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Volume 2012 (2012)
- Issue 114 Pages 114_1･･･
- Issue 113 Pages 113_1･･･
Volume 2012, Issue 113
Displaying 1-9 of 9 articles from this issue
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Review
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Manami Monobe2012 Volume 2012 Issue 113 Pages 113_1-113_9
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESS
Original Articles
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Toshihiro Tanaka, Yoshie Miza, Tsuyoshi Tomihama, Daisuku Horiguchi, S ...2012 Volume 2012 Issue 113 Pages 113_11-113_26
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSIn the initial stage of frost protection by using sprinklers for water application, the surface temperature of the tea canopy usually drops to the critical temperature of -2 °C, which causes freezing damage in new shoots of tea, and then suddenly rises to the freezing point of water 0 °C. Thus far, this first decline in temperature has been attributed to insufficiency of water for application. However, we conducted this study by considering the possibility that this decline was associated with supercooling. The conclusions were as follows.
1. Distilled water that contained new shoots of tea supercooled in incubator as same as suspension of ice nucleation active bacteria.
2. New shoots of the first tea crop in supercooled water were not damaged even at -3 °C, but were damaged when the temperature of the tea leaves dropped below -1.1 °C after freezing of water.
3. We developed a new water-application system in which irrigation starts if the surface temperature of the tea canopy drops below -0.4 °C and stops if the surface temperature rises above -0.3 °C for 3 min; we also conducted field frost-protection experiments.
4. The use of the new system in the spring of the year 2011, which had frequent hard frost, prevented frost-induced damage in tea shoots. In addition, with the use of the system, there were few instances of water application when the tea leaf temperature did not decline below -0.4 °C. Furthermore, the water consumption by the system in the spring of 2011 was 23% less than that of a 100-s rotation application system popular in Soo in Kagoshima Prefecture.
Our data indicated that freezing-induced damage of tea shoots did not occur in the supercooling water if the temperature of the tea leaves dropped below the freezing point of water. Our water application system, which helped maintain the tea canopy temperature above its critical temperature, proved highly effective with regard to frost protection and water consumption.View full abstractDownload PDF (969K) -
Shingo Toyoshima, Chikara Ishijima, Yasushi Sato2012 Volume 2012 Issue 113 Pages 113_27-113_34
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSSpecies diversity and seasonal dynamics of carabid beetles attracted to a light trap (LT) sited in a tea plantation were compared with those estimated using pitfall traps (PFT) to evaluate efficacy of the LT examination. A total of 1,959 beetles (52 species of 24 genera) were caught in LT from May 25 to October 25, 2010. Species composition of the abundant species caught in LT was more diverse than that estimated using PFT, though Synuchus arcuaticollis, a major species caught in PFT, was not caught in LT. The indices of species diversity were calculated as 0.794 (Simpson’s D) and 2.198 (Shannon-Wiener’s H’), which were higher than those estimated using PFT. Thus, LT has an ability to collect more diverse carabid beetles, but should be supplemented by PFT data for more accurate evaluation of the species diversity of carabid beetles.View full abstractDownload PDF (760K) -
Hirofumi Matsuo, Susumu Fujita, Toshihiro Tatsuno, Yoshinori Nagase, M ...2012 Volume 2012 Issue 113 Pages 113_35-113_54
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSThe heat flow and thermal efficiency of a secondary tea dryer for kamairi-cha were examined in the case of using in a secondary tea drying and a final tea drying. The required heat for green tea leaves was calculated to be about 2,300(kJ/kg) for the secondary tea drying, about 960(kJ/kg) for the final tea drying, of which 19.4(%) for the secondary tea drying , 22.3(%) for the final tea drying was used as the heat of evaporation. The thermal efficiency of the secondary tea dryer for kamairi-cha did not change under the range of experimental condition used. Thermal efficiency of a secondary tea dryer for kamairi-cha was 19.5(%) for the secondary tea drying, 22.2(%) for the final tea drying.View full abstractDownload PDF (2686K) -
Yuzo Mizukami2012 Volume 2012 Issue 113 Pages 113_55-113_62
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSAn aroma extract of the roasted green tea was prepared by using the solvent-assisted flavor evaporation technique (10-3 Pa). An aroma extract dilution analysis applied to the volatile fraction revealed 50 odor-active peaks with the flavor dilution factors (FDf) between 10 and 10000. Among these odorants, furfuryl mercaptane and 2-vinyl-3,5-dimethylpyrazine were identified for the first time among the tea volatiles. Two odorants of 2-ethyl-3,5-dimethylpyrazine and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were the most important components of the characteristic aroma in the roasted green tea with the high FDfs of 10000. As well as these, 2-acetyl-1-pyrroline, (Z)-1,5-octadien-3-one, furfuryl mercaptane, 2,3-diethyl-5-mehylpyrazine, (E,E)-2,4-nonadienal, β-damascone and β-damascenone were also key odorants with the FDfs of 1000.View full abstractDownload PDF (827K)
Short Communication
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Katsuyuki Yoshida, Kiyoshi Matsuo2012 Volume 2012 Issue 113 Pages 113_63-113_69
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSWe developed a simple method of estimating the freezing resistance of tea plants by measuring electrolyte leakage from low-temperature-treated overwintering buds and leaves. Overwintering buds and leaves were treated with subfreezing temperatures (−2°C to −15°C) in a controlled freezer for 1 hr and incubated for one hour at 15°C in a growth chamber. Each overwintering bud and leaf was then immersed in distilled water adjusted to 20 times (bud) or 40 times (leaf) the volume of the plant tissue’s weight. Electric conductivity (EC) of the water in which tissue was immersed was measured by a conductivity meter at 0, 60 and 120 minutes after addition of water. Freezing damage to tissues was confirmed by 0.1% (w/v) Evans blue staining after EC measurement. The increase of EC of tissue immersed in water from 0 to 120 minutes indicated the degree of freezing damage to buds and leaves. The freezing resistance of buds and leaves could be estimated from the variation in increase of EC value among the tissues treated at different temperatures, to an accuracy of 1°C. This method is an easy, precise method of evaluating the freezing resistance of tea plants and would be useful for monitoring changes in the freezing resistance of tea plants from autumn to spring to avoid frost damage.View full abstractDownload PDF (788K) -
Manami Monobe, Kaori Ema, Yoshiko Tokuda, Mari Maeda-Yamamoto2012 Volume 2012 Issue 113 Pages 113_71-113_76
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSCatechins, one of the main components in green tea extract, have antioxidative activity and immunomodulating activities, and play an important role in reducing the risk of disease. The most abundant catechins in a green tea extract are epigallocatechin gallate (EGCG) and epigallocatechin (EGC), and the EGCG/EGC ratio in a green tea extract was affected by the extraction temperature. We found that the cold water extract or the catechin mixture with a high EGC ratio induced greater immunoglobulin A (IgA) production by murine Peyer's patch (PP) cells. Here, we investigated the effect of cold water extract of green tea on salivaly sIgA levels in habitual green tea (hot water extract) drinker.View full abstractDownload PDF (757K)
Technical Reports
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Hirofumi Matsuo, Susumu Fujita, Toshihiro Tatsuno, Yoshinori Nagase, M ...2012 Volume 2012 Issue 113 Pages 113_77-113_80
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSWe calculated the amount of heat needed for the tea manufacturing process of Kamairi-cha. The amount of heat needed to produce 1 kg of Kamairi-cha crude tea was approximately 32,000 kJ in the manufacturing process: parching → tea rolling → secondary tea drying → final tea drying → tea drying; approximately 25,000 kJ in the manufacturing process: parching → tea rolling → secondary rolling, drying → final tea drying → tea drying; and approximately 26,000 kJ in the manufacturing process: parching → primary drying → tea rolling → secondary rolling, drying → final tea drying → tea drying, while for the Sen-cha crude tea, approximately 28,000 kJ was required. To increase the thermal efficiency of tea manufacturing process of Kamairi-cha, replacing secondary tea dryer with secondary tea rolling dryer gave an improvement. But, this method potentially led to the loss of characteristic flavor of Kamairi-cha. Thus, improving thermal efficiency of secondary tea dryer is greatly needed.View full abstractDownload PDF (663K) -
Tomohiro Taniguchi, Yoshinori Gejima, Hirofumi Matsuo, Susumu Fujita, ...2012 Volume 2012 Issue 113 Pages 113_81-113_91
Published: June 30, 2012
Released on J-STAGE: October 30, 2015
JOURNAL FREE ACCESSThis study compared the contents of catechins and caffeine in Kamairi-cha, which had been produced by three different commonly-used manufacturing lines, with those in Sen-cha. Consequently, no differences were observed in the contents of catechins and caffeine in the crude tea between Kamairi-cha and Sen-cha. However, the contents of catechins and caffeine in the infusion from Kamairi-cha were lower than those from Sen-cha although the infusion was obtained under different conditions, including infusing temperature, infusing time and others. In particular, the lowest contents of catechins and caffeine were obtained in the infusion from Kamairi-cha when a secondary tea drying machine was used in the manufacturing line. The reason for this was considered to be due to a short duration of the pressing process, by which the cellular tissues of tea leaves were slightly damaged.View full abstractDownload PDF (1281K)
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