Progress 05/12/99 to 05/11/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Corn wet milling is a technology that separates the corn kernel into starch, corn germ, corn gluten meal (a 60% protein feed product) and corn gluten feed (a 21% protein feed product). The corn germ is processed for oil--generally in a separate facility. Wet milling is energy and capital intensive. The process also uses sulfur dioxide, which is an environmental concern. The goal of this project is to develop new or modified ways to process corn to add value to the products, improve processing efficiencies, and reduce environmental problems. Agricultural Research Service (ARS) scientists' main approach to furthering our understanding of corn wet milling is to better understand how the structure and composition of the corn kernel influences the milling process. ARS is also developing new processes and
modifications to old processes to better separate kernel components. This information will be used to develop technologies that are optimal for component separation and require less energy, capital, and sulfur dioxide. The research associated with this project falls under National Program 306 - Quality and Utilization of Agricultural Products [New Processes, New Uses, and Value-Added Foods and Biobased Products]. The mission of this program is to enhance the economic viability and competitiveness of U.S. agriculture by maintaining the quality of harvested agricultural commodities or otherwise enhancing their marketability, developing environmentally friendly and efficient processes, and expanding domestic and global market opportunities through the development of value-added food and nonfood products. The program has two specific aims: (1) quality characterization, preservation, and enhancement of agricultural commodities and products and (2) the development of new processes, new
uses, and value-added foods and biobased products. 2. List the milestones (indicators of progress) from your Project Plan. There are four principal objectives associated with this project. These are to identify corn proteins that influence milling properties, to separate components of corn gluten into value-added products, to identify processing factors that affect corn oil quality, and to find alternatives to sulfur dioxide for corn wet-mill steeping. In past years, we have worked to understand how the corn endosperm protein structure is affected during corn steeping, which is conducted in the presence of sulfur dioxide and lactic acid. Sulfur dioxide is known to promote the solubilization of protein by breaking protein bonds. In our work, lactic acid was also found to solubilize specific proteins during steeping and it's likely that this additional protein dissolution contributes to the improved starch yields observed when lactic acid is present during steeping. Attempts were
also made to correlate milling characteristics with various kernel protein fractions, and the best correlations were obtained with the glutelin class of proteins. In support of this work, improved laboratory-scale milling methods were also developed. Current work involves the separation of yellow pigments (carotenoids) from corn gluten meal. Removal of the pigments should allow the meal to be used in additional feeding markets. The pigmented extracts are also expected to be valuable to the poultry industry, as the yellow color contributes to egg yolk and chicken skin color. 3. Milestones: A. For the last 18 to 24 months, the main goal has been to learn how to extract pigments from corn gluten meal. We were successful at removing the pigments by extraction with alcohols. Ethanol was found to be the best solvent, given the experience that the corn industry has with this chemical. Other alcohols, however, can also be used. A light colored meal is produced by this process that is
comparable in pigmentation to soybean meal. The extracted pigments are very unstable and degrade rapidly, especially when exposed to light, oxygen, and temperature. The stability of the extracts is best maintained by storage at low temperatures (-20 C and lower), which is expensive. Drying the pigments down onto starch- or protein-based solid substrates reduces, but did not eliminate, the degradation. Approximately, 70% of the pigments can be maintained over a six-week period by this approach. B. The project is scheduled for termination on 5/11/04. Nevertheless, the next step in this development work would be to develop a scaled-up process to produce sufficient material for animal feeding trials. Additional work on the stabilization of the alcoholic extracts would also be useful. 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment during FY 2004. Some additional extraction experiments were conducted on corn gluten meal, and
the stability of the pigments extracted was studied under different storage conditions. Light exposure caused rapid degradation. Reducing storage temperature helped maintain the pigments, but complete stability was only achieved at temperatures below -20 C. Antioxidants were not effective at reducing the rate of degradation. Drying the pigments onto starch and protein-based substrates offered some protection with 70% of the pigments remaining after a 6 week storage period. B. Other Significant Accomplishment(s), if any. None. C. Significant Activities that Support Special Target Populations. None. D. Progress Report opportunity to submit additional programming information. This project is scheduled to be eliminated at the completion of the OSQR review process. Personnel and funds will be moved to an oilseed processing project, CRIS 6435-41000-082-00D, entitled "New and Expanded Uses of Oilseed Products and By-Products." 5. Describe the major accomplishments over the life of the
project, including their predicted or actual impact. This research project was last updated during 1999 and is due to expire this year. Under the project, ARS scientists found that approximately half of the starch lost to corn fiber in the basic wet-milling process was recoverable by a modified processing of the fiber. Recovery of this additional starch would increase starch yields by 1-1.5%. A number of processors have developed or are developing methods to achieve this recovery. Pilot-plant methods were developed to separate the lipid fraction from corn fiber. This oil fraction contains compounds known to lower blood cholesterol levels. Methods were developed to extract the carotenoid pigments from corn gluten meal, resulting in a bland-colored meal and a pigmented extract, both of which may be commercially valuable. Two corn processing companies have expressed interest in this research area. Improved methods were developed to mill corn on a laboratory scale. The techniques
improve the precision of the process, making it possible to see the influence of smaller effects on milling yields, and should be useful to future researchers in the field. Finally, lactic acid was found to solubilize significant amounts of additional protein during corn steeping and this appears to be related to increased starch yields achieved in the presence of this acid during industrial milling. At present, an understanding of exactly how this influences the milling process is lacking. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Publication and presentations have been made on all of the completed work. Industrial processors have been working on the milling process to increase starch yields and we've been told that milling strategies similar
to those described in these publications have been incorporated to reduce starch losses to fiber. The laboratory milling work will be utilized by scientists in the field to further understand the wet-milling process. One company is looking into the carotenoid extraction work with the goal of producing a white-corn-like line treated corn dough for tortilla production product that would add considerable value to yellow corn in some foreign markets.
Impacts
(N/A)
Publications
- Dowd, M.K., Pelitire, S.M. 2004. Extraction, recovery, and stability of carotenoids from corn gluten meal. Meeting Abstract.
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Corn wet milling is a technology that separates the corn kernel into starch, corn germ, corn gluten meal (a 60% protein feed product) and corn gluten feed (a 21% protein feed product). The corn germ is processed for oil--generally in a separate facility. Wet milling is energy and capital intensive and uses sulfur dioxide, which is an environmental concern. The goal of this project is to develop new or modified ways to process corn to add value to the products, improve processing efficiencies, and reduce environmental problems. Agricultural Research Service (ARS) scientists' main approach is to better understand how the structure and composition of the corn kernel influences the milling process. New processes are being developed to separate the kernel components to increase product value. This information will be used to develop processes that are optimal for component separation and
require less energy, capital, and sulfur dioxide. 2. How serious is the problem? Why does it matter? Unrecovered starch exits the wet-milling process in the corn gluten feed fraction. This material is sold mainly in Europe for a price significantly less than the price of unprocessed corn. It has been estimated that for a medium size plant (200,000 bushels/d) each 1% increase in starch yield increases plant revenue by approximately $3 million. The sulfur dioxide used in the process is released into the air and water. Sulfur usage in wet-milling facilities is tightly controlled, and significant starch losses occur because of these environmental controls. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? The research program is aimed at improving the processing of corn. This work is a component of National Program 306: Quality and Utilization of Agricultural Products [New Processes, New Uses, and Value-Added Foods and
Biobased Products] (100%). 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment during FY 2002. To provide additional markets for corn protein products, ARS scientists have undertaken a series of experiment to study the separation of different corn components. Pigmented compounds (carotenoids) were extracted from gluten meal, and the stability of the extracts was studied under different storage conditions. The effects studied included temperature, light exposure, the presence of antioxidants, and the influence of drying the pigments onto starch and protein-based substrates. Reduced temperature was most effective for maintaining the stability of the extracted pigments, although drying the pigments onto starch or protein-based substrates offered some protection. B. Other Significant Accomplishment(s), if any. Sampling methods were developed to reduce the computational time needed to study the conformational features of novel
corn-based polymers. Statistical conformational searching routines were implemented and used to study the structural features of glucose-based synthetic polymers that are easily produced from starch. The type of sugars that make up the polymer backbone, chemical modification of the sugars, and dielectric constant (i.e., environmental effects) were studied. The results may help predict polymer properties and suggest chemistry that might yield additional polymers having useful properties. C. Significant Accomplishments/Activities that Support Special Target Populations. None. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. This research project was updated during 1999. Under the prior research project, ARS scientists found that approximately half of the starch lost to corn fiber in the basic process was recoverable by a modified processing of the fiber. Recovery of this additional starch would increase wet mill starch
yields by 1-1.5%. A number of processors have developed or are developing methods for achieving this recovery. In addition, pilot-plant methods were also developed to separate the lipid fraction from corn fiber. This fraction contains compounds known to lower blood cholesterol levels. Methods have been developed to extract the carotenoid pigments from corn gluten meal, resulting in a bland- colored meal and a pigmented extract, both of which may be commercially valuable. Finally, lactic acid was found to help solubilize protein during corn steeping and this appears to be related to increased starch yields achieved in the presence of this acid. An understanding of how this occurs is, at present, lacking. 6. What do you expect to accomplish, year by year, over the next 3 years? FY 2004 - This project will terminate in May of 2004 and the personnel and funding will be shifted to CRIS project 41000-082-00D. Between now and May 2004 a number of unfinished efforts will be completed.
The extraction of corn pigments from corn gluten meal will be completed and data on the extraction of corn proteins because of the presence of lactic acid and sulfur dioxide during corn steeping conditions will be analyzed. Manuscripts on both of these topic will be prepared. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Corn refiners have donated corn gluten samples to support the carotenoid pigment extraction project. Developed milling techniques have been used by seed companies to test for seed milling properties.
Impacts
(N/A)
Publications
- Dowd, M.K. Improvements to Laboratory-Scale Maize Milling Procedures. Industrial Crops and Products, 2003. v. 18. p. 67-76.
- Dailey, O.D., Jr. Role of lactic acid in corn wet-mill steeping: a study of structure-activity relationships. 225th American Chemical Society National Meeting, Division of Agricultural and Food Chemistry. 2003. Abstract No. AGFD00064.
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Progress 10/01/01 to 09/30/02
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Corn wet milling is a technology that separates the corn kernel into starch, corn germ, corn gluten meal (a 60% protein feed product) and corn gluten feed (a 21% protein feed product). The corn germ is processed for oil--generally in a separate facility. The wet-milling process is energy and capital intensive and uses sulfur dioxide, an oxygenated sulfur compound, which is an environmental concern. The goal of this project is to develop new or modified ways of processing corn to add value to the products, improve processing efficiencies, and reduce environmental problems. Agricultural Research Service (ARS) scientists' main approach is to try to better understand how the structure and composition of the corn kernel influences the milling process. We are also developing new processes to separate the kernel components to increase product value. We intend to use this information to develop
processes that are optimal for component separation and require less energy, capital, and sulfur dioxide. 2. How serious is the problem? Why does it matter? Unrecovered starch exits the wet-milling process in the corn gluten feed fraction. This material is sold mainly to the European feed market for a price significantly less than the price of unprocessed corn. It has been estimated that for a medium size plant (200,000 bushels/d) each 1% increase in starch yield increases revenue by approximately $3 million. The sulfur dioxide used in the process is released into the air and water. Currently, sulfur release by wet-milling facilities is very tightly controlled. Significant starch losses occur because of these environmental controls. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? The research program is aimed at improving the processing of corn. This work is a component of National Program 306: Quality and
Utilization of Agricultural Products [New Processes, New Uses, and Value-Added Biobased Products] (100%). 4. What was your most significant accomplishment this past year? A. Single Most Significant Accomplishment during FY 2002. To provide additional markets for corn protein products, orange-yellow pigments, known as carotenoids, were extracted from corn gluten meal to yield an uncolored high-protein meal and a pigmented extract that should be valuable to the feed industries. The effects of solvent type, contact time, meal-to-solvent ratio, moisture level, and heat exposure on the extraction of corn gluten meal pigments was studied. Carotenoid recovery was best achieved with ethanol or methanol on meals not exposed to heat. The extraction of pigments from corn gluten meal may result in additional corn meal and ingredient products that are valuable to aquaculture and poultry industries. B. Other Significant Accomplishment(s), if any. (1) To better understand the functionality of
enzymes that are used to break down hemicelluloses (a polysacchoride used in plants in conjunction with allulose and lignin) into fermentable sugars, the preferred ring conformations of xylose and arabinose (the sugars that make up the polysacchoride skeleton of hemicellulose) were determined. At the request of enzymologists, computational chemistry models were used to understand the conformations of these hemicellulosic sugars. Xylose was found to have potentially important non-chair conformations that may help explain proposed xylanase hydrolysis mechanisms. The results may be valuable to enzymologists working to improve the digestibility of hemicellulosic materials. C. Significant Accomplishments/Activities that Support Special Target Populations. None 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact? This research project was updated during 1999. Under the prior research project, ARS scientists found that
approximately half of the starch lost to corn fiber in the basic process was recoverable by a modified processing of the fiber. Recovery of this additional starch would increase wet mill starch yields by 1-1.5%. A number of processors have developed or are developing methods for achieving this recovery. In addition, pilot-plant methods were also developed to separate the lipid fraction from corn fiber. This fraction contains compounds known to lower serum cholesterol. Finally, lactic acid was found to help solubilize protein during corn steeping and we believe this is related to increased starch yields achieved in the presence of this acid. An understanding of how this occurs is, at present, lacking. 6. What do you expect to accomplish, year by year, over the next 3 years? FY 2003 - During the upcoming year, we will continue to study the extraction of carotenoid pigments from corn gluten meal. Experiments to be conducted include further studies on the influence of the
solvent-to- meal ratio (to reduce the co-extraction of protein) and the influence of multiple extractions (to further reduce pigmentation of the meal). Because carotenoids are prone to oxidation, a series of tests will be conducted to determine the best storage conditions for the extracts. FY 2004 - The extraction of corn proteins and the importance of the removal of these proteins on the wet-mill process will be studied. Experiments will be conducted on the effect of protein enzymes on the dissolution of the corn endosperm protein matrix during corn steeping. From this information, we hope to determine which endosperm (seed storage tissue) proteins are responsible for holding starch granules within the matrix. FY 2005 - The influence of kernel maturity on starch properties will be studied. The pollination of corn ears will be controlled and the ears will be harvested as the starch and protein components accumulate. Starch will be recovered by wet milling and the properties of the
various starch fractions tested for property differences 7. What technologies have been transferred and to whom? When is the technology likely to become available to the end user (industry, farmer other scientist)? What are the constraints, if known, to the adoption durability of the technology? Corn refiners have donated corn gluten samples to support the carotenoid pigment extraction project. 8. List your most important publications and presentations, and articles written about your work (NOTE: this does not replace your review publications which are listed below) Hron, Sr., R.J., Dowd, M.K. Oilseed and Grain Processing at the Southern Regional Research Center. The Cotton Gin and Oil Mill Press, 2001. 102(18) . p. 10-11.
Impacts
(N/A)
Publications
- 1. Dailey, Jr., O.D. Effect of lactic acid on protein solubilization and starch yield in corn wet-mill steeping: A study of hybrid effects. Cereal Chemistry. 2002. v. 79(2). p. 257-260.
- 2. Dowd, M.K., Rockey, W.M., French, A.D., Reilly, P.J. MM3 Modeling of Aldopentose Pyranose Rings. Journal of Carbohydrate Chemistry. 2002. v. 21(1&2). p. 11-25.
- 3. Dailey, Jr., O.D. Effect of steeping chemicals on kernel hydration during laboratory steeping of yellow dent corn hybrids. Corn Utilization and Technology Conference. 2002. Abstract p. 161.
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Progress 10/01/00 to 09/30/01
Outputs
1. What major problem or issue is being resolved and how are you resolving it?
Corn wet milling is a technology that separates the corn kernel into starch, corn germ, corn gluten meal (a 60% protein feed product) and corn gluten feed (a 21% protein feed product). The corn germ is processed for oil--generally in a separate facility. The wet-milling process is energy and capital intensive and uses sulfur dioxide, which is an environment concern. The goal of this project is to develop new or modified ways of processing corn to add value to the products, improve processing efficiencies, and reduce environmental problems. Agricultural Research Service (ARS) scientists main approach is to try to better understand how the structure and composition of the corn kernel influences the milling process. We are also developing new processes to separate the kernel components to increase product value. We intend to use this information to develop processes that are optimal for component separation and require less energy, capital, and sulfur dioxide.
2. How serious is the problem? Why does it matter?
Unrecovered starch exits the wet-milling process in the corn gluten feed fraction. This material is sold mainly to the European feed market for a price significantly less than the price of unprocessed corn. It has been estimated that for a medium size plant (200,000 bushels/d) each 1% increase in starch yield increases revenue by approximately $3 million. The sulfur dioxide used in the process is released into the air and water. Currently, sulfur release by wet-milling facilities is very tightly controlled. Significant starch losses occur because of these environmental controls.
3. How does it relate to the National Program(s) and National Component(s)?
The research program is aimed at improving the processing of corn. This work is a component of National Program 306: Quality and Utilization of Agricultural Products [New Processes, New Uses, and Value-Added Biobased Products] (100%).
4. What were the most significant accomplishments this past year?
A. Single Most Significant Accomplishment during FY 2001. To better understand the chemical changes that occur during wet-mill steeping of corn, protein extraction studies were conducted on isolated corn seed storage material (endosperm). The endosperm was contacted with different steeping solutions, i.e. combinations of lactic acid and sulfur dioxide, and dissolution of the endosperm protein matrix was studied. Two proteins were identified as being solubilized when the steepwater contained both chemicals as it does in industrial practice. The identification of these proteins may be useful for the development of hybrids with improved milling properties. B. Other Significant Accomplishment(s), if any. (1) Corn composition is affected by the pollination method used to produce the corn and laboratory wet-milling procedures are being used for hybrid selection, but it is not clear if pollination method directly influences milling results. Compositional, physical, and wet-milling
properties of open- and self-pollinated corn hybrids were determined for five different hybrids. Pollination method did influence starch and gluten protein recovery of these corn hybrids. Consequently, pollination method must be accounted for when comparing laboratory wet milling results among corn hybrids. (2) Laboratory wet milling procedures are used to simplify the screening of hybrids, the influence of steeping conditions, etc. on corn milling properties, but these procedures are highly variable. A modified 100-g corn wet-milling procedure was developed to optimize starch recovery and several hybrids were steeped in solutions containing different concentration of lactic acid ranging from 0.00 to 1.00%. Starch recoveries and protein solubilization during steeping were highly correlated and were enhanced in solutions containing LA, with peaks being reached for solutions containing either 0.30% or 0.50% LA. C. Significant Accomplishments/Activities that Support Special Target
Populations. None.
5. Describe the major accomplishments over the life of the project including their predicted or actual impact.
This research project was updated during 1999. Under the prior research project, ARS scientists found that approximately half of the starch lost to corn fiber in the basic process was recoverable by a modified processing of the fiber. Recovery of this additional starch would increase wet mill starch yields by 1-1.5%. A number of processors have developed or are developing methods for achieving this recovery. In addition, pilot-plant methods were also developed to separate the lipid fraction from corn fiber. This fraction contains compounds known to lower serum cholesterol. Finally, lactic acid was found to help solubilize protein during corn steeping and we believe this is related to increased starch yields achieved in the presence of this acid. An understanding of how this occurs is, at present, lacking.
6. What do you expect to accomplish, year by year, over the next 3 years?
FY 2002 - During the upcoming year, we will continue to study how endosperm structure influences starch recovery during wet milling. Proteins found to be solubilized by steeping conditions will be characterized. Because some corn storage proteins have already been isolated and characterized, we will compare the properties of our target proteins with these data, which might reduce the work. FY 2003 - We will develop methods to extract the carotenoid pigments from corn gluten meal and to yield a de-colored protein product that might have added value for the aquaculture industry. We expect that the pigmented extract can be stability and will have value to the poultry industry. FY 2004 - We will begin to study the effect of processing factors (chemical exposure, heat) on corn oil quality. Because of the structure of the corn processing industry, little information is available on the influence of the chemical and heat used in the wet-milling process on the ease of processing corn germ
for oil or on the final oil quality.
7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints if known, to the adoption & durability of the technology product?
Seed companies have been directly involved in the work on how kernel properties affect wet milling and are supplying seed for this project.
8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below)
"Fats and oils research at Southern Regional Research Center (SRRC)" (an overview of lipid related research at SRRC) INFORM. 2001. v. 12. p. 537- 542.
Impacts
(N/A)
Publications
- Dailey, O.D., Jr., Dowd, M.K. Effect of Lactic Acid Concentration on Protein Solubilization and Starch Recovery in Corn Wet-Mill Steeping. American Chemical Society. 2001. Abstract p. 67.
- Dailey, O.D., Jr. Variability in Water Absorption of Germ and Endosperm During Laboratory Corn Steeping of a Yellow Corn Hybrid. Cereal Chemistry. 2000. v. 77(6). p. 721-723.
- Dowd, M.K., Dailey, O.D., Jr. Effect of lactic acid on the protein structure of corn endosperm. American Oil Chemists Society. 2001. Abstract p. S111.
- Dailey, O.D., Jr., Dowd, M.K., Brown, T.W. Role of Lactic Acid in Corn Wet-Mill Steeping: A Study of the Relationship between Protein Solubilization and Starch Yield in Ten Hybrids. American Chemical Society. 2000. Abstract 412. p. 232.
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Progress 10/01/99 to 09/30/00
Outputs
1. What major problem or issue is being resolved and how are you resolving it?
Corn wet milling is a technology that separates the corn kernel into starch, corn germ, corn gluten meal (a 60% protein feed product) and corn gluten feed (a 21% protein feed product). The corn germ is processed for oil--generally in a separate facility. The wet-milling process is energy and capital intensive and uses sulfur dioxide, which is an environment concern. The goal of this project is to develop new or modified ways of processing corn to add value to the products, improve processing efficiencies, and reduce environmental problems. Our main approach is to try to better understand how the structure and composition of the corn kernel influences the milling process. We are also developing new processes to separate the kernel components to increase product value. We intend to use this information to develop processes that are optimal for component separation and require less energy, capital, and sulfur dioxide.
2. How serious is the problem? Why does it matter?
Unrecovered starch leaves the wet-milling process in the corn gluten feed fraction. This material is sold mainly to the European feed market for a price significantly less than the price of unprocessed corn. It has been estimated that for a medium size plant each 1% increase in starch yield increases revenue by approximately $3 million. The sulfur dioxide used in the process is released into the air and water effluent. Currently, sulfur release by wet-milling facilities is very tightly controlled. Significant starch losses occur because of these environmental controls.
3. How does it relate to the National Program(s) and National Component(s)?
The research program is aimed at improving the processing of corn. This work is a component of National Program 306: New Uses, Quality, and Marketability of Plant and Animal Products - Grains, Oilseeds, and New Crops.
4. What were the most significant accomplishments this past year?
A. Single Most Significant Accomplishment during FY 2000 year: To evaluate the factors affecting the millability of various corn hybrids, it was necessary to develop a laboratory scale corn wet-milling process. Scientists at the Southern Regional Research Center (SRRC) designed, built and tested two laboratory corn wet-milling processes during the year. The processes will be used for experiments to study the influence of the corn proteins on milling properties and to study the role of lactic acid in the steeping phase of wet milling. B. Other Significant Accomplishment(s), if any: None at this time. C. Significant Accomplishments/Activities that Support Special Target Populations: There are no significant accomplishments/activities that support special target populations at this time.
5. Describe the major accomplishments over the life of the project including their predicted or actual impact.
This in house project was updated during 1999. Under the prior in house project, we found that approximately half of the starch lost to corn fiber in the basic process was recoverable by a modified processing of the fiber. Recovery of this additional starch would increase wet mill starch yields by 1-1.5%. A number of processors have developed or are developing methods for achieving this recovery. In addition, pilot-plant methods were also developed to separate the lipid fraction from corn fiber. This fraction contains compounds known to lower serum cholesterol. Finally, lactic acid was found to help solubilize protein during corn steeping and we believe this is related to increased starch yields achieved in the presence of this acid. An understanding of how this occurs is, at present, lacking.
6. What do you expect to accomplish, year by year, over the next 3 years?
FY 2001: During the upcoming year, we will continue to study how kernel properties and composition influence milling. Specifically we will try to determine what kernel properties or components lead to difficult milling situations. The initial experiment of this series is to identify the type of kernel proteins that strongly influence starch recovery and protein contamination of starch. Our initial experiment on this topic will be completed during the year. In addition, a second set of corn hybrids is currently being grown for the next phase of this work, which will attempt to better define the compositional traits that lead to milling problems. Some work will also be conducted toward understanding the effects of lactic acid on milling. FY 2002: If proteins are identified that contribute to milling problems, we will begin to characterize these proteins and use this information to start developing tools that can be used to identify these problem components prior to milling. We
anticipate that this will lead to a more optimal use of sulfur in the wet-milling process. We will also begin to study the feasibility of extracting the yellow pigments from corn protein fractions. The production of a colorless corn protein feed ingredient should be of increased value to the aquaculture industry, where a light flesh color is considered advantageous. The extracted residue should also have value to the poultry producers. We will also continue to try to increase our understanding of the chemical events that occur during corn steeping with the ultimate goal being to reduce steep time and lower the costs of this processing bottleneck. FY 2003: We will begin to study the effect of processing factors (chemical exposure, heat) on corn oil quality. Because of the structure of the corn processing industry, little information is available on the influence of the chemical and heat used in the wet-milling process on the ease of processing corn germ for oil or on the final oil
quality.
7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints if known, to the adoption & durability of the technology product?
Seed companies have been directly involved in the work on how kernel properties affect wet milling and are supplying seed for this project.
8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below)
Impacts
(N/A)
Publications
- Laederach, A., Dowd, M.K., Coutinho, P.M., Reilly, P.J. Automated docking of maltose, 2-deoxymaltose, and maltotetraose into the soybean beta-amylase active site. PROTEINS: Structure, Function, and Genetics. 1999. v. 37. p. 166-175.
- Dailey, O.D., Jr., Dowd, M.K., Mayorga, J.C. Influence of lactic acid on the solubilization of protein during corn steeping. Journal of Agricultural Food Chemistry. 2000. v. 48. p. 1352-1357.
- Dailey, O.D., Jr., Dowd, M.K., Mayorga, J.C. Role of lactic acid in corn wet-mill steeping: The relationship between protein and solubilization and strach yield. American Chemical Society Book of Abstracts. 1999. v. #1. Abstr. #AGFD067.
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