Deproteinization Effects on Homogenized Leaf Cured (HLC) Products

The HLC deproteinized product [depro] with 34 % of its original dry weight removed as heat precipitable protein fractions, shows a reduction in the levels of most of the cured product constituents and the major pyrolyzate constituents while the levels of polycyclic aromatic hydrocarbons and volatile nitrosamines in the pyrolyzates from the HLC deproteinized product were increased. This indicates that the precursors of the polycyclic aromatic hydrocarbons in the pyrolyzate from the HLC deproteinized product were not removed with the protein precipitates. Another possibility is that some constituents in the protein precipitates that were removed from the HLC deproteinized product may have had an inhibitory effect toward the formation of the polycyclic aromatic hydrocarbons in the pyrolyzates of the HLC control and flue-cured reference during their pyrolysis, since the protein precipitates were not removed from these products. Generally, the levels of polycyclic aromatic hydrocarbons from the pyrolyzates of the HLC products were higher than those from the pyrolyzates of the flue-cured reference. This could be a result of the tobacco maturity or curing methods. The level of the volatile nitrosamines in the pyrolyzates of the HLC control was lower than those levels in the pyrolyzates of the HLC deproteinized and flue-cured reference products. This could be due to pyrolytic interaction between some constituents in the sample and the protein precipitate which was not removed from the HLC control product. Additional work is needed to clarify these differences. A reduction in the level of solanesol was evident in the HLC deproteinized product probably due to the association of solanesol with the chloroplastic protein precipitate that was removed from that product. In addition, the level of solanesol was highest in the flue-cured reference, which is in agreement with previous reports that solanesol concentration increases with tobacco maturity. This report demonstrates that HLC can be used to manipulate the chemical composition of tobacco. The levels of some major constituents were decreased while the levels of polycyclic aromatic hydrocarbons were increased in the pyrolyzate from the same tobacco product.