Online ISSN : 1880-4500
Print ISSN : 1347-0485
ISSN-L : 1347-0485
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Original Paper
  • Fumiya Miyazaki, Kyohei Nomura, Fumihide Shiraishi
    2020 Volume 32 Issue 4 Pages 75-81
    Published: October 31, 2020
    Released: October 31, 2020

    To explore the possibility of aluminum (Al) materials as a support, titanium dioxide (TiO2) was immobilized on aluminum Al foil sheets and tubes and acetaldehyde (AA) and toluene were photocatalytically decomposed. The photocatalyst immobilized on the Al foil sheet provided the highest activity at a drying temperature of 400 °C. This is mainly due to a fact that organic compounds accumulated in an electric dryer hardly adsorb on a TiO2 film in the drying process. Both the photocatalysts immobilized on the Al foil sheet and tube quickly decomposed AA and toluene to below the measurement limits of a gas chromatograph (30 and 40 ppb, respectively). Moreover, simulations on the photocatalytic decomposition of AA indicated that in the 40 m3-room under a constant release of AA from the wall, the steady-state concentration of AA certainly becomes less than the indoor-air guideline of AA if twelve reaction tubes are used. In conclusion, the Al materials can effectively be used as a support of TiO2.

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  • Nguyen Huynh Phuong Uyen, Pham Thi Phuong Thao, Ryoko Asada, Kiyoshi ...
    2020 Volume 32 Issue 4 Pages 83-88
    Published: October 31, 2020
    Released: October 31, 2020

    The activities of three kinds of lipases, namely, Candida cylindracea (AYS Amano), Pseudomonas fluorescens (AK Amano), and Burkholderia cepacia LP-7 (PS Amano SD) were investigated in enzymatic hydrolysis of canola oil. Among the lipases, AYS Amano had the highest activity in the hydrolysis of canola oil, where 60% of triglyceride (TG) was hydrolyzed in 8 h at 40 °C. The TG was degraded rapidly in 2 h, where 50% of TG was hydrolyzed to diglyceride (DG), monoglyceride (MG), and fatty acid (FA). However, the rate of hydrolysis decreased after 2 h due to a reverse reaction. Lipase inactivation by gamma ray irradiation was also examined in absorbance dose range of 0.2-1.0 kGy. The results demonstrated that the inactivation of lipase in the aqueous phase was higher than that of powder in the solid state. Moreover, ionizing radiation treatment was effective for the inactivation of lipase in oil seeds, and this inactivation method can be used to stabilize oil for long-term storage.

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  • Susumu Hisamatsu, Kei Kan, Kasumi Okuoka, Fujio Baba, Akira Tani
    2020 Volume 32 Issue 4 Pages 89-96
    Published: October 31, 2020
    Released: October 31, 2020

    Wasabi (Eutrema japonicum (Miq.) Koidz.) was grown in a traditional cultivation field using spring water in Izu peninsula for 12 months. Four different shading nets were applied to the cultivation field to reduce sun light during the whole period. Among 4 nets, white-colored net transmitted photosynthetic active radiation (PAR) most abundantly (64%), whereas black-colored net did least abundantly (22%). Blue-colored and red-colored nets had similar values of PAR transmittance (58%). Transmittance of shortwave radiation including PAR and near infrared (NIR) was almost same among white-colored, blue-colored, and red-colored nets. As a result, temperature of black-painted brass boards placed horizontally was almost same under the three nets, suggesting that white-colored net can effectively reduce NIR and transmit PAR abundantly. Whole plant fresh weight and rhizome weight of wasabi were highest under white-colored nets. Pungent components such as allyl isothiocyanate were not significantly different among the four nets. Our result suggests that white-colored net can enhance wasabi growth compared with the other three nets, probably owing to abundant PAR and suppressed NIR reaching the plant surface.

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