Sencha, Ryokucha tea: hidden uses and properties
Ryokucha, also known as Sencha, is a variety of Japanese green tea. It is the most popular type of green tea in Japan, accounting for about 80% of the green tea produced in the country.
Sencha is produced without the use of steam to stop the oxidation of the leaves, unlike other types of Japanese green tea like matcha. After harvesting, the leaves are rolled, shaped, and then dried. This process gives Sencha its characteristic fresh and slightly bitter flavor.
Industrial Production Process
- Leaf Harvesting. The production of Sencha begins with the harvesting of young tea leaves from the Camellia sinensis plant. Harvesting takes place in spring when the leaves are at their peak of freshness and quality.
- Steaming. Immediately after harvesting, the leaves are exposed to steam for a short period. This process, known as steaming, serves to deactivate the enzymes responsible for oxidation, thus preserving the green color and antioxidant properties of the leaves.
- Cooling and Drying. After steaming, the leaves are quickly cooled and then dried. This step is crucial to stop any fermentation process and to start the drying process.
- Rolling. The dried leaves are then rolled to break the cell walls, facilitating the release of juices and essential oils during infusion. Rolling gives the leaves their characteristic shape.
- Final Drying. The leaves are further dried to reduce the moisture content to the desired level. This final step ensures the tea's preservation and defines its flavor.
- Selection and Grading. After drying, the Sencha is selected and graded based on quality, flavor, and appearance. Only leaves that meet strict standards are packaged as Sencha.
Habitat and Cultivation
Sencha is grown in various regions of Japan, with Shizuoka, Kagoshima, and Uji in Kyoto being among the most renowned for producing high-quality tea. The quality of Sencha can vary significantly depending on the terroir, cultivation method, and harvest season.
Nutritional Properties and Benefits
Sencha is rich in antioxidants (1), particularly catechins, which have been shown to have numerous health benefits, including reducing the risk of heart disease and certain types of cancer (2). It also contains L-theanine, an amino acid that can help promote relaxation and mental well-being.
Uses
Traditional Consumption: Sencha is traditionally enjoyed on its own, without the addition of milk or sugar, to fully appreciate its flavor.
Tea Ceremony: Although less formal than matcha used in the Chanoyu tea ceremony, Sencha is sometimes used in less formal occasions.
Culinary: Sencha can also be used in cooking, for example in recipes for sweets or as an ingredient in savory dishes.
Environmental Impact
The cultivation of Sencha, as with other teas, can have an environmental impact depending on the agricultural practices used. Organic and sustainable cultivation of Sencha is becoming increasingly popular as a way to reduce this impact.
Conservation
Proper storage of Sencha is crucial to maintaining its flavor and beneficial properties (3). It should be stored in a cool, dry place, away from direct sunlight and strong odors.
References_____________________________________________________________________
(1) Masek, A., Chrzescijanska, E., Kosmalska, A., & Zaborski, M. (2012). Antioxidant activity determination in Sencha and Gun Powder green tea extracts with the application of voltammetry and UV-VIS spectrophotometry. Comptes Rendus. Chimie, 15(5), 424-427.
Abstract. This article presents the electrochemical analysis of the oxidation of rutin and green tea extract solutions and the antioxidative properties of these substances. Flavonoids and other polyphenols contained in green tea have antioxidative properties due to the presence of various numbers of hydroxyl groups in different arrangements. The investigation of the oxidation of green tea extracts was performed to identify the most effective antioxidant. The cyclic and pulse voltammograms show that the extract of Gun Powder (GP) green tea contained rutin and other polyphenols, while the extract of Sencha (S) tea contained other antioxidants that are oxidised at a more positive potential. The GP extract showed slightly better antioxidative properties than did the S extract. The UV-VIS spectra show that, in addition to flavonoids extracts contain chlorophyll. The results obtained demonstrate that the tested tea extracts show very good antioxidative properties and therefore may be considered as potential stabilising agents that are able to reduce the rate of undesirable oxidation processes.
(2) Lu X, Saeed MEM, Hegazy MF, Kampf CJ, Efferth T. Chemopreventive Property of Sencha Tea Extracts towards Sensitive and Multidrug-Resistant Leukemia and Multiple Myeloma Cells. Biomolecules. 2020 Jul 4;10(7):1000. doi: 10.3390/biom10071000. PMID: 32635587; PMCID: PMC7407630.
Abstract. The popular beverage green tea possesses chemopreventive activity against various types of tumors. However, the effects of its chemopreventive effect on hematological malignancies have not been defined. In the present study, we evaluated antitumor efficacies of a specific green tea, sencha tea, on sensitive and multidrug-resistant leukemia and a panel of nine multiple myelomas (MM) cell lines. We found that sencha extracts induced cytotoxicity in leukemic cells and MM cells to different extents, yet its effect on normal cells was limited. Furthermore, sencha extracts caused G2/M and G0/G1 phase arrest during cell cycle progression in CCRF/CEM and KMS-12-BM cells, respectively. Specifically, sencha-MeOH/H2O extracts induced apoptosis, ROS, and MMP collapse on both CCRF/CEM and KMS-12-BM cells. The analysis with microarray and COMPARE in 53 cell lines of the NCI panel revealed diverse functional groups, including cell morphology, cellular growth and proliferation, cell cycle, cell death, and survival, which were closely associated with anti-tumor effects of sencha tea. It is important to note that PI3K/Akt and NF-κB pathways were the top two dominant networks by ingenuity pathway analysis. We demonstrate here the multifactorial modes of action of sencha tea leading to chemopreventive effects of sencha tea against cancer.
(3) Qin, W., Yamada, R., Araki, T., & Ogawa, Y. (2022). Changes in morphological and functional characteristics of tea leaves during Japanese green tea (Sencha) manufacturing process. Food and Bioprocess Technology, 1-10.
Abstract. Japanese green tea (Sencha) is mainly manufactured by six processing steps: steaming, primary rolling, rolling, secondary rolling, final rolling, and final drying. The morphology and microstructure of tea leaves were observed, and total polyphenol content (TPC) and total antioxidant activity indexed by FRAP and DPPH were evaluated in tea leaves and infusions during processing. Folds or wrinkle-like microstructures on the tea leaf surface increased during processing, particularly during the primary rolling (PR) step. Leaf shape also mainly collapsed during the PR step. In tea leaves, the values of TPC, DPPH, and FRAP during processing ranged from 189 to 283 mg GAE/g dry matter (DM), 2670–4363 μmol FeSO4/g DM, and 1519–2327 μmol TE/g DM, respectively, whereas in the hot water extraction as a tea infusion decreased and ranged from 14 to 135 mg GAE/g, 391–2961 μmol FeSO4/g DM, and 219–1049 μmol TE/g DM, respectively. These functional attributes increased mainly from steaming (ST) to rolling (RL) steps. The results indicated that the processing conditions at each step, especially at the steps for ST, PR, and RL, influenced the apparent quality of the final tea leaf products and the functional properties of tea leaves and infusions.
Ryokucha 
