Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2014
Publication Date: 7/25/2014
Citation: Hojilla-Evangelista, M.P., Selling, G.W., Berhow, M.A., Evangelista, R.L. 2014. Preparation, composition and functional properties of pennycress (Thlaspi arvense L.) seed protein isolates. Industrial Crops and Products. 55(1):173-179.
Interpretive Summary: In this research, we produced high-purity protein extracts (at least 90% protein content) from pennycress seed by using two methods (extraction with salt solution or by the conventional method) so that we may initiate the process of identifying and developing novel uses for the protein. Protein in pennycress seed meal is present in substantial amounts (about 27%) and could become the major co-product of processing pennycress oil, the highly promising alternative feedstock for biodiesel production. In our current work, we determined and compared the composition, amino acid profiles, and functional properties (solubility, foaming, emulsification, water-holding capacity, heat coagulability) of the resultant pennycress protein extracts from the two methods. We observed that extraction method had major influence on the nutritional quality and functional properties of the protein isolates. We found that pennycress protein had equivalent or better nutritional quality than soybean protein isolate. We noted that pennycress protein isolated using the salt solution was far more soluble and had superior emulsification properties than the protein isolated using the conventional technique. On the other hand, pennycress protein isolated using the conventional method had better foaming properties and was more stable to heating. Our results showed that pennycress proteins produced by either extraction routes have nutritional and functional properties that are desirable for both food and non-food uses (e.g., whipped or foam products, emulsions, or as nutritional supplement in juices).
Technical Abstract: This study evaluated two methods, saline extraction (SE) and conventional acid precipitation (AP), to recover proteins from pennycress (Thlaspi arvense L.) seed meal. SE was done using 0.1 M NaCl at 50ºC while AP involved alkaline extraction (pH 10) first followed by protein precipitation at pH 4. Composition, amino acid profiles, and functional properties (solubility, foaming, emulsification, water-holding capacity, heat coagulability) of the resultant protein extracts were compared. SE and AP produced pennycress protein extracts that were sinigrin-free and containing at least 90% (db) crude protein, which classifies the extracts as protein isolates (PI). Extraction method had major influence on the amino acid profiles and functional properties of the protein isolates. Pennycress APPI nutritional quality (amino acid scoring pattern) was superior to that of SEPI. However, SEPI was markedly more soluble (68-91% solubility at pH 2 and ' 7) and had excellent emulsifying properties that were clearly superior to those of APPI. On the other hand, APPI had better foaming properties and was more stable to heating than SEPI. These results strongly demonstrated that high-purity pennycress seed protein isolates can be produced by either saline extraction or acid precipitation and have nutritional and functional properties that are desirable for both food and non-food uses.