Investigations into the chemistry of the flue-curing of tobacco

Abstract

IN connexion with an attempt to grow in Assam tobacco suitable for the manufacture of cigarettes, the opportunity was taken of starting investigations upon the chemical changes that occur in flue-curing. This appears to be the process best suited for the type of leaf grown.The curing was carried out in substantially the same way as recommended by Brown [1933]. The curing barn is filled with leaf, preferably of the same texture and ripeness, and the barn is then sealed. The door and all ventilators are closed, so that no moisture can escape. The furnace is lit and the temperature of the barn maintained at 85-900 F. At this temperature metabolic processes will be taking place almost at their maximum rate and the sealing of the barn ensures that the loss of moisture will be slight. The temperature is

Chemical Changes in the Harvested Tobacco Leaf: Part II. Chemical and Enzymic Conversions during Fermentation and Aging

“…In a special study, E. A. H. Roberta (180) investigated the respiratory activity of the leaves of a cigarette tobacco grown in India a t various succeseive stages of the flue-curing prooeas. As long aa the leaves had been exposed in the curing barn to temperatures not exceeding about 55°C.…”

“…The oxidation of the "polyphenols" is a significant effect not only per se, but also in view of the possibility that these compounds may act as oxygen-transferring agents, and as mediators for the oxidation of other leaf components which, without such mediation, would remain unchanged. Roberts (179)(180)(181)(182) expresses the opinion that the phenolic compounds may introduce, via a dynamic change between their hydroquinone and quinone forms, the direct oxidation of hydroxy acids and carbohydrates. Thus, the actions of the autoxidizable compounds are possibly of great importance for the entire fermentation process.…”

Different yellowing degrees and the industrial utilization of flue-cured tobacco leaves

“…In flue-cured tobacco production, the flue-curing process exerts an important influence on the yield and value of tobacco leaves and directly influences the appearance of flue-cured tobacco leaves and conversion of internal chemical constituents, such as polyphenols (Roberts, 1941;Gong et al, 2009). Specifically, the degree of yellowing plays an important role in the whole curing process because the peak period of the conversion of primary chemical components in fresh tobacco leaves occurs upon yellowing, which is extremely important when forming tobacco quality (Gong et al, 1996).…”

Effects of enzymatic browning reaction on the usability of tobacco leaves and identification of components of reaction products

“…In the 1940s, Roberts 4 proposed that an enzymatic browning reaction is responsible for appearance of grey speckles during flue-curing. During flue-curing, as the temperature rises to about 46 °C (temperature at which cell death occurs in most plants), the cytoplasmic membrane loses its selective permeability 5 .…”