• The Korean Journal of Food And Nutrition
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• v.27 no.2
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• pp.156-163
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• 2014

In order to develop tea by using the leaves of stevia, which is a herbal plant, and to solve the disadvantages of stevia dried leaf tea, we have manufactured the steamed tea, stir-fried tea and fermented tea by changing the manufacturing processes. As a result of the sensory tests, the steamed tea, stir-fried tea and fermented tea received higher evaluations than the dried leaf tea. In terms of efficiency, it is desired that the total number of steaming and stir-frying is only once, but the fermentation is found to be the most desirable for 2 days. There are no trends for changes in the general ingredients, mineral and free amino acid contents of stevia leaf teas by different manufacturing processes. As a result for the measurement of antioxidant activities, the steamed tea and dried leaf tea did not show significant differences, but the stir-fried tea and the fermented tea show significantly low antioxidant activities as compared to the steamed tea. The contents of stevioside in both the stir-fried tea and the fermented tea were less than that in the dried leaf tea, but in the steamed tea, there was no significant difference in the content of stevioside. Base on the present observations, this study supports high potentials of steaming process in order to produce new stevia leaf tea.

• Korean Journal of Pharmacognosy
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• v.9 no.3
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• pp.149-156
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• 1978

The result of the study about the cultivation, the constituents, the sweetenity, and the development of preparations of Stevia and Hydrangea are as follows: 1. Hydrangea thrived at $200{\sim}1,400m$ above the sea-level, and the good ones were brought up at $600{\sim}1,200m$. 2. The good ones which belonged to the genera of Hydrangea were produced in the damp, dark and cold place. 3. The growth and cultivated yield of Stevia was not significantly influenced by the acidity of the soil. 4. The best season was May and June for propagation of Stevia by cutting method. 5. The growth rate of Stevia and Hydrangea was really good in the sandy fertile soil, but in the mucotic soil it was not suitable. 6. The extraction and separation of phyllodulcin by solvent had many difficulties, because it was very soluble in water, ethanol, ether, petroleum ether, acetone and benzene, etc. 7. The solubility of stevioside on the solvent was as follows: It was very soluble in water and methanol, slightly soluble in ethanol and acetone, and insoluble in ether, petroleum ether and chloroform. 8. The alkaloid reaction by Mayer reagent in Hydrangea extract was positive. 9. The ashification rate of Stevia was 8.66% to 8.72% and that of Hydrangea 17.02% to 17.04%. 10. The tannin of Stevia leaf was 7.80% to 7.88% and its of Hydrangea decreased 9.46% to 6.08% by fermentation. 11. The percent rates in minimum concentration-occurring sweetness in sugar, glycyrrhiza methanol extract, Hydrangea water extract, Stevia leaf water extract, decoction of Stevia's leaf, decoction of Stevia's stem were as follows: 1.2, 0.1, 0.1, 0.2, 0.4, 0.01, 0.1, 0.6. and sweetenity ratios of those were 1, 12, 12, 6, 3, 64, 12, 2, 12. It was very meaningful to develop preparations of stevia as stevioside, micronized powder, water extract, methanol extract and compound teas and in Hydrangea, water extract, methanol extract, single tea, and compound teas were less meaningful. 13. The genera of Hydrangea which is natural species in Korea was positive in phyllodulcin-identification test, but it was not available to make the sweet tea because of having a little content.