Location: Plant Polymer Research
2022 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
Objectives 1 and 2. Essential oils (EOs) are extracts from flowers, seeds, and other plant parts, often used as fragrance, flavors, and antimicrobial ingredients. One strategy for the incorporation of EOs into agro-based materials is to use microencapsulation, a process where tiny particles or droplets are surrounded by a micro-coating to give small capsules. These capsules often have beneficial properties such as serving as delivery systems for active components in food, agricultural, and medical applications. For food applications, the coating material must be food-grade. The choice of a suitable coating material is very important, and new or improved core/coating combinations are always being sought.
Under Objectives 1C and 2B, ARS researchers in Peoria, Illinois, evaluated pequi essential oil extracted from the seeds of the Caryocar brasiliense, which is native to Brazil and reputed to be beneficial to human health. Through a research collaboration with the Brazilian Agricultural Research Corporation, ARS researchers in Peoria, Illinois, have developed a microencapsulation technique to use cashew gum, a novel polysaccharide, to coat pequi oil. The resulting capsules have been incorporated in yogurt formulations, and the optimal process conditions for such incorporation have been determined. The materials and the methodologies used for this work may be adapted to other pertinent food systems in the future. This technology will have value in pharmaceutical, agrochemical, and food industries.
Objective 2. Polylactic acid (PLA) is a common biobased film-former made from renewable biomass, such as corn, sugarcane, or cassava. There have been prior efforts to make packaging films from PLA, but PLA is relatively expensive.
Under Objective 2A ARS researchers in Peoria, Illinois, have sought to produce a new type of PLA film by incorporating cottonseed meal (CSM), an inexpensive protein-rich raw material from cotton manufacturing. Both PLA and CSM are agro-based, sustainable, and biodegradable. Direct mixing of PLA and CSM was difficult because they did have not mutual solvents and the two materials were not easily compatible. ARS researchers in Peoria, Illinois, resolved this issue by devising a novel blending technique for PLA and CSM that produced bilayer films. CSM and PLA were each dissolved in appropriate solvents and then bilayer films were created by casting the PLA solution layer on top of a CSM film. The combined thickness of the PLA/CSM bilayer film was between 80 and 120 micrometers, of which the PLA layer accounted for 10%, 30% or 50% of the total bilayer film’s thickness. Mechanical properties, opacity, water vapor permeation, and thermal and microscopic properties of the films demonstrated that the bilayer films can be made and used as biodegradable films. The 50% sample had the best balance of properties. This research developed a new kind of film which will benefit food packaging film manufacturers and reduce plastic waste and microplastics. Moreover, the utilization of cotton by-product CSM for this higher value applications will mean more profit for U.S. cotton farmers.
Lactose is an inexpensive natural sugar derived from whey, a byproduct of cheesemaking and casein production. In order to further add value to the whey/lactose, they could be converted into industrial chemicals via polyurethanes chemistry.
Under Objective 2B, ARS researchers in Peoria, Illinois, demonstrated that lactose polyurethanes could be made with both conventional and microwave heat, and the products had similar yields and chemical structures. Moreover, the microwave reaction represents a “green chemistry” process, where no catalyst (reaction accelerator) was used, and the microwave reaction took only three minutes at 145 degrees C. In contrast, conventional heating took 20 minutes. The product was a free-flowing liquid, a viscous liquid, a gel, or a solid, depending on the toluene-2, 4-diisocyanate/lactose ratio. The ARS researchers in Peoria, Illinois, also made semi-interpenetrating polymer network (SIPN) with the lab generated lactose polyurethane by embedding polylactic acid (PLA) and polyvinylpyrrolidone (PVP) into the lactose polyurethanes. Other polymers may also be incorporated into lactose polyurethanes with this SIPN methodology. As PLA and PVP are often used in biomedical applications, these novel lactose-based materials may also be considered for similar uses. By developing new uses for milk co-products dairy farmers will benefit.
Accomplishments
1. Produced environmentally friendly bioplastic from lactose. In view of growing public awareness of environmental pollution, plastic waste, and microplastics, agro-based materials are increasingly used to replace raw materials derived from fossil feedstocks to take advantage of their sustainability, eco friendliness, better recyclability, and lack of toxicity. ARS researchers in Peoria, Illinois, have utilized sugars and polysaccharides to produce new biodegradable and sustainable bioplastics. In a recent study, they used lactose, a cheap and widely available sugar derived from whey, a byproduct of cheesemaking and casein production. They synthesized polyurethanes from lactose by devising a green process with microwave heating that did not involve toxic catalysts (reaction accelerators). Microwave heating was found to reduce the reaction time and save energy relative to conventional heating. Moreover, the properties of the lactose-based polyurethane can be improved by mixing in a second polymer. The new materials may be used as bioplastics in biomedical applications replacing polymers made from petroleum-based materials and providing added value to the dairy industry.
Review Publications
Oliveira, E.D.S., Lovera, M., Pires, V.R., Mendes, F.R.D.S., Maia, N.V.L.P., Rodrigues, J.P.V., Bastos, M.D.S.R., Cheng, H.N., Biswas, A., Moreira, R.D.A., Moreira, A.C.D.O.M. 2022. Effect of acid catalyst on pyroconversion of breadfruit (Artocarpus altilis) starch: Physicochemical and structural properties. Journal of Food Processing and Preservation. 43(3). Article e16408. https://doi.org/10.1111/jfpp.16408.
Cheng, H.N., Biswas, A., Kim, S., Appell, M., Furtado, R.F., Bastos, M.S.R., Alves, C.R. 2022. Synthesis and analysis of lactose polyurethanes and their semi-interpenetrating polymer networks. International Journal of Polymer Analysis and Characterization. 27(4):266-276. https://doi.org/10.1080/1023666X.2022.2064037.
Da Silva, L.C., Castelo, R.M., Magalhaes, H.C.R., Furtado, R.F., Cheng, H.N., Biswas, A., Alves, C.R. 2022. Characterization and controlled release of pequi oil microcapsules for yogurt application. LWT - Food Science and Technology. 157. Article 113105. https://doi.org/10.1016/j.lwt.2022.113105.
