Changes in Gustatory Substances and Palatability of Matcha (powdered Tencha) during Aging of Tencha (green tea)

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Changes in gustatory substances and palatability of Matcha (powdered Tencha) during aging of Tencha (green tea) in the atmosphere of air or nitrogen at 10℃ were investigated. The Matcha prepared in the Tencha aged for 6 months in the atmosphere of air was feted sweet taste and umami more strongly, astringent and bitter taste more weakly, and flavor more palatably by analytical panels, compared with the Matcha prepared in fresh (unaged) Tencha or Tencha aged under atmosphere of nitrogen for 6 months. The contents of catechins in the eluate of Matcha decreased slightly during aging under both air and nitrogen atmospheres. The contents of caffeine, free amino acids (containing theanine) and saponin in the eluate of Matcha remained constant values during aging for 6 months. The free sugar contents decreased slightly for aging under atmosphere of air. The foaming volume of Matcha increased by aging of Tencha and became greater on the aging under air than under nitrogen. The viscosity of eluate of Matcha and the content of pectin increased during 6 months of aging both atmosphere conditions. The improvement of palatability for Matcha by aging of Tencha may be attributable to the increase of foaming volume.The residual rates of the apparent total vitamin C and ascorbic acid in Tencha were about 80% in air and 90% in nitorgen after 6 months of storage, respectively. The contents of chlorophyll and its related derivatives in Tencha varied very little both atmospheric conditions after 6 months of storage. Though chlorophyllase remained enough activity to react after 6 months-storage of Tencha, the enzyme did not cause the degradation of chlorophyll in Tencha under the storage condition of low moisture. These results indicate that Tencha have maintained satisfactory quality during the 6 months-storage in air at 5℃ for aging to favorable Matcha.Catechins, caffeine and pectin did not contribute to the difference in palatability of Matcha with picking time of tea leaves.