Abstract: A tobacco-treatment process comprises mechanically expressing cell-sap from yellowed, substantially undried, tobacco-leaf material, impregnating the fibrous material remaining after the expression with said cell-sap or with parts or components of said cell-sap or with cell-sap expressed from other yellowed, substantially undried, tobacco leaf material, and drying the sap-impregnated material. The tobacco leaf material may comprise leaves harvested in a fully developed and mature state. The leaves may be at least partly yellow when harvested. They may have been yellowed by the application of a yellowing agent to tobacco plants or yellowing may have been effected or completed by heaping or rack-hanging the harvested leaves in an enclosed atmosphere, suitably with a relative humidity of 70% or more and a temperature in the range of 20.degree. to 40.degree. C. Ethylene gas may be introduced into the atmosphere to promote the yellowing.

Abstract: Harvested green tobacco is cured by photobleaching followed by thermal browning. Photobleaching is preferably effected after incubation in vapors of an organic liquid or steam.

Abstract: A process for artificially curing mature green tobacco is provided wherein the tobacco is immersed in an acidic medium and incubated therein at at least room temperature until the desired color develops. Incubation at pH 1.5 to 3.5 at about 50.degree. C. for as little as 3 hours may be sufficient to eliminate the green color and green smoke taste and odor of the tobacco.

Abstract: A method is provided for treating uncured green tobacco whereby the chemical composition of the tobacco can be altered. The method involves expressing protoplasmic juice from green uncured tobacco by means of pressure and thereafter artificially curing the tobacco. The expressed juice may be collected and processed to alter its chemical composition. The processed juice may thereupon be reapplied to tobacco from which juice has been expressed to produce a tobacco product having desired chemical characteristics.