Chagyo Kenkyu Hokoku (Tea Research Journal)
Online ISSN : 1883-941X
Print ISSN : 0366-6190
ISSN-L : 0366-6190
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Volume 2013, Issue 116
Displaying 1-6 of 6 articles from this issue
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Original Articles
  • Characteristics of the Light Spectrum Environment of Honzu (orthodox shading) Covering Culture and Influence of UV Irradiation or Shielding on the Quality of Tea New Shoots
    Yasuko Kimura, Maho Kanda
    2013 Volume 2013 Issue 116 Pages 116_1-116_13
    Published: December 31, 2013
    Released on J-STAGE: December 31, 2015
    DOIhttps://doi.org/10.5979/cha.2013.116_1
    JOURNAL FREE ACCESS
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    The light spectrum environment of covering cluture was investigated.
    The spectrum of light transmitted by black synthetic fiber was found to be similar to light from the sun. However, it was observed that UV rays hardly penetrated honzu (orthodox shading), which is thatched with low UV-permeable materials;yoshizu (screens made of reeds); and rice straw.
    The influence of UV irradiation and shielding on the quality of new tea shoots was then investigated.
    It was found that UV shielding caused new tea leaves to be thinner, while the content of free amino acids, methyl methionine sulfonium chloride(MMSC), and caffeine all increased.
    Therefore, the quality of “covering culture” tea depends on the amount of UV irradiation, such that low UV-permeable covering like traditional honzu it contributes to higher quality tea.
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  • Key Odorants in the Headspace above Infused Sencha and in the Infusion
    Yuzo Mizukami
    2013 Volume 2013 Issue 116 Pages 116_15-116_21
    Published: December 31, 2013
    Released on J-STAGE: December 31, 2015
    DOIhttps://doi.org/10.5979/cha.2013.116_15
    JOURNAL FREE ACCESS
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    An aroma extract of the headspace above infused sencha (1.8 kg) was prepared by using a purge-and-trap technique. In addition, the extract of infusion (100 L) was obtained by distillation under a reduced pressure before solvent extraction followed by application of a strong vacuum using the solvent-assisted flavor evaporation technique. Odorants in the volatile fractions from the aroma extracts were identified using mass spectrometry, or single ion mode detection, as well as odor quality and retention indices by means of two types of fused silica capillary columns DB-wax and DB-5MS. An aroma extract dilution analysis has revealed that (Z)-1,5-octadien-3-one (metallic-like), (E,Z)-2,6-nonadienal (green) and 3-methynonane-2,4-dione (green) were the most prevalent odorants in the headspace above infused sencha; while 2 odorants, namely, β-damascenone (sweet) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (sweet) were potent odorants present in the infusion.
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