Preparation and Properties of Solution Cast Films From Pennycress Protein Isolate

Abstract

This research evaluated a value-added use of pennycress protein by producing films and determining their properties. Pennycress (Thlaspi arvense L.) grows over the winter months, and is harvested in the spring. Pennycress seeds have high oil content and are a good candidate for biodiesel production. In order to extract the most value from pennycress, all parts of the seed must be utilized. An improved pilot-plant method for extracting protein from pennycress was developed providing a pennycress protein isolate (PPI) in high yield and purity (92% crude protein). Formic acid was found to be a good solvent for PPI and was used to produce transparent colored films. Glycerol (GLY) was found to be a good plasticizer for PPI, and films having between 10 and 30% GLY were produced. Higher GLY content resulted in films with an increase in elongation (up to 194%) but reduced tensile strength (TS) (from 21.8 to 3.2 MPa). With increasing relative humidity (RH), TS decreased and elongation increased. The glass transition temperature and heat deflection temperature for select PPI films were between 75-115 and 93-117 C, respectively. The films had relatively low water vapor and oxygen permeability. The overall balance of properties suggests that PPI films may have value in film applications, especially in composites where exposure to moisture may be minimized.

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).…”

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

“…They reported that, depending on the extraction method (saline‐based or conventional acid precipitation), WTP protein isolates were highly soluble (at least 76% soluble proteins) from pH 2 to 10, showed excellent foaming and emulsifying properties, and had high water‐holding capacities. Selling et al (2018) recently used WTP protein isolates to produce smooth and defect‐free cast films with low water vapor and oxygen permeability. These findings demonstrated that WTP protein may be used as an alternative protein source in pressurized or whipped foam products, emulsions, films, and other products in the rapidly expanding plant‐based protein market.…”