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Extraction, identification and characterization of the water‐insoluble proteins from tobacco biomass
Author(s) -
Teng Zi,
Wang Qin
Publication year - 2012
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.4708
Subject(s) - chemistry , chromatography , methionine , aqueous solution , extraction (chemistry) , amino acid , protein purification , residue (chemistry) , polysaccharide , biochemistry , organic chemistry
BACKGROUND: Tobacco leaves are a potential candidate for plant proteins, yielding fourfold more protein per acre than soybeans. However, more than 60% of these proteins are water‐insoluble and remain in the residue (referred to as ‘tobacco biomass’) after aqueous extraction. Efficient extraction of tobacco biomass proteins (TBPs) could boost the development of value‐added products from tobaccos. RESULTS: TBPs were resistant to salt extraction at pH 2.0–12.0, but they were readily extracted by organic solvents. A simplified extracting method, including mechanical homogenization, a first extraction with a methanol–water mixture (40/60, v/v) and a second one with water at pH 6.0, recovered at most 68% of the TBPs. Analysis by sodium dodecyl sulfate–polyacrylamide gel electrophoresis indicated the presence of both the water‐soluble tobacco F 1 protein and the less soluble cell wall proteins in TBPs, while Fourier transform infrared spectra suggested the coexistence of TBPs with polysaccharides (especially pectin). Meanwhile, a higher content of hydrophobic amino acids was found in TBPs compared with water‐extractable tobacco proteins. The amino acid score of TBPs was 0.71, with cysteine and methionine being the primary limiting amino acids. CONCLUSION: Satisfying recovery of TBPs was achieved using a two‐step organic solvent extraction. The hydrophobicity and protein–pectin interaction of TBPs explained for this result. Copyright © 2011 Society of Chemical Industry