Patent ID: 7677253

Claim:
A method of manufacturing a regenerated tobacco material, comprising: (a) extracting a natural tobacco material with an extracting solvent to obtain an extracted solution containing components of the natural tobacco material and an extraction residue, the natural tobacco materials containing both desired and undesired components, wherein the desired component is nicotine, and the undesired component is selected from nitrates and/or tobacco-specific nitrosamines (TSNAs); (b) fractionating the extracted solution to obtain a first fraction enriched in the desired component and depleted in the undesired component and a second fraction enriched in the undesired component and depleted in the desired component; (c) preparing a regenerated tobacco web from the extraction residue; and (d) adding the first fraction to the regenerated tobacco web optionally together with the second fraction decreased in amount, wherein the fractionating treatment is carried out by means of a reverse osmosis filtration membrane to obtain a membrane permeate fraction and a membrane non-permeate fraction; and wherein the fractionating treatment is carried out a plurality of times by means of membranes differing from each other in cut-off molecular weight, and one or more of membrane non-permeate fractions and membrane permeate fractions obtained from the fractionating treatment are added to the regenerated tobacco web, provided that, where all of the obtained membrane non-permeate fractions and the membrane permeate fractions are added to the regenerated tobacco web, the amount of at least one of the obtained membrane non-permeate fraction and the membrane permeate fraction is decreased in adding the fractions to the regenerated tobacco web.