYAKOSHI, Takayoshi HASEGAWA1988 Volume 29 Issue 4 Pages 249-255_1
Published: August 05, 1988
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA precise and sensitive analytical method was developed for the determination of heavy metals in food.
Diisobutyl ketone (DIBK), which is far less soluble in water compared to methyl isobutyl ketone or n-butyl acetate, was used with sodium diethyldithiocarbamate (DDTC) in the solvent extraction separation-flame atomic absorption spectrometry system. Cadmium, nickel, cobalt, lead and copper in alkaline solution (pH 13) could be extracted with DDTC into DIBK without interference from iron and manganese.
The proposed method was satisfactorily applied to the analysis of the environmental reference materials (pepperbush, chlorella and mussel) and some foods. The recoveries of these metals from foods were 95.3-102.6% and the relative standard deviations were 0.2-3.2%. Practical detection limits were generally 0.001μg/g for cadmium, 0.002μg/g for copper and 0.01μg/g for nickel, cobalt and lead.View full abstractDownload PDF (733K) -
Kazunori YAMAMOTO, Takahisa KAMIYA, Michihiko KOMURO, Shigeko KAKEFUDA ...1988 Volume 29 Issue 4 Pages 256-261_1
Published: August 05, 1988
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSSulfite reducibility of Clostridia isolated recently from flat sour spoiled canned “Shiruko” kept not in a vending machine was different from that of the strains which were isolated from the same spoiled canned drinks by Nakayama et al., and also group B strains isolated by Matsuda et al.
Since this sulfite reducibility is one of the important properties used to detect and identify the organisms causing flat sour spoilage of foods, the effect of sulfite on the growth of the isolates was examined using Clostridium thermoaceticum DSM 521 and ATCC 31490 as controls. It was shown that the growth of the isolates were inhibited markedly after 2 weeks of incubation at 55°C in the medium containing usual concentrations of sulfite (0.05-0.10%). This result suggests that the concentration of sulfite should be reduced to 0.03% to test the sulfite reducibility of flat sour spoilage organisms so that even organisms relatively sensitive to sulfite can grow without any inhibition.
As to the heat resistance, D121 and z were 44.7min at 14.0°C in the isolate, and 21.0min at 14.3°C in C. thermoaceticum DSM 521, respectively. By autoclaving at 121°C, 0.21% of the spores of the former survived after 120min, and 0.14% of that of the latter survived after 60min. Under the conditions of sterilization for 30min at 121°C, the rate of flat sour spoilage of artificially contaminated canned “Shiruko” with the isolate was 40%, after incubation for a week at 55°C.View full abstractDownload PDF (571K) -
Kojun TSUNODA, Noriko INOUE, Hiroko IWASAKI, Masato AKIYA, Akihisa HAS ...1988 Volume 29 Issue 4 Pages 262-266_1
Published: August 05, 1988
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA simple and sensitive method was developed for determination of nicotinic acid (NA) and nicotinamide (NAA) in foods. NA and NAA were extracted with methanol from meat after addition of a small amount of phosphoric acid. After filtration, NA and NAA in the extract were determined by high performance liquid chromatography (HPLC) with a UV detector at 261nm. Standard solutions of NA and NAA were prepared with a mixture of 0.2% sodium chloride-1% ammonium acetate solution: methanol (1:4). The HPLC system adopted was ion-pair chromatography in the reverse-phase mode on a 5cm short column (C18) with sodium dodecyl sulfate as a counter ion. Recoveries of NA and NAA added to beef, pork and tuna were more than 97%, and the detection limit was about 0.1mg% in samples.
During storage, NAA in meat and fish appeared to be changed to NA concomitantly with growth of bacteria, and the change was confirmed to be caused by bacteria rather than by any enzyme in the meat. NA was detected in most commercial meat and fish samples tested.View full abstractDownload PDF (506K) -
Eiko AMAKAWA, Kazuo OHNISHI, Motohiro NISHIJIMA, Senzo SAKAI1988 Volume 29 Issue 4 Pages 267-272_1
Published: August 05, 1988
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSA liquid chromatographic method was established for the determination of citric, tartaric, gluconic, malic, succinic, lactic, fumaric, acetic, adipic and propionic acids in foods.
A sample was homogenized in water. The homogenate was adjusted pH 9-10 then warmed for 15min at 80°C. After filtration, the extracted solution was poured onto a column of DEAE-Sephadex previously treated with 0.5N boric acid. The column was washed with water. The organic acids were eluted with 0.1% methyl red in ethanol-0.1N hydrochloric acid (0.1:500). The red portion of eluate was collected. The eluate was concentrated after neutralization with 10% sodium carbonate solution, if necessary. The organic acids in the eluate were separated on a Shodex lonpak KC811 column at 55°C.
Recoveries were 87.5-102% and coefficients of variation were 1.74-4.73%. This method was applied to determination of the organic acids in foods.View full abstractDownload PDF (601K) -
Takiko SUGITA (nee INOUE), Hajimu ISHIWATA, Kunitoshi YOSHIHIRA1988 Volume 29 Issue 4 Pages 273-279_1
Published: August 05, 1988
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSTwo methods for the determination of formaldehyde in migration solutions obtained from tableware made of thermosetting resins, that using acetylacetone (AA) and that using 4-amino-3-hydrazino-5-mercapto-1, 2, 4-triazole (AHMT), were compared. The calibration curve obtained by the AA method was y=0.132x-0.004, r=1.0000, and that obtained by the AHMT method was y=0.282x-0.005, r=0.9998, where y=optical density, x=concentration of formaldehyde (ppm) and r=correlation coefficient. These results indicated that the sensitivity of the AHMT method was 2.1 times higher than that of the AA method. The responses of acetaldehyde, propionaldehyde, n-butyraldehyde and acrolein in the AHMT method was 10 to 100 times higher than those in the AA method. No effect of coexisting urea, phenol or melamine up to 100ppm was observed in either method. The AHMT method was affected by temperature during standing for 20min and by the solvent of the formaldehyde, but both effects, temperature and solvent, were correctable by performing the determination under the same conditions with a standard solution of formaldehyde. In the migration test of formaldehyde from melamine ware using 4% acetic acid at 80°C and 95°C, no difference was found between the results determined by the AHMT method and by the AA method.View full abstractDownload PDF (792K)
- |<
- <
- 1
- >
- >|