Cold-pressing, ethanol defatting, and saline extraction enhances properties of protein products from new pennycress varieties (covercress)

Authors: Hojilla-Evangelista, Milagros - Mila; Evangelista, Roque; Selling, Gordon; ULMASOV, TIM - Covercress, Inc

Submitted to: Sustainable Food Proteins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2024
Publication Date: 4/15/2024
Citation: Hojilla-Evangelista, M.P., Evangelista, R.L., Selling, G.W., Ulmasov, T.N. 2024. Cold-pressing, ethanol defatting, and saline extraction enhances properties of protein products from new pennycress varieties (covercress). Sustainable Food Proteins. https://doi.org/10.1002/sfp2.1029.
DOI: https://doi.org/10.1002/sfp2.1029

Interpretive Summary: Pennycress is a winter crop that is being cultivated as an off-season cash cover crop (for biofuel and protein) that will provide an additional revenue stream to farmers while also increasing the soil quality. New and improved pennycress varieties have been developed as a novel source of plant-based protein; but research is needed to assess their protein extractability and the functionally important properties of these proteins. In this research, we developed and evaluated an environmentally friendly method for extracting protein from two new golden pennycress lines (TT8 and Y1126, low fiber/high oil/high protein). Our process, which involved cold pressing, ethanol defatting, and saline extraction of protein, generated high purity protein products. We recovered much more protein from TT8 press cake than from Y1126 press cake. We found that the TT8 press cake protein was more soluble in acidic media (like whey protein) and had superior foaming properties; however, the protein from both new varieties showed improved functional properties over those of wild type pennycress protein. These results demonstrated that high purity protein with enhanced properties can be isolated from specialty golden pennycress by using this newly developed environmentally friendly and industrially relevant protein isolation method. The enhanced solubility and foaming properties are useful in dairy alternatives, fruit juices, whipped toppings, and baked products, thus increasing the value of the protein product and the crop.

Technical Abstract: Pennycress (Thlaspi arvense L.), a winter oilseed and cover crop, is a source of novel proteins and oil for biofuel. New yellow-seeded pennycress specialty varieties, named covercress, were developed via conventional breeding and gene editing, but protein characteristics are still unknown. This work evaluated two covercress lines, TT8 and TTG1/Y1126, for protein extraction and functionality, and the combination of cold-pressing, alcohol-defatting and saline extraction to produce protein that aligns better with clean labeling. Seeds were first cold-pressed in a tubular radial expeller then defatted at 60°C with anhydrous ethanol (Eth) or hexane (Hex) until = 0.8% residual oil. Protein was extracted from defatted press cake (PC) using saline method (0.1 M NaCl, 1: 10 w/v, 50°C, 2 h) for wild-type pennycress (WTP). TT8 PC had 33-67% more globulin and glutelin than WTP PC, but ethanol defatting reduced albumin + globulin amounts by 14-32%. TT8 PC protein recoveries (63 and 40%) were 2- to 3-fold greater than that of Y1126 PC-Eth and their extracts had greater purity (85-91 versus 70% protein). Y1126 PC-Eth protein showed a nearly constant 68-70% solubility from pH 2-10, but TT8 PC-Eth protein was more soluble in acidic pH (87-90% solubility). Y1126 PC-Eth protein showed greater foaming capacity (146-150 ml), while TT8 PC-Eth protein had superior emulsifying properties (EAI 141-236 m2/g protein and ESI 13-26 min). This work demonstrated the enhanced functionality of TT8 and Y1126 proteins produced from an environmentally friendly and industrially relevant method.