Extraction and properties of proteins in covercress™, new pennycress varieties developed as cover crop and alternative plant protein source

Abstract

Pennycress (Thlaspi arvense L.) is a winter oilseed crop that also functions as cover crop, oil feedstock for biofuel, and novel plant-based protein. New pennycress specialty varieties were developed by conventional breeding techniques, but protein chemical and functional traits are still unknown. This research evaluated three new lines (black-seeded B3 and yellow-seeded TTG1/Y1126 and TT8) for protein extractability and functionality. Seeds were ground cryogenically and then hexane-defatted until residual oil content was 0.5%-0.7% dry basis, db. Protein in defatted seed meals was extracted using saline method (1: 10 wt/vol, 0.1 M NaCl, 2 h, 50 C). TT8 and Y1126 had greater protein recoveries (ca. 50%) than those of B3 (36%) and wild-type pennycress (WTP, 40%). TT8 produced higher purity protein isolate (94.3%) than did Y1126 (75.0%) and B3 (71.3%). TT8 and Y1126 protein band patterns were different from WTP and B3, reflecting varietal changes. The new varieties' protein extracts were more soluble than WTP protein in acidic pH, with TT8 showing the highest solubility (81%-93%). TT8, Y1126 and B3 foaming capacities (113-135 ml) were superior to those of WTP (101-107 ml). Emulsification properties (EAI 95-230 m 2 /g protein, ESI 13-24 min) were similar and increased with pH. B3, Y1126, and TT8 formed heat-induced gels at much lower concentration than did WTP (3% vs. 6%) and their water-holding capacities (pH 7) were two to fivefold greater. This work demonstrated that mutations in the TTG1 or TT8 gene in yellow-seeded lines resulted in improved protein recoveries and functionalities that are desirable in plant-based proteins. K E Y W O R D S emulsification, pennycress, protein extraction, protein foams, protein solubilityThis research was supported by the U.S. Department of Agriculture, Agricultural Research Service. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer.

Pennycress domestication and improvement efforts

“…Researchers at USDA ARS in Peoria, Illinois, developed extraction methods producing 90%–97% crude protein successfully from wild‐type pennycress (Hojilla‐Evangelista et al., 2013, 2014, 2015). The extracted pennycress protein compared well with soybean/canola protein attributes with excellent emulsifying, foaming, and water‐holding capacities validated by another independent research effort (Hojilla‐Evangelista et al., 2023; Selling et al., 2018). Using advanced genomics and a translational approach, CoverCress pennycress was developed by private industry with low fiber, high protein, and high oil pennycress cultivars using TTG1 or TT8 mutant lines (Hartnell et al., 2022).…”

“…Researchers at USDA ARS in Peoria, Illinois, developed extraction methods producing 90%-97% crude protein successfully from wild-type pennycress (Hojilla-Evangelista et al, 2013, 2014. The extracted pennycress protein compared well with soybean/canola protein attributes with excellent emulsifying, foaming, and waterholding capacities validated by another independent research effort (Hojilla-Evangelista et al, 2023;Selling et al, 2018).…”

“…These newly developed pennycress cultivars mediate the expression of several genes in seed‐altering protein, oil, and fiber composition. More recently, the chemical and functional properties of CoverCress pennycress were evaluated, where the protein was superior in terms of extractability, purity, recovery, solubility, foaming, foam stability, and water‐holding capacities when compared to the black seeded wild type (Hojilla‐Evangelista et al., 2023). Among all the mutants, TT8 pennycress had the desirable attributes with potential uses as a dairy substitute and in a wide range of bakery products (Hojilla‐Evangelista et al., 2023).…”

“…More recently, the chemical and functional properties of Cov-erCress pennycress were evaluated, where the protein was superior in terms of extractability, purity, recovery, solubility, foaming, foam stability, and water-holding capacities when compared to the black seeded wild type (Hojilla-Evangelista et al, 2023). Among all the mutants, TT8 pennycress had the desirable attributes with potential uses as a dairy substitute and in a wide range of bakery products (Hojilla-Evangelista et al, 2023). Tandukar et al (2022) conducted a comprehensive GWAS on a diverse pennycress germplasm, identifying significant SNPs and candidate genes governing several traits.…”