Location: Plant Polymer Research
2021 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
Under Objective 1, progress has been made on providing improved products from agricultural crops including corn. It has been estimated that up to 7% of the U.S. population may have gluten sensitivities. Developing new foods to provide an improved diet while avoiding gluten has great benefits. To achieve that, modified corn protein, zein, was evaluated. Improved gluten-free bread doughs have been produced using heat-treated zein. In our collaborative research with Purdue University, zein was heated in an oven (160 °C) before incorporating into dough. These gluten-free bread doughs exhibited increased strain hardening, which would deliver the desired level of rising. These results provide a new method for improving the quality of gluten-free bread.
Under Objective 1, progress has been made on providing an improved route to control crop-damaging nematodes using amylose inclusion complexes made from corn. Nematodes reduce crop yield by ~10% globally. Many traditional chemical treatments for nematodes are highly toxic and require sophisticated handling techniques. Developing a safe biobased treatment that can be easily produced and applied will have global value. Corn-based amylose inclusion complexes (AIC) continue to find value in protecting crops from pests; we evaluated their ability to control nematodes. AIC can be made from fatty amines and high amylose corn starch where no new chemical bonds are formed. Certain AIC were applied to tomato plants that were then exposed to pathogenic nematodes. The number of galls or number of nematode eggs were reduced by 62 and 75% respectively after AIC application. The tomato plants displayed no phytotoxicity with application of the AIC. The AIC performance was comparable to commercial nematicides. This research provides an environmentally friendly, biobased material to replace highly toxic nematicides and improve crop production.
Under Objective 1, progress has been made on developing high performance industrial emulsifiers and surfactants using amylose inclusion complexes made from corn. The surfactant and emulsifier market is valued at tens of billions of dollars and uses billions of pounds of petroleum-based chemicals. We have developed biobased alternatives that would provide a new use for farm products which would allow petroleum-based products to be used in markets that need their special attributes. AIC made using fatty amines (AIC-NH2) have shown value as emulsifiers and surfactants. For example, emulsified AIC-NH2/garlic oil systems are effective at controlling mosquito larvae. AIC-NH2 emulsified materials have very long shelf-lives, increasing their value-in-use. AIC-NH2 also make water ‘slicker’ (act as a surfactant), which allows the solution to penetrate parts and wet surfaces; these effects occur even more rapidly when the AIC-NH2 are made smaller. These AIC-NH2 products are also anti-microbial. The ability to make two materials form one phase, penetrate a complex part and kill microbes will have great value and they can compete with petroleum-based products.
Under Objective 1, progress has been made on providing higher value hydroxypropylmethylcellulose (HPMC) polymer films (possible use in food packaging) by blending HPMC with amylose inclusion complexes made from corn. In order to increase the value and expand the use of polymer films, polymer blends are often employed. If the polymer being added to the substrate is biobased and provides benefits, then the new product has increased market value and sustainability. When the fatty ammonium version of the AIC (AIC-NH2) are blended with HPMC, the blended films produced have higher value: they have antimicrobial properties (able to kill pathogenic bacteria and fungi) and they have more hydrophobic surfaces (repel water), which may open up new markets. In addition, the temperature at which the blended film fails is increased, which also allows them to compete with other film products.
For Objective 2, significant progress was made to develop methods for isolating proteins from new pennycress varieties and study their properties. Higher value farm crops that can grow over the winter months and be harvested in the spring will provide a new farm product and increased revenue to farmers without impacting current corn/soybeans production. One such crop is pennycress, a high oil, high protein winter annual. New pennycress-derived varieties with specialized traits (high protein/oil, low fiber, low erucic acid) are being developed to establish the plants as unique cover crops as well as cash crops for oil and protein. However, no research has been done to determine if agronomic breeding for these specialized traits translates to improved protein extractability and properties of protein or oil. Through a collaboration with CoverCress Inc., we developed protein extraction methods for new pennycress-derived varieties and assessed protein yield and properties. We adapted the saline-based extraction originally developed for wild pennycress which produced high purity protein concentrates from these new varieties. The isolated protein had high value, displaying high solubility, and forming substantial and stable foams. The pennycress protein also showed remarkable emulsifying activity. These results showed that protein from specialty pennycress can be extracted in good yield and with excellent properties.
For Objective 2, substantial progress was made to improve protein extraction techniques for maximizing the value of pennycress. The published bench-scale technique was simplified by removing numerous steps. Using this new technique, protein yield from pennycress press cake doubled, and product properties were equivalent or better than that of protein isolated using the previous lab method. While both extractions are commercially viable, the new improved process will have lower cost and higher value. This will increase the impetus for industry to scale-up protein production of this new crop.
Under Objective 2, notable progress was made to test high-power sonication (HPS, the use of sound waves to impart energy) as an alternative green technology for extracting plant proteins. Improved techniques for extracting plant proteins from various crops (such as lentil, green pea and soybean) are needed to maximize the amount and quality of the extracted protein. HPS is attracting much attention for extraction of plant-based proteins and modifying their functional properties. This technology can be coupled with heat-treatments of the seeds, which has also been known to impact protein extraction and value. Through a research collaboration with Iowa State University, we evaluated the impact of HPS and heat-treating seeds on protein extraction and properties. Heat treatment increased the protein content and value of the resulting pea and lentil flour. HPS reduced the oil content of the pea and lentil flour but did not affect their protein content. While soy flour compositions were not affected by either of the treatments, HPS did shorten the soy protein extraction time and increased protein yield. These results demonstrate that HPS and heat treatments were beneficial as pre-treatments for green pea, lentil and soy protein recoveries and properties, thus increasing the value of these crops.
Accomplishments
1. Improved process and yield for pennycress protein isolation. Pennycress grows as a winter crop, providing an additional revenue stream to farmers. Its oil is being developed as feedstock for biofuel. New and improved varieties (high protein/oil, low fiber) have been developed as a cover crop and a novel source of plant-based protein; however, no research has been done to determine if agronomic breeding for these specialized traits translates to improved protein extractability and market-valued properties. ARS researchers at Peoria, Illinois, developed protein extraction methods for new pennycress lines. The newly developed extraction method is a shorter process, doubled the yield and produced a soluble protein isolate with excellent foaming and emulsifying properties, thus increasing the value of recovered protein. These new protein products will increase value and acceptance of pennycress crops and subsequently benefit farmers, downstream processors, and consumers.
2. High-power sonication for improved plant protein extraction and properties. High-power sonication (HPS, using sound wave energy to enhance chemical and physical transformations) is a green technology that is generating high interest for use in extraction of plant-based proteins and modifying their functional properties. Through a research collaboration with Iowa State University, ARS researchers at Peoria, Illinois, evaluated the effects of two pre-treatments, HPS and heat (high temperature-short duration), on protein extraction from legumes (lentil, green pea and soybean flours) and on properties of the protein isolates. Heat treatments increased protein contents of green pea and lentil flours. HPS markedly reduced the oil content of green pea and lentil flours, but the protein contents were unchanged. These treatments did not affect the composition of soy flour; however, the extraction time was shortened, and protein yield was improved when HPS was employed. These results demonstrate that high temperature-short duration heating and HPS were beneficial pre-treatments for green pea, lentil and soy, given the improved protein recoveries and composition. This information will benefit downstream processors of legumes, which will contribute to higher revenue to all participants in the value-chain.
Review Publications
Byanju, B., Hojilla-Evangelista, M.P., Lamsal, B.P. 2021. Fermentation performance and nutritional assessment of physically processed lentil and green pea flour. Journal of the Science of Food and Agriculture. https://doi.org/10.1002/jsfa.11229.
Federici, E., Selling, G.W., Campanella, O.H., Jones, O.G. 2021. Thermal treatment of dry zein to improve rheological properties in gluten-free dough. Food Hydrocolloids. 115. Article 106629. https://doi.org/10.1016/j.foodhyd.2021.106629.
