An improved method for extraction of sorghum polymeric protein complexes. (January 2020)

• Record Type: Journal Article
• Authors: Ioerger, B.P.; Bean, S.R.; Tilley, M.; Lin, H.
• Is Part Of: Journal of cereal science. Volume 91(2020)
• Publication Date: 2020-01
• Subjects: Sorghum -- Protein -- Protein complexes -- Protein extraction -- Size exclusion chromatography -- Cereal -- Grain; PMSF Phenylmethylsulfonylfluoride -- PIC Protease inhibitor cocktail -- SEC Size-exclusion chromatography -- F1 Fraction 1 -- F2 Fraction 2 -- F3 Fraction 3 -- SDS Sodium dodecyl sulfate -- RP-HPLC Reversed phase – high performance liquid chromatography -- SDS-PAGE Sodium dodecyl sulfate polyacrylamide gel electrophoresis; Grain -- Periodicals; Cereal products -- Periodicals; Céréales -- Périodiques; Produits céréaliers -- Périodiques; Cereal products; Grain; Periodicals; 664.705
• DOI: 10.1016/j.jcs.2019.102876
• Languages: English
• ISSNs: 0733-5210

Abstract

Abstract: A method for fractionating sorghum proteins using extraction solvents and techniques designed to obtain polymeric protein structures (especially disulfide linked) was developed. Extraction and separation conditions were optimized in terms of completeness of protein extraction, sample stability, and analytical resolution. After pre-extraction of albumins and globulins, a 3-step sequential procedure involving no reducing agents was applied to ground whole sorghum flour. The three fractions obtained represented proportionally different protein polymer contents and molecular weight distribution as evidenced by comparative size exclusion chromatography. Protein composition also varied among the extracts with differences in kafirin composition and non-kafirin proteins detected in the fractions by RP-HPLC and SDS-PAGE analysis. The ability to quantify and further characterize sorghum polymeric protein complexes will be useful for additional studies linking protein structures with functionality and digestibility and variations for these properties within diverse sorghum germplasm. Graphical abstract: Image 1 Highlights: Heat treatment of extracts was the most effective in stabilizing polymeric proteins. Approximately 90% of sorghum proteins were extracted without a reducing agent. Extracted fractions varied in monomeric/polymeric protein content and composition.