Location: Plant Polymer Research
2021 Annual Report
Objectives
Objective 1. Enable new food-contact active packaging and coating materials through selective chemical modification and novel processing techniques.
The focus of Objective 1 is to design new food packaging materials from biobased and renewable-sourced polymers using novel physical processes and chemical modifications. The products will protect and enhance food products, eliminate or reduce pathogens, address antimicrobial resistance, extend shelf-life, and reduce food waste and food poisoning incidents.
Objective 2. Enable commercialization of new agro-based value-added green products and processes.
Objective 2 utilizes renewably sourced polymers, polymer blends, modified polysaccharides, and bio-oils to provide high-value products using state-of-the-art chemical and physical techniques, such as microwave processing, reaction chemistry and separations in ionic liquid and deep eutectic solvents, reactive extrusion, electrospinning, electrospraying, and nanotechnology. Through Objective 2, we envision the development of new or improved biopolymers made from agro-based raw materials targeted for plastic replacements (biodegradable polymers and plasticizers), adhesives (melt and pressure sensitive), personal care and cosmetics (dispersants, emulsifiers, bioactive agents), biobased phase change materials for thermal insulation, energy storage and conservation, and specialty materials (coatings, thickeners, adsorbents, metal ion sequestrants, flocculants, and catalyst supports).
Moreover, this project will yield modified industrial and commercial processing methods that will increase the efficiency and lower the cost for replacement of similar non-renewable polymer products. Polymeric materials from renewable resources will provide environmental benefits over materials currently in use. New fundamental knowledge of the interactions of plant-based carbohydrates with additives and polymers will provide the basis for a rational design of novel agro-based materials with targeted properties. See Appendix 1A for a flow diagram of the project.
Approach
The main outcome of this project is to develop environmentally friendly green processes and products by adopting circular bio-economy strategies. The first objective is to design new food packaging materials from biobased and renewable-sourced polymers using novel physical processes and chemical modifications. These packaging materials are intended to protect and enhance food products, promote food safety, eliminate or reduce pathogens, extend shelf-life, address antimicrobial resistance, reduce food waste and lead to greater availability of food to human, animal, and plant life. Active packaging materials will reduce the number of pathogens in food and food products through controlled release mechanisms. The second objective utilizes agro-based polymers, polymer blends, modified polysaccharides, and triglycerides (including sorghum and hemp oils) to develop high-value products using state-of-the-art chemical and physical techniques, such as microwave processing, ionic liquid and deep eutectic solvent reactions and separations, reactive extrusion, electrospinning, electrospraying, and nanotechnology. Overall, the project will develop agro-based polymer products that have new or improved properties at lower cost, have reduced environmental footprint, and are responsive to evolving consumer markets. The project will also generate innovative technologies, thereby enabling new market opportunities for agricultural products to replace polymeric materials based on non-renewable resources. This research will widen the application boundaries of agriculture, thereby increasing the demand, value, and utility of agricultural commodities.
Progress Report
Under Objective 1, we are waiting to fill up the 1.3 SY vacant positions to address the milestones.
Under Objective 2, significant progress was made to produce pyrodextrins from breadfruit starch. After cellulose, starch is the most abundant polysaccharide in plant cells. It is often modified to enhance its performance in different applications. One type of modification is pyrodextrinization, involving the use of heat or a combination of heat with an acid catalyst (reaction accelerator). Breadfruit (Artocarpus altilis) is a tropical fruit and an unconventional but excellent source of starch. ARS researchers at Peoria, Illinois, in collaboration with researchers from Brazilian Agricultural Research Corporation (Embrapa), Fortaleza, Brazil, extracted breadfruit starch to produce pyrodextrins. We evaluated the effects of two mineral acid catalysts (hydrochloric acid and glacial acetic acid) on specific physicochemical and structural properties of pyrodextrins. Heat-aided conversion of starch was achieved by spraying the acid solution over the powdered starch, which was then reacted in a 140 °C-oven for 180 min. The use of acetic acid, considered a milder treatment, caused a slight increase in the total and soluble fiber contents, which can be advantageous for the production of soluble and less viscous dietary fibers for food applications. It is well documented in literature that pyrodextrins are indigestible and are a good source of resistant starch, comparable to dietary fiber. Thus, pyrodextrins obtained from breadfruit may be helpful for diabetics and can be used as functional ingredients in dairy products, sauces, and soups.
Under Objective 2, notable progress was made on developing hemicellulose as a coating agent for medicinal-related application. A major opportunity to enhance the value of plant biopolymers is the therapeutic field, particularly those uses involving the confluence of agro-based materials, nanotechnology, and biomedical applications. In a collaborative effort with ARS researchers at New Orleans, Louisiana, and Brazilian researchers from Embrapa, Fortaleza, Brazil, we extracted hemicellulose, a component of plant cell walls, from Caesalpinia pulcherrima plant, a common plant known to have medicinal properties. The hemicellulose was then used to coat iron oxide nanoparticles. The resulting coated materials have maintained the iron oxide’s tiny structures (nanostructure) and were non-toxic. This material is considered a candidate for fluid magnetic hyperthermia in cancer treatment through targeted delivery of the nanoparticles that are then heated to kill cancer cells. This promising approach of using hemicellulose and other related plant biopolymers in modified coating procedures opens the possibilities for the design of new nanoparticles for tissue engineering and other biomedical applications.
Accomplishments
1. Use of cashew gum as an encapsulating agent to extend the shelf life of food or bioactive ingredients. Encapsulation provides significant protection against degradation caused by air and heat, thereby contributing to longer shelf life of the encapsulated ingredients. Encapsulation of drugs and food ingredients is often needed for many applications to provide controlled release and improve their stability and properties. Because of the broad utility of encapsulation, new encapsulating (wall) materials and improved methods for encapsulation are always desirable. Cashew gum, a byproduct from cashew nut production, is a widely available agro-based raw material to produce eco-friendly and biodegradable polymers. ARS researchers at Peoria, Illinois, and collaborators from the Institute of Agrochemistry and Food Technology (IATA) at Spanish National Research Council, Valencia, Spain, used cashew gum polysaccharide to encapsulate ß-carotene (a precursor that converts to vitamin A in the body) through the method of electrospraying. The encapsulated carotene was shown to be significantly protected against air (oxygen)-induced degradation. Thus, the combination of cashew gum polysaccharide (as the wall material) and electrospraying (as the encapsulation method) can be a good method for encapsulation purposes in food and pharmaceutical applications resulting in a longer shelf life.
2. Conversion of xylan to industrial chemicals with higher value. Xylan is a type of hemicellulose (a structural material) that is found in most plants. Despite broad availability, xylan is under-utilized because it does not have the end-use properties needed for various applications. Thus, it would be desirable to modify xylans to broaden their applicability and increase their value. ARS researchers at Peoria, Illinois, and New Orleans, Louisiana, have modified xylan with various water-repelling chemicals. The modified xylans that were produced display properties that can be useful for products such as detergents, fabric softeners, and thickening agents for flow control of paints, inks, or cosmetics.
3. Environmentally friendly “green” plastics as packaging materials. Polyhydroxyalkanoates (PHA) are considered promising “green” alternatives to petroleum-based synthetic polymers (for example, nylon, polyethylene, and polyester that are currently used to make plastics) because they are made by bacteria and are biodegradable and biocompatible with living tissues. They have similar properties as plastics with good moisture/aroma transport properties but are relatively brittle and stiff. However, a mixed polymer called poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is less stiff and tougher, making it ideal for packaging material. Its properties depend on composition, which can be analyzed by a technique called nuclear magnetic resonance (NMR). ARS researchers at Peoria, Illinois, devised an improved NMR method for PHBV structure determination that provides more accurate structural information about PHBV. This knowledge helps us to understand the structure-property relationships, which we can use for making better PHBV plastics for specialty packaging, orthopedic devices and in controlled release of drugs.
Review Publications
Krishnani, K.K., Choudhary, K., Boddu, V.M., Moon, D.H., Meng, X. 2021. Heavy metals biosorption mechanism of partially delignified products derived from mango (Magnifera indica) and guava (Psidium guiag) barks. Environmental Science and Pollution Research. 28:32891-32904. https://doi.org/10.1007/s11356-021-12874-1.
Vazquez-Gonzalez, Y., Prieto, C., Filizoglu, M.F., Ragazzo-Sanchez, J.A., Calderon-Santoyo, M., Furtado, R.F., Cheng, H.N., Biswas, A., Lagaron, J.M. 2021. Electrosprayed cashew gum microparticles for the encapsulation of highly sensitive bioactive materials. Carbohydrate Polymers. 264:118060. https://doi.org/10.1016/j.carbpol.2021.118060.
Cheng, H.N., Biswas, A., Kim, S., Alves, C.R., Furtado, R.F. 2021. Synthesis and characterization of hydrophobically modified xylans. Polymers. 13:291. https://doi.org/10.3390/polym13020291.
Cheng, H.N., Biswas, A., Furtado, R.F., Alves, C.R., Wu, Q. 2020. Design and evaluation of agro-based food packaging films. In: Cheng, H.N., Gross, R.A., editors. Sustainability & Green Polymer Chemistry Volume 2: Biocatalysis and Biobased Polymers. ACS Symposium Series, Vol. 1373. Washington, DC:American Chemical Society. 1373:193-204. https://doi.org/10.1021/bk-2020-1373.ch011.
Cheng, H.N., Biswas, A., Vermillion, K., Melendez-Rodriguez, B., Lagaron, J.M. 2020. NMR analysis and triad sequence distributions of poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Polymer Testing. 90:106754. https://doi.org/10.1016/j.polymertesting.2020.106754.
