Progress 09/01/05 to 08/31/07
Outputs
OUTPUTS: We improved and demonstrated enzyme-assisted aqueous extraction processing (EAEP) can be used to recover oil from soybeans and to produce an enzyme-modified soy protein (EMSP) product for use in wood product adhesives. EAEP is a water-based process to replace hazardous, polluting and petroleum-derived hexane. Chemicals used in wood adhesives are expensive and hazardous to workers. Our most significant findings for EAEP are: 1. we evaluated various mechanical and thermal processes having potential to improve oil extraction, but extrusion remained the best; 2. conditions for optimal oil extraction from unextruded soybean flour were detrimental to demulsifying the oil-containing cream; 3. kinetic data on enzyme action can be used in models to examine the interaction of enzyme dosage, hydrolysis time, oil and protein extraction and to identify oil-release mechanisms; 4. microscopy correlated hard-to-release oil with intact cells; 5. protein fractions obtained by acid
precipitation of skim milk contained 69 to 92 percent protein and 10 to 20 percent oil, and little residual trypsin inhibition activity, indicating good feed value; 6. the cream resulting from EAEP was oil associated with significant amounts of large proteins and some lecithin; 7. we identified three ways to de-emulsify the cream to enable oil recovery; 8. we were able to sequentially dismantle soybean cells, isolating as much as 47% of the oil as intact oil bodies that may have high value uses in foods and pharmaceuticals by using a sucrose floatation centrifugation procedure with enzymes; 9. reducing agents to treat unheated soy flour gave better digestibility for animals. Our most significant findings for EMSP are: 1. we successfully scaled-up the enzyme process to produce ESMP in the pilot plant using 5- and 50-gal tanks; 2. we assisted a farmer-owed cooperative adopt the process at 100-gal level; 3. we produced EMSP using a combination of different enzymes to make it more worker
friendly and easier to process than using more hazardous and costly alkaline hydrolysis; 4. ESMP could replace up to 20% of the petroleum-based chemicals adhesive formulations; 5. we could tailor ESMP for specific adhesive formulations used in different applications by making a variety of viscosities for different adhesives. Our results were presented at the annual meeting of the American Oil Chemists Society. Our industry partner, Genencor International, is a world leader in enzymes and enzyme technologies, and manufactures enzymes that are key to making soy protein adhesives and the EAEP process work. They provided access to their enzyme library and supplied enzymes. We have held semi-annual progress reviews with Genencor to keep them abreast of all scientific discoveries. They have met with others in the oilseeds processing industry to begin to develop commercial interest and identify potential roadblocks. We filed a U.S. patent on an invention for de-emulsifying the oil-rich
cream, which is a critical step in recovering food oils. We demonstrated that EMSP is an effective wood adhesive. A farmer-owned cooperative adopted the newly developed technologies to manufacture EMSP as an adhesives component.
PARTICIPANTS: Individuals (Principle Investigators): Lawrence A. Johnson, Project Director, Professor, Food Science & Human Nutrition, responsible for identifying mechanical and thermal processes that improve the extraction of oil and protein; Deland Myers, Professor, Food Science & Human Nutrition, responsible for optimizing enzyme hydrolysis of soy protein for use as an industrial adhesive in wood products, and working with West Central Cooperative to commercialize the technology; Charles E. Glatz, Professor, Chemical and Biological Engineering, responsible for work on understanding why yield improvement(s) are observed; Stephanie Jung, Assistant Professor, Food Science & Human Nutrition, responsible for selecting appropriate mechanical, thermal and physical strategies to de-emulsify the protein-oil emulsions; Patricia Murphy, Professor, Food Science & Human Nutrition, responsible for optimizing the sequential cell dismantling process; Timothy Stahly, Professor, Animal Sciences,
responsible for evaluating strategies to produce high-protein feed materials with greater biological value as a source of digestible nutrients and health enhancing molecules for monogastric animals. Collaborators and Contacts: Chris Penet, Genencor International; Peter Birschbach, Genencor International. Training and Professional Development: Buddhi Lamsal, Post-Doctorate Research Associate, Food Science & Human Nutrition; Juliana Nobrega, Post-Doctorate Research Associate, Food Science & Human Nutrition; Richard Faris, Technician, Animal Science; Kerry Campbell, Graduate Research Assistant, Chemical and Biological Engineering; Ramon Morales-Charbrand, Graduate Research Assistant, Chemical and Biological Engineering; Virginie Kapchie, Post-Doctorate Research Associate, Food Science & Human Nutrition.
TARGET AUDIENCES: The soybean processing industry, such as the National Oilseed Processing Association. Soybean commodity boards, such as the United Soybean Board, the American Soybean Association, and the Iowa Soybean Promotion Board.
PROJECT MODIFICATIONS: We did not scale-up the enzyme-assisted aqueous extraction process to large-scale pilot-plant trials as planned because significant advances were still being made to the process as carried out in the laboratory and we judged it to be premature for such trials.
Impacts
Water-based enzyme-assisted aqueous extraction processing (EAEP) of soybeans offers alternatives to traditional hexane extraction to produce oil for food and biofuel production. Hexane is a regulated pollutant and compliance with new emission standards are becoming increasingly difficult and expensive. Hexane is also highly flammable and safety is a major issue due to frequent fires and explosions in processing plants. EAEP may also enable new opportunities to add value to oil and meal products and may also provide a basis for establishing biorefining technologies for soybeans to convert soybeans into biofuels and value-added biobased products. EAEP may be less costly and require less capital investment than conventional oil extraction with hexane and may be suitable for localized small-scale operations that integrate extremely well into biodiesel production and/or identity-preserved processing of specialty soybeans with value-added traits for end-users. Understanding
of oil stability/de-emulsification phenomenon will help not only EAEP soybean processing, but other oil processes that are faced with similar problem emulsion problems. The results of this project should lead to improved performance properties in food, feed and adhesive applications as well as improved extraction efficiency in processing soybeans into value-added protein ingredients. We discovered how to achieve over 90% oil extraction from soybeans using water-based EAEP and how to break the highly stable cream emulsion to recover all of the oil in the cream as free oil using enzymes. We have perfected a new soy protein co-product that can be used in wood adhesives that is ready for transfer to the soybean industry and adoption by the wood products industry. The wood products industry are looking for technologies that reduce costs, replace traditional petroleum-derived materials, and provide less formaldehyde exposure (potentially cancer promoting) to workers. These advances will
lead to new, lower cost soybean products and allow food processors to produce soybean ingredients that have not been exposed to organic solvents about which consumers are becoming increasingly concerned.
Publications
- Jung, S., Lamsal, B.P., Stepien, V., Johnson, L.A. and Murphy, P.A. 2006. Functionality of soy proteins produced by enzyme-assisted extraction. J. Am. Oil Chem. Soc. 83(1):71-78.
- Lamsal, B.P., Reitmeier, C., Murphy, P.A., and Johnson, L.A. 2006. Enzymatic hydrolysis of extruded-expelled soy protein and resulting functional properties. J. Am. Oil Chem. Soc. 83(8):732-737.
- Lamsal, B.P., Murphy, P.A., and Johnson, L.A. 2006. Flaking and extrusion as a mechanical treatment for enzyme-assisted aqueous extraction of oil from soybeans. J. Am. Oil Chem. Soc. 83(11):973-979.
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Progress 09/01/05 to 09/01/06
Outputs
This year's work focused on improving soy-protein-based wood adhesives and aqueous extraction processing (AEP) to recover oil from soybeans. We improved the protein hydrolysates from soy flour by using a combination of proteases and carbohydrases. The new hydrolysate can replace up to 20% of the petroleum-based chemicals in phenol-formaldehyde (PF) adhesive formulations. The enzyme process reduces the cost of preparing the hydrolysate. Hydrolysates made with protease, carbohydrase, and a combination of the two enzymes had different bond strengths and water resistances, particularly at higher replacement levels. Protein hydrolysates allow manufacturers to make a variety of hydrolysates for different adhesives unlike the conventional chemical process that produces only one hydrolysate for a given viscosity. We continue to identify mechanical and thermal processes that improve oil extraction during AEP. We attempted to fix protein bodies by heating the beans prior to AEP
to prevent emulsion formation and enhance enzymatic release of oil. When soybeans and full-fat flour were heated at 97 degrees C for 10 min before AEP, both protein and oil yields decreased. When using the sequential cell dismantling process, oil bodies were isolated by sucrose floatation centrifugation from hydrated soybean cotyledons by homogenization of cotyledons and enzyme-assisted methods. The benchmark method yielded oil bodies accounting for 45% of the bean lipid. The enzyme-assisted methods involved grinding, enzyme incubation, cell lysis and centrifuging. Dry grinding dry cotyledons and wet grinding hydrated cotyledons were tested. A coffee grinder and Magic mill were used for dry seeds, while a blender and a Polytron were evaluated for hydrated material. Cellulases and pectinase were used to weaken cell walls. No oil bodies could be isolated without enzyme treatment. Both single enzyme and enzyme cocktails were evaluated. Cell lysis to break cell walls was evaluated with
blender grinding and ultrasonication. Particle size was important to enzyme-assisted cell wall degradation. The highest oil body yield was 47%, using a Magic mill for grinding and a blender for cell lysis when incubating with 1% pectinase. The cream resulting from AEP was oil associated with significant amounts of large proteins and some lecithin. Enzyme-assisted demulsification using 1% protease converted 35% of the emulsified to free oil. The cream obtained from extrusion- and enzyme-assisted AEP (EEAEP) could be destabilized with total free oil release by using either 2.5 percent Fungal Protease Concentrate (FPC) or LysoMax. FPC is more efficient than LysoMax. We filed a provisional patent on enzymatic strategies to de-emulsify the cream. Membrane de-emulsification was ineffective for protease-treated creams. Protein fractions obtained by acid precipitation of skim milk obtained with AEP, extrusion-AEP, EEAEP and enzyme-AEP contained 70 to 89 percent protein. Viscosities of these
proteins were affected by processing; the more noticeable change was observed for the EEAEP protein fraction which increased by a factor of 9 compared to the AEP protein fraction.
Impacts
Aqueous Extraction Processing (AEP) is an alternative to hexane in oilseeds extraction to recover vegetable oils. Hexane is a regulated pollutant and costs of compliance with emission standards are becoming increasingly difficult and expensive. Hexane is also highly flammable and frequent fires and explosions cause considerable property damage and occasional loss of life and personal injury. AEP solves these problems and may enable new opportunities to add value to oil and meal products. AEP may require less capital investment than conventional oil extraction with hexane and be suitable for localized small-scale operations that enable identity-preserved processing. Understanding the oil stability/de-emulsification phenomenon will help not only AEP, but other oil processes that are faced with the same problem. We also developed a new enzyme process to make hydrolyzed soy protein that is very useful in replacing phenol formaldehyde in wood adhesives and integrates into
AEP. Reducing worker exposure to formaldehyde is important to reducing health risks to workers in wood materials manufacturing industries. Using soybean meal in adhesives may also reduce adhesive costs as the prices of phenol formaldehyde are tied to petroleum prices. Our cell dismantling process may enable totally new approaches to using water to recover oil from oilseeds. This project should lead to improved performance properties in food, feed and adhesive applications as well as improved extraction efficiency in processing soybeans into value-added oil and protein ingredients.
Publications
- Lamsal, B.P., Reitmeier, C., Murphy, P.A. and Johnson, L.A. 2006. Enzymatic hydrolysis of extruded-expelled soy protein and resulting functional properties. J. Am. Oil Chem. Soc. 83(8):732-737.
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