Oxidation; fermentation (A23F3/08)

Stevia leaves tea production method

Invention relates to food industry. Twisted tender stevia leaves are air-dried, twisted and separated from coarse leaves and stems. The coarse leaves and stems are delivered for a second twisting process stage and a subsequent stage of fermentation during 45-50 minutes at parameters similar to the parameters of fermentation twisted tender leaves undergo. The raw material is milled, granulated and dried. Fermentation is performed in an electric field with nanosecond pulse electric field with output pulse voltage amplitude equal to 5.0-6.0 kV, pulse duration being 5-10 ns, pulse-repetition frequency being 450-500 MHz, treatment time lasting 1.0-1.5 minutes with subsequent rest period lasting 3.0-3.5 minutes, with alternating during 30-35 minutes.

Tea production

Method of water-soluble black leaf tea includes stages (a) of possible withering of collected tea leaves, (b) leaves maceration, (c) their fermentation, (d) leaves thermal treatment for discontinuance of fermentation and (e) further drying with preparation of black leaf tea. Method suggests that tea leaves are treated prior to fermentation or intermediate fermentation with substance that reduces pH, with further treatment in the process of fermentation with ascorbic acid, salts of ascorbic acid or their mixtures at the stage of intermediate fermentation or later, which are taken in amount that is sufficient for preparation of black leaf tea, which is infused in water at temperature of 5-100°C.

Method for producing black tea

The present innovation deals with drying the first supply of freshly collected tea leaves, maceration of dried leaves, keeping macerated, dried leaves for fermentation to obtain macerated tea mass. Then comes drying the second supply of freshly collected tea leaves followed by mixing macerated tea mass obtained out of the first supply of tea leaves with dried leaves obtained out of the second supply of tea leaves followed by rolling the mixture and keeping the rolled mixture for fermentation and drying fermented mixture to obtain black leaf tea. This enables to obtain black leaf tea which by touch and in appearance is similar to tea produced by orthodoxal technique but has characteristics of the tincture of more completely fermented tea.