A new cultivar of green tea ‘Danshin37’ was developed at the Tea Branch Facility, Miyazaki Agricultural Research Institute and released in 2018. ‘Danshin37’ was selected from seedlings of the crosses between ‘Saemidori’ and ‘Yumekaori’, which were carried out in 2000.

The characteristics of ‘Danshin37’ are as follows :

‘Danshin37’ is medium cultiver, which opens budding two day earlier than ‘Yabukita’ and plucks the first crop two days later than ‘Yabukita’. The shape of the plant is semi-erect, and its vigor is rather weak. The yield of first and second tea is higher than that of ‘Yabukita’.

‘Danshin37’ has high disease resistance to anthracnose （Discula theae-sinensis （I.Miyake） Moriwaki & Toy.Sato）， a slightly higher resistance to tea gray blight （Pestalotiopsis longiseta （Spegazzini） K.Dai & Tak. Kobayashi）， however, it is slightly susceptible to blister blight （Exobasidium vexans Massee）， and susceptible to bacterial shoot blight （Pseudomonas syringae pv.theae （Hori 1915） Young, Dye & Wilkie 1978）．‘Danshin37’ has very high insect resistance to mulberry scale （Pseudaulacaspis pentagona Targioni-Tozetti）．

‘Danshin37’ has high resistance to cold injury damage in winter.

The first tea is superior to ‘Yabukita’ and as good as ‘Saemidori’. In particular, the color, water color, and savoriness are excellent. The color, water color, and savoriness are especially excellent. ‘Kamairicha’ is also superior to ‘Yabukita’.

It has high suitability for short- to long-term covered cultivation, and can produce higher quality ‘Kabusecha’ and ‘Gyokuro’ than ‘Yabukita’.

It has higher suitability than ‘Yabukita’ and ‘Okumidori’ for ‘Mogacha’, which is used as powdered tea for processing.

Organic agriculture depends on natural enemies to prevent damage caused by insect pests. However, how the dynamics of insect pests and their natural enemies change with the transition to organic agriculture remains unclear. Here, we report seasonal variation in the emergence of Scirtothrips dorsalis Hood, Empoasca onukii Matsuda, and Aleurocanthus camelliae Kanmiya and Kasai （all sucking insects） and their natural enemies in three organic tea plantations. S. dorsalis and A. camelliae decreased from the third year of practice. Megaphragma sp., a natural enemy of S. dorsalis, and Encarsia smithi （Silvestri）, a natural enemy of A. camelliae （both Hymenoptera）, increased. These results suggest that the inhibitory effects of natural enemies on these two species are strong. On the other hand, inhibitory effects of natural enemies of E. onukii were not observed. This study provides information on how the number of sucking insect pests and natural enemies changes with the transition to organic agriculture, furthering our understanding of natural pest control.

The quality characteristics of matcha are created by fine grinding tencha. Therefore, the tools, implementation method, and indicators of sensory evaluation suited for the properties of matcha are described here.

The general tools used for sensory evaluation of tea include a matcha bowl for sensory evaluation and a tea whisk.

Sensory evaluation involves the examination of the following five items: color, particle size, foaming, foam color, and taste. Of these, color and particle size are evaluated by appearance, whereas foaming, foam color, and taste are evaluated after measuring 2 g of sample tea, pouring 100 mL of hot water into a matcha bowl for sensory evaluation, stirring with a tea whisk, and foaming.

The key point in the evaluation of each item is that the color should be bright （i.e., color tone that makes the vivid green stand out）. In terms of particle size, the particles should be finely aligned. For foaming, the tea should exhibit excellent foaming properties, fine foam, and stability. For foam color, the foam should be bright in a similar manner to appearance. In terms of taste, the tea should have a smooth mouthfeel, and the umami and shaded taste and the aromatic taste generated during the grinding process must be in harmony.

There is a certain degree of correlation between the sensory evaluation results and scientific measurements （i.e., colorimetric value and median diameter）.

Tea leaves （Camellia sinensis L.） during winter dormancy have been used to manufacture tea in some areas of Japan. Since little information is available on the ingredient contents of tea leaves during winter dormancy, we investigated the contents of caffeine, catechins, and flavonol glycosides of tea leaves harvested in October before wintering and February during dormancy. As results, the contents of caffeine, EGCG, and EGC in February decreased by approximately 50, 60, and 20%, respectively, compared with October. Most of the 16 investigated flavonol glycosides did not change, but the contents of Q-GRhG, Q-GRh, Q-Ga, Q-G, and K-GRh were increased in February compared with October.

Tea contains more than 600 types of aroma components with significantly different physicochemical properties, such as molecular weight, boiling point, and polarity. The recovery rates of these aroma components differ depending on the isolation method used. Various techniques for the isolation of aroma components have been investigated to date. This paper reviews previously reported methods for isolating aroma components from tea.

Moreover, this paper discusses solvent refining, identification of aroma components, and the analytical conditions for gas chromatography. The isolation methods discussed include atmospheric distillation, simultaneous distillation using the Likens–Nickerson apparatus, vacuum distillation, high-vacuum distillation using a solvent-assisted flavor evaporation unit, reflux, liquid–liquid extraction, solvent elution following column adsorption, cold trap, purge and trap, solid-phase microextraction, and stir bar sorptive extraction.