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: This invention relates to a method for enhancing the smoke flavor of a smoking material by treating the said material with an agent comprising 3-hydroxysclareol, particularly with the compound 3.beta.-hydroxysclareol. The invention further relates to the smoke-enhancing agent and a method by which it can be obtained by subjecting sclareol to a microbial transformation process. Finally it extends to smoking material incorporating the said agent.

Abstract: The invention is concerned with a process for improving the smoking properties of a tobacco smoking material in which the tobacco material is subjected to treatment with at least one amylolytic enzyme capable of converting the starch contained in the tobacco into sugar. The amylolytic enzyme or a source thereof may be added to the tobacco material, for example to an aqueous dispersion of the latter.