Location: Grain Quality and Structure ResearchTitle: Isolation and characterization of camelina protein fractions from camelina meal Author
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2014
Publication Date: 2/1/2014
Citation: Li, N., Qi, G., Sun, X.S., Wang, D., Bean, S. and Blackwell, D.L. 2014. Isolation and characterization of protein fractions isolated from camelina meal. Transactions of the ASABE. 57(1):169-178. Interpretive Summary: There is increasing interest in the use of proteins for bio-based products such as bio-plastics and adhesives. Protein rich co-products of fermentation and oil extraction procedures provide good starting material for the extraction of proteins for bio-industrial uses. This research project evaluated extraction procedures for extracting proteins from camelina meal, the residue left after extraction of oil from Camelina sativa. The physicochemical properties of the extracted proteins were also determined. Highest purity protein isolates were obtained when samples were first degummed. The major protein classes found in the camelina meal with globulin and glutelin, which as expected, differed in their physicochemical properties. Understanding how extraction procedures influence protein composition and functionality is important for the eventual use of any protein source, thus this research will aid in the continued development of proteins in bio-industrial applications.
Technical Abstract: Camelina protein fractions — albumin, globulin, and glutelins — were isolated from camelina meal using three different methods: the traditional Osborne sequence (S2), a modified Osbron sequence plus a degumming step (S1), and the isolation method without a degumming step (S0). The isoelectric points (pI) of albumin, globulin, and glutelin were found at pH 3.0, 3.0, and 4.5-5.0, respectively. S0 extracted the highest amounts of protein isolates but with the lowest protein purities due to the gum. S1 was more effective than S0 and S2 in terms of protein recovery and purities. Glutelin was the major camelina protein fraction (64.64%), followed by globulin (17.67%) and albumin (10.54%). The essential amino acids accounted for about 40% of the total amino acids, and essential amino acid profiles met or exceeded the WHO standards for children over 1 year old and adults. Camelina proteins had 26-28% hydrophobic amino acids, which is lower than canola, soy, and sorghum proteins. High molecular weight aggregates stabilized by covalent bonds in glutelin and albumin fractions as shown in SEC are closely related to their larger size protein aggregates observed in TEM images. Glutelins exhibited higher alpha-helix and beta-sheet ratios (1.03-1.05) than globulin fractions (0.91-1.00) and albumin (0.84).