Abstract: The disclosure describes methods for the purification of protein-enriched extracts to provide concentrates and isolates and methods for incorporation of such materials into products. The purification methods are adapted for removal of one or more of ash, metal salts, alkaloids, particulates, heavy metals, and other impurities and/or contaminants from extracts, as well as modifying the sensory characteristics (e.g., odor, color, and/or taste characteristics) of extracts. The methods generally include diafiltration, treatment with functionalized resins, and supercritical extraction. A protein composition in the form of a concentrate or isolate is provided, the protein composition including RuBisCO, F2 fraction proteins, or combination thereof extracted from a plant of the Nicotiana species, wherein the protein composition is characterized by one or more of: an ash content of less than about 15% by weight; a nicotine content of less than about 10 ?g/g, and a heavy metal content of less than about 60 ?g/g.

Abstract: Methods of forming pyrazines from reactants derived from a plant of the Nicotiana species, including receiving an aqueous reactant solution including at least one tobacco-derived cellulosic sugar and at least one tobacco-derived amino acid, heating the reactant solution to a reactant temperature and holding the reactant solution at the reactant temperature for a reactant time to produce a reactant product including at least one tobacco-derived pyrazine, and isolating the at least one tobacco-derived pyrazine from the reactant product. Tobacco products incorporating the tobacco-derived pyrazines are also provided.

Abstract: Methods of forming pyrazines from reactants derived from a plant of the Nicotiana species, including receiving an aqueous reactant solution including at least one tobacco-derived cellulosic sugar and at least one tobacco-derived amino acid, heating the reactant solution to a reactant temperature and holding the reactant solution at the reactant temperature for a reactant time to produce a reactant product including at least one tobacco-derived pyrazine, and isolating the at least one tobacco-derived pyrazine from the reactant product. Tobacco products incorporating the tobacco-derived pyrazines are also provided.