Japanese Journal of Food Chemistry and Safety
Online ISSN : 2189-6445
Print ISSN : 1341-2094
ISSN-L : 1341-2094
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Showing 1-7 articles out of 7 articles from the selected issue
Regular articles
  • Eri Nakamura, Mizuki Takeda, Isao Tomita, Toshiki Matsuura
    2021 Volume 28 Issue 1 Pages 1-8
    Published: 2021
    Released: April 20, 2021
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    Green tea contains catechins, dietary fiber, and many other ingredients with health benefits. Sencha (green tea) contains watersoluble components, such as catechins and amino acids, while matcha contains not only catechins and amino acids, but also waterinsoluble dietary fiber. In this study, we examined whether the dietary fiber in matcha is involved in inhibiting lipid absorption by measuring the lipid adsorption rate of matcha, the inhibition of pancreatic lipase activity, and the inhibition of lipid absorption in rats. The lipid adsorption rate of a 10% matcha suspension was about 25%, whereas the lipid adsorption rate of a 6.4% cellulose suspension of matcha, which contained the equivalent amount of insoluble dietary fiber, was about 4%. Furthermore, the effect of matcha or cellulose on lipid digestion and absorption was measured in rats with gastric catheterization and subclavian vein catheterization. The results showed that matcha had a suppressive effect on lipid digestion and absorption. These results suggest that the lipid-suppressing effect of matcha is due to the action of catechins and dietary fibers other than cellulose in matcha, and that cellulose has little effect.
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  • Yusuke Okamoto, Kyohei Higashi, Toshihiko Toida
    2021 Volume 28 Issue 1 Pages 9-15
    Published: 2021
    Released: April 20, 2021
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    An intact proteoglycan was extracted from salmon (Oncorhynchus keta) nasal cartilage containing type II collagen and prepared using a novel extraction procedure in water containing a sugar fatty acid ester as an edible detergent. This isolation step suppressed the degradation of the proteoglycan and simultaneously afforded a proteoglycan-type II collagen matrix. The extracted proteoglycan was purified, and its properties were compared with those prepared via different extraction procedures using gel permeation chromatography and polyacrylamide gel electrophoresis. Furthermore, the interaction between the purified proteoglycan and human L-selectin was analyzed using a bio-layer interferometry biosensor assay; the proteoglycan demonstrated strong binding to L-selectin.
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  • Yutaka Abe, Miku Yamaguchi, Hiroyuki Ohno, Yohei Kataoka, Motoh Mutsug ...
    2021 Volume 28 Issue 1 Pages 16-22
    Published: 2021
    Released: April 20, 2021
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    We validated an alternative testing method for the determination of dibutyltin (DBT) compounds in food utensils, containers, and packaging products made from polyvinyl chloride using gas chromatograph-mass spectrometry with nitrogen (N2) as a carrier gas. The retention times, mass spectra, ion intensities, and signal-to-noise-ratios (S/N) of a DBT derivative were compared using both helium and N2 as the carrier gas. The retention times were almost equal under the same flow-rate condition, as were the mass spectra. In contrast, the ion intensity with the N2 carrier gas decreased to around 3/4, and the S/N decreased significantly to 1/10. This might be due to the increase in background noise level. We validated the performance in terms of a limit testing method that assess its suitability by comparing the peak area values of the DBT derivative in the test solution and a standard solution at a concentration corresponding with the acceptance criteria and a quantitative testing method with N2 carrier. All parameters corresponding to the trueness, repeatability, and reproducibility as intermediate precision, satisfied the target values in both cases, indicating that both approaches demonstrate good performance as a testing method.
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  • Akihiro Ikuno, Yu-ta Minamigawa, Shin-ichiro Takebayashi, Katsuzumi Ok ...
    2021 Volume 28 Issue 1 Pages 23-32
    Published: 2021
    Released: April 20, 2021
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    Many studies have shown that folate deficiency induces DNA hypomethylation and DNA damage. DNA hypomethylation is thought to occur during DNA replication through deficiency of the DNA methylation donor synthesized using folate. However, the relationship between DNA hypomethylation and DNA damage caused by folate deficiency is not well understood. Here, we analyzed DNA damage caused by folate deficiency during the cell cycle S phase in which DNA hypomethylation occurs. Using HeLa cells, we first detected accumulation of intranuclear γ-H2A.X, a DNA double strand break marker, by immunofluorescent staining. We found that DNA damage occurs primarily during S phase, and that folate deficiency enhanced S phase-dependent DNA damage. We also found that folate deficiency caused slowing of the DNA replication fork and a delay in the onset of middle-late S phase. Detailed analyses of DNA damage in S phase progression suggested that the folate deficiency-induced DNA damage increased in all stages of S phase, particularly in middle-late S phase cells. To examine the relationship between DNA damage and DNA hypomethylation, we analyzed the methylation state of the promoter region of the human LINE1 repetitive sequence, where heterochromatin is formed and replicated during middle to late S phase. We found that DNA methylation decreased by about 10% under the folate deficiency condition. Taken together, our results suggest that DNA hypomethylation is associated with DNA damage caused by folate deficiency.
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Research letters
  • Tomoaki Tsutsumi, Rika Adachi, Hiroshi Akiyama
    2021 Volume 28 Issue 1 Pages 33-38
    Published: 2021
    Released: April 20, 2021
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    The Helium (He) Saver injector can dramatically reduce consumption of He gas in GC-MS(/MS) analysis in comparison to a conventional split/splitless (SSL) injector using helium carrier gas. The He Saver injector was evaluated in comparison with SSL injector using organochlorine pesticides including their metabolites (10 analytes). The standard solutions (1 ng/mL and 100 ng/mL) of the analytes were analyzed 5 times each by GC-MS/MS using the two injectors. Retention times, peak shapes and peak areas of the analytes were compared between the two injectors. The retention times obtained by the He Saver injector were in good agreement with those obtained by the SSL injector. The selected reaction monitoring chromatograms from both the injectors showed no remarkable differences in peak profiles. The average peak areas using the He Saver injector were close to those obtained using the SSL injector (94-115% of the SSL injector). Although there were statistically significant differences of the peak areas in three of the ten analytes using a two-sided t-test (p<0.05), these differences were not considered to be important in a practical analysis. Peak area ratios for the analytes (qualifier ions/quantifier ions) using the He Saver injector were also close to those using the SSL injector (94- 104% of the SSL injector). Overall results indicate that the He Saver injector can be used for as an alternative for a conventional SSL injector and contribute to a reduction of helium consumption in GC-MS(/MS) analysis.
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  • Takehiko Tsuji, Yoshiaki Umemoto, Yushi Matuo
    2021 Volume 28 Issue 1 Pages 39-46
    Published: 2021
    Released: April 20, 2021
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    In this article, we emphasize that: (i) methylglyoxal (MGO) is mainly formed as a byproduct of glycolysis and, under physiological circumstances, detoxified by the glyoxalases (GLXase) and glutathione (GSH) systems; (ii) the imbalance between the formation of MGO and its detoxification is linked to the rapid reaction with guanidyl residue, forming MG-H1/CEA; (iii) the MGO modification/ glycation is subsequently leading to the vascular complications in diabetes.
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  • Chie Akaboshi, Tatsuya Sano, Yuichi Yoshida, Shigeki Hashiguchi, Takaa ...
    2021 Volume 28 Issue 1 Pages 47-53
    Published: 2021
    Released: April 20, 2021
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    Prefectural and municipal public health institutes have tested human samples, such as blood and urine, of patients with chemical food poisoning to analyze the harmful substances present in them. Because these samples may contain pathogens, guidelines for their treatment are required to prevent sample-mediated infections in microbiological laboratories. We developed a biosafety guideline for physical and chemical laboratories to establish biosafety strategies, wherein we suggested that the inspection status and sampleborne infection risk in the determination of infectious samples at each institute should be considered. Additionally, we listed the important elements to be considered while establishing the handling and management methods for preventing the accidental exposure to infectious samples while performing physical and chemical experiments. These elements assess the exposure risk of each process in the physical and chemical experiments, select the handling method according to the risk, provide the personnel with instructions on biosafety, consider the infection prevention measures, such as vaccination to the person in charge, supervise and record the performance of inspections, and establish the protocols for dealing with the accident. In this study, the handling and management methods at one institute could be established in accordance with this guideline. In the institute, wet human samples are decided to be treated as infectious samples based on standard precautions, while dry human samples can be treated in the same way as food and environmental samples. The guideline would be useful in treating infectious samples in physical and chemical laboratories.
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