Location: Plant Polymer Research
2025 Annual Report
Objectives
Objective 1: Increase the value of amylose inclusion complexes (AICs) produced from various carbohydrates and ligands for use as emulsifiers, film blends or surface treatments for paper products.
Sub-Objective 1A: Develop effective emulsifiers based on AIC using high-amylose corn (HAC) or other polysaccharides, complexed with the salts of fatty acids or amines, using economical manufacturing techniques.
Sub-Objective 1B: Produce higher value polymer blends or cellulosics using amylose inclusion complex materials made with lower-cost starches, such as normal corn food-grade starch (FGS) or corn flour, and fatty acids/amines or their salts.
Objective 2: Resolve the underlying lab and pilot-scale extraction and biorefining techniques that generate protein-rich industrial feedstocks from plant crops, such as camelina or sorghum, define their functional properties, and enable industrial production and commercialization.
Approach
This project plans to increase the value of existing and new crops by developing higher value amylose and protein products. Recent research has shown that starch processed from corn can provide high-value amylose inclusion complexes with vegetable oil derivatives (ex. fatty acid or amine salts) in excellent yield and at low cost. To transfer this technology to industry, it is critical to determine the impact of the amount and source of amylose on the attributes of the resulting complex. Protein-rich crops such as camelina or sorghum, which are not produced in high quantities in the U.S., have the potential to provide additional higher revenue streams to U.S. farmers. While the U.S. is the world’s leader in sorghum production, the use of sorghum is currently generally relegated to feed uses. Given the similarities between sorghum and corn, it is expected that sorghum value can be increased by utilizing its component fractions, as has been done to corn. Camelina has shown value as a winter-grown oilseed crop, but new uses are needed for the components of the resulting seed press cakes. Improved extraction techniques are needed to increase the value of both crops. This research will: 1) enable new approaches to produce and use amylose complexes and establish their physicochemical properties, and 2) innovate and evaluate extraction techniques, as well as identify uses for proteinaceous materials from crops such as sorghum and camelina. Improved utilization of current and future crops will enhance the value of these crops in new and existing markets.
Progress Report
This report summarizes progress for this project that began April 13, 2020, and ended April 12, 2025. Research will be continued under the new project 5010-30600-001-000D, “New and Improved Plant-Based Polymers.”
In support of Objective 1, significant progress was made towards commercializing a corn-based product called amylose inclusion complexes (AIC) developed by ARS scientists in Peoria, Illinois. This product is formed by binding amylose, a type of starch, with food-safe vegetable oil derivatives (e.g., fatty acids) using a common steam jet cooking process in the food industry. This production method was optimized to nearly 100% yield using commercially available corn starch and vegetable oil derivatives. The AIC obtained were found to have outstanding emulsifier and surfactant properties that make them valuable for numerous agricultural and food applications. Emulsifiers are used to stabilize liquids that don’t normally mix (e.g., oil and water in salad dressing or paints) into one blended product, while surfactants also help with mixing but are more focused on cleaning and personal care products. AIC showed comparable performance with silicone-based surfactants, thus providing a more biodegradable biobased alternative for emulsifying and wetting applications, such as spray cleaners. Materials emulsified using AIC have very long shelf-lives and superior performance to commercial emulsifiers made with starch, guar gum, or soy protein. They are also less toxic and have reduced environmental impact. Use of corn-based AIC instead of the current commercial emulsifiers/surfactants will help corn farmers supply a $10.5 B emulsifiers global market or a $45.6 B surfactants global market.
To develop cost-effective AIC with properties specific to the desired applications, the research team utilized vegetable oil derivatives from non-traditional oil sources. In collaboration with other ARS scientists in Peoria, Illinois, they successfully produced AIC using derivatives of oils from camelina, coconut, coriander, citrus, cuphea, hemp and meadowfoam, with production yields between 92-96% yield. These AIC have good surfactant properties regardless of composition and performed comparably to surfactants prepared from AIC with higher-priced purified vegetable oil derivative. In addition, the team examined the performance of AIC made with the less expensive starch from normal corn, waxy corn, potato, and sorghum. The prior work on AIC used high amylose corn starch, a special grade, but pricier, corn starch. All the less expensive starch sources were able to produce AIC that showed similar surfactant and emulsifier properties. AIC made with starch from waxy corn, normal corn or sorghum produced substantial and stable foam, which is useful for pressurized foam products. These results showed AIC can be prepared with inexpensive and more commonly available starch or vegetable oil derivatives to generate a product that performs as well as food grade emulsifiers and surfactants.
This ARS research team also found that certain AIC emulsions are potent antimicrobial agents and pesticides. AIC were able to effectively eliminate numerous fungal plant pathogens and bacterial animal pathogens. AIC emulsions with garlic oil effectively controlled mosquito larvae, while an AIC emulsion with pinewood oil was a very effective termiticide, killing 100% of termites exposed to treated wood. AIC were effective in killing nematodes (a class of plant pests) in tomato plants at a rate comparable to more toxic commercial nematicides. This work provides farmers and consumers with new biobased alternatives to replace highly toxic fungicides and pesticides for improved crop production. Overall, the corn-based AIC products developed from this research will open new markets that will help improve farm incomes and broaden economic opportunities in rural communities.
In support of Objective 2, substantial progress was made on enhancing methods to isolate and purify plant-based proteins from non-traditional sources. Plant-based proteins play an important role in food/protein security and are in high demand for the diversified protein markets. They are also commonly used in food applications requiring foaming and emulsification properties, such as meat binders and baked goods. Similarly important, non-traditional crops are a key component of agriculture for diversification, soil health, pest reduction, and enhanced food security. However, improved techniques for extracting proteins from agricultural crops are needed to maximize the amount and quality of the protein product. ARS researchers in Peoria, Illinois developed methods for isolating proteins from camelina and pennycress, which are both winter annual crops (i.e., planted in late fall) rich in oil and protein that can serve as opportunities for new farm products. These crops provide increased revenue to farmers without impacting current corn/soybean production. This work first focused on new pennycress varieties with specialized traits (high protein and oil, low fiber, improved color) developed to establish the plants as unique cover crops and cash crops for protein and oil; however, no research had been done to determine if agronomic breeding for these specialized traits translates to improved protein extraction and properties. Through a funded collaboration with an industry partner, ARS researchers developed a simplified extraction technique based on the method previously used for wild-type pennycress. This improved method doubled protein yield and produced protein products with better solubility, foaming and emulsification than the isolates obtained by the previous lab method. The team then developed environmentally desired methods for isolating proteins from two new golden pennycress varieties (TT8 and TTG1), which were nearing commercial planting. This improved process, which employed alternatives to petroleum-based defatting solvents to better align with consumer preferences for ‘clean’-labelled products, produced high-purity (85-95%) protein isolates from both varieties. TT8 had much greater protein recovery and purity than TTG1 and produced a more soluble isolate with superior foaming and emulsification properties. Highly soluble proteins are usually preferred by industry, given that protein solubility affects other functional properties. The golden pennycress protein isolates show potential use in whipped dairy products, dairy beverage alternatives, protein shakes, yogurt, salad dressings, baked goods, shaving creams, foamed glues, and paints. The new improved processes will increase the impetus for industry to scale-up protein production of this new crop and help pennycress farmers supply a $23.0 B diversified plant protein market.
This group of ARS scientists also developed and assessed protein extraction methods for sorghum. Sorghum is a high-volume, heat- and drought-resistant ancient grain that is primarily used as animal feed and for ethanol production. Current interest in sorghum is a result of the steep growth of new plant-based protein markets. Sorghum’s major proteins have posed challenges for extraction yield and protein quality when using conventional methods, so improved processes are needed to extract a unique mixture of sorghum protein fractions that may have novel or enhanced traits. In this project, the team developed a method that yielded high protein recoveries (78-83%) and produced high-purity (87-97%) protein extracts. The protein isolate from pearled sorghum (outer bran layer removed) was notably lighter colored than the protein product obtained by wet milling process where the sorghum grain is soaked in water, then ground and separated into its main components of starch, fiber and protein. Protein isolates of the pearled sorghum samples had five-fold greater solubility than the isolate of wet-milled sorghum protein meal. All sorghum protein isolates produced substantial foam. The pearled sorghum protein isolate showed superior emulsification properties to those reported for soy protein isolate. Scaled-up protein extraction from over six pounds of pearled sorghum had 90% protein recovery and produced a protein isolate with similar high purity and functional properties as the lab-scale method. This work showed that this new extraction method significantly enhanced yield, solubility, and emulsifying ability of sorghum protein.
Lastly, the team determined the effects of seed maturity and variety of agricultural hemp on protein quality. Through a collaboration with a university and other ARS scientists in Peoria, Illinois, they analyzed hemp seeds from Henola variety for protein extractability, soluble protein classes, and protein size. Protein recovery from mature seeds was greater than that from immature seeds. Seed maturity notably affected the solubility of different protein groups. Water-soluble proteins were abundant in immature hemp seeds, while proteins soluble in basic solutions (like diluted lye) are dominant in mature seeds. Additionally, they analyzed 16 new and established varieties of hemp grain provided by an industry partner for differences in soluble protein classes and protein recovery. Total protein content among varieties was similar and within a narrow range, 24-27%; however, the amount of each soluble protein class varied greatly. This work demonstrated the notable effects of seed variety and maturity on the amount of each soluble protein group, which will impact the method of hemp seed protein extraction and subsequent yield.
This research project developed novel products and uses from important agricultural crops. The new products will provide additional revenue streams for corn, pennycress, sorghum, and oilseeds crops, and subsequently benefit farmers, downstream processors, consumers and the environment.
Accomplishments
1. Enhanced production and value of sorghum protein. Sorghum is an important U.S. agricultural crop because of its drought tolerance, reduced input costs, and high protein and starch contents. Sorghum is used mainly as animal feed and for ethanol production, but sorghum growers could benefit from expanded use in foods. This has been limited because sorghum protein is difficult to purify and incorporate into foods. ARS scientists in Peoria, Illinois, developed an effective method for extracting high-purity sorghum protein with high yield. This process produced protein with desired properties for use in food products, such as yogurt, dairy alternative beverages, salad dressings, gluten-free baked goods, and meat substitutes. In addition, sorghum protein extracted via this approach can also be used in industrial applications, such as wood adhesives. The new protein products serve as an additional revenue stream for sorghum, will increase the crop’s value, and will subsequently benefit farmers, downstream processors, consumers, and the environment.
Review Publications
Evangelista, R.L., Hojilla-Evangelista, M.P., Gesch, R.W., Cermak, S.C., Isbell, T.A. 2024. Aqueous fractionation of mucilage and protein from Camelina sativa seeds and defatted meal. Industrial Crops and Products. https://doi.org/10.1016/j.indcrop.2024.119560.
Jackson, M.A., Selling, G.W., Evans, K.O., Wegener, E.C. 2024. Cuphea as a source of fully crop-based plasticizers for Poly(vinyl chloride). ACS Sustainable Chemistry & Engineering. https://doi.org/10.1021/acssuschemeng.4c01592.
Liu, K., Seegers, S., Hojilla Evangelista, M.P., Pallares, A.P., Wu, X. 2024. International collaborative study on measuring protein solubility index for legumes, oilseeds, cereals, and related products. Sustainable Food Proteins. 2(4):236–249. https://doi.org/10.1002/sfp2.1039.
Selling, G.W., Kenar, J.A., Cermak, S.C., Hojilla-Evangelista, M.P., Hay, W.T., Utt, K.D., Chisholm, B.J. 2025. Characterization and emulsification properties of amylose inclusion complexes prepared from corn starch and plant oil derived fatty acid sodium salt mixtures. Carbohydrate Polymer Technologies and Applications. https://doi.org/10.1016/j.carpta.2025.100682.