Progress 07/21/01 to 06/03/04
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? Milk is comprised of casein and whey proteins. The caseins in milk are in the form of a calcium-phosphate complex. Commercially, the casein proteins are isolated from milk for use as ingredients to improve the functional and nutritional properties of foods or to make cheese. Whey, a watery byproduct of the cheesemaking process that contains the whey proteins, is often concentrated by further processing and used to improve the functionality of foods and as a nutritional supplement. Not all whey proteins are utilized by the dairy industry; they may be used as animal feed or discarded. To increase markets for the milk proteins, as well as improve the methods used to obtain proteins from agricultural commodities, new, innovative and cost-effective technologies need to be developed. The approach used
will:create new processes for casein and whey protein manufacture that are competitive;ensure that the processes are environmentally sound; and ensure that the technology is sufficiently open-ended so that it can be used to isolate proteins from other agricultural commodities such as corn and soy. New technologies are required for processing of proteins because current technology leaves protein-containing waste streams that require additional treatment before further use or disposal. Treatment adds salts to the waste streams. This makes it difficult to economically recover the proteins and ensure their consistency from batch to batch. Improvements in their quality will increase demand for them in food and non-food products. New processing technologies will also allow the introduction of new protein products, in addition to milk protein products, such as corn protein concentrates and isolates, to the market. These products are not currently available for food use, because of the
harsh processing methods used in wet and dry-milling operations. This research primarily supports National Program 306, "Quality and Utilization of Agricultural Products" and Departmental Goal 1, "Enhance Economic Opportunities for Agricultural Producers", Objective 1.1: Provide the Science-Based Knowledge and Technologies to Generate New or Improved High Quality, Value-Added Products and Processes to Expand Domestic and Foreign Markets for Agricultural Commodities. 2. List the milestones (indicators of progress) from your Project Plan. This project has been terminated and will be replaced by project 1935- 41000-063, which has completed the OSQR National Program 306 review process and was certified on June 15, 2004. The project will terminate on September 30, 2008. In FY 2004, modify the drying system and develop feed and collection systems for design of a continuous drying process for films made from casein and other agricultural proteins or materials. Optimize the process. Adapt the
continuous drying process to casein produced by high pressure carbon dioxide. Examine the drying phase of the film making process. Collect kinetic data for whey protein fractionation scale up studies. Make preliminary runs for carbon dioxide protein studies. In FY 2005, optimize the process for casein produced by high pressure carbon dioxide and for other commercially available dairy fractions. Make pilot scale samples to foster technology transfer. Perform a cost estimate for the process. Electron microscopy studies completed on the films. Determine the factors responsible for the film making process in continuous systems. Build pilot scale process to isolate enriched fractions of the whey proteins. In FY 2006, adapt the continuous film process to NFDM partially substituted for casein. Establish a CRADA to commercialize the carbon dioxide casein film process or the carbon dioxide casein coating material. 3. Milestones: 3A. Most of the milestones for FY 2004 have been met and are
listed below. The milestones listed for FY 2005 and FY 2006 were reprioritized and are found in the new project plan for 1935-41000-063. FY 2004 Modify the drying system. A pilot plant, continuous belt microwave dryer equipped with steam and electrical heat was adapted to simulate a semi- continuous drying process. The belt was porous and not suitable for drying film-forming solution. The microwave option was disconnected and heating was accomplished by electrical heat only. Develop feed and collection systems for design of a continuous process. Experiments utilizing the semi-continuous operating dryer to determine the relevant parameters for controlling feeding of the film solution were completed. These results will be used to design the feed system for continuous operation. Optimize the process. Parameters for feeding the solution onto the belt, selection of belt material, and removing the dried film from the belt were identified in experiments using calcium caseinate. Measurements
to determine the scientific basis for parameter selection and value will be identified in the new project. Measurements will include those such as surface energy of the belt and surface tension of the solution. Adapt the continuous drying process, tested on solutions of calcium caseinate, to drying solutions of casein produced by high pressure carbon dioxide. Experiments to identify the drying mechanism for casein produced by high pressure carbon dioxide have been completed and compared to that for calcium caseinate. Examine the drying phase of the film making process. Drying kinetics were established for drying of protein containing films and were published. Collect kinetic data for whey protein fractionation scale up studies. This work was not initiated this FY and is included in the new project plan. Make preliminary runs for carbon dioxide protein studies. Initiated research to examine the effects of carbon dioxide pressure on protein quality. Only one pressure examined.
Additional experiments are planned in the new project plan. 4. What were the most significant accomplishments this past year? A: Single Most Significant Accomplishment during FY 2004: Development of a continuous process for producing agricultural films. About 60 million tons of petrochemical-based films and coatings are produced annually with 32 million tons used in food packaging. The only successfully reported method for making protein-based films has been by a casting process that results in films with variable thickness and uneven properties. If the films can be made by a continuous process, they could command a significant market because they are not only readily biodegradable, but also edible. Researchers in the DPPRU developed a semi- continuous process for making milk protein based films that is applicable to other protein or carbohydrate-based films. Central to the process is the selection of belt materials that permit the film solution to properly wet the surface, dry, and
easily release. A patent was filed for the process. When this process is scaled-up to a large-scale continuous process, it will present to industry a potentially commercially feasible process for making biodegradable coatings and films from surplus dairy ingredients. B: Other Significant Accomplishments: Design of a continuous process for making films from agricultural proteins or carbohydrates requires parameters for feeding the solution to the belt, selection of belt material, and removal of the dried film from the belt. The parameters for pumping or feeding the solution are a function of the viscosity of the film solution, but selection of belt material and the ability to remove the dried film from the belt depend not only on the properties of the belt but also the properties of the specific protein solution. In initial studies, the semi-continuous process for making films was designed and then tested using calcium caseinate which is commercially available. The physical
properties of the films produced continuously were the same as those simply cast from solution. It was not known, however, if solutions of other milk proteins, such as casein produced using carbon dioxide, CO2-casein, could be processed continuously using the parameters selected for calcium caseinate. In tests, the physical and tensile properties of CO2-casein films produced using the semi-continuous process differed slightly from those produced using the casting method. This indicates that that the selection of belt may have affected the properties of the films and may be an important variable in processing agricultural materials. C: Significant Accomplishments/Activities that Support Special Target Populations: None. D. Progress Report: This report serves to document research funded by a Grant between ARS and EnerGenetics International, Inc, Nauvoo, IL. The objectives of this work were to increase pilot plant production of a protein product so that samples may be distributed to
potential users in the food and pharmaceutical industries and to characterize the properties of the product. EnerGenetics International has constructed a pilot plant to produce protein samples using the CO2 technology. Test samples have been distributed to several protein processing companies for inclusion in their products and feedback. EnerGenetics also displayed the protein products at the 2004 Institute of Food Technologists Annual Food Meeting and Food Expo, Las Vegas, Nevada. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Casein Program Much of the work in this project builds on the accomplishments of the earlier research project, 1935-41000-044 that terminated in FY 2000 and was bridged to FY 2001. The accomplishments of 1935-41000-054 and 1935- 41000-058, that are pertinent to the new project are stated in the text that follows. Carbon dioxide (CO2) was used as an agent to remove the milk protein, casein, from
milk to investigate the use of this environmentally benign solvent (CO2) as a substitute for acids that are commonly used in protein processing. In addition, the processing technology to handle CO2, which exists as a gas in nature, was developed. One of the problems solved in this study was developing new machinery so that large quantities of milk could be contacted with CO2 in a short period of time while removing the casein from the machine. This process has been licensed by a company desiring to apply the technology to corn protein. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. To show that using CO2 as an agent to remove casein from milk is no more expensive than using acids such as hydrochloric acid (HCl), economic studies were done. These studies showed that the operating costs for casein precipitated by CO2
(CO2-casein) are less than those for acid casein or calcium caseinate obtained using acids, if the CO2 is collected and used again. Equipment costs are similar for the two operations. This is a significant finding because it was previously believed that CO2 processes would be prohibitively more expensive due to equipment costs. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. In order to build new machines that use CO2 to remove proteins from agricultural commodities such as milk, knowledge of the solubility of CO2 in milk is required. Solubility values allow engineers to calculate how much CO2 to add to a given amount of milk or protein containing solution. We measured the solubility of CO2 in milk and compared these values to known values of the solubility of CO2 in water. Solubility studies showed that the solubility of
CO2 in milk was comparable to its solubility in water under most conditions, meaning that existing aqueous data may be used in design calculations. This is a significant result because data acquisition for high pressure systems represents a significant outlay in resources and researcher time. This research addresses Action Plan Component 2. New Processes, New Uses and Value- Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Casein removed from milk using CO2 (CO2-casein) has a higher calcium content than casein removed from milk using an acid such as HCl. Studies showed that when CO2 is added to milk, it behaves as an acid, but the fact that it's also a gas at high pressure seems to affect the properties of water in the immediate vicinity of the casein. Milk is about 90% water. This causes it to separate from the milk sooner than it does if HCl is used. This is significant because it shows that the
pressure component preserves the calcium content of the casein. Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Most protein films dissolve readily in water. Films were made from the CO2-casein derived from milk, and yielded a product that is barely soluble in water and is much less permeable to water than films made from the milk salt, calcium caseinate. This is significant because additional chemicals do not have to be added to decrease the film's solubility in water. The effectiveness of the CO2-casein film as a moisture barrier for food use was compared against a calcium caseinate film by dipping potatoes in either a CO2-casein solution or a calcium caseinate solution before frying them in oil. The moisture loss and oil-uptake of the potatoes were measured. Potatoes coated in the CO2-casein solution absorbed significantly less oil and
lost less water than the calcium caseinate coated potatoes. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Films made from synthetic polymers are often loaded with material for controlled release products, ranging from scents to drugs. The material in the film may be chemically attached to the polymer or held by its structure. In experiments to determine the applicability of CO2-casein films for this application, CO2-casein films, wet or dry, were added to a reactor along with a dye. Conditions were identified in which the dye penetrated the films. If the dye washed off, it obviously was not attached to the film, if it did not, it may have reacted with the casein. These experiments showed that reactions for modification of proteins might be facilitated by gas interaction, instead of by environmentally undesirable
solvents. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Chemical reactions have been carried out using CO2-casein and calcium caseinate. The purpose was to detect differences in the two caseins, which were separated from milk using either CO2 or HCl. This information will be used as the basis for modifications of proteins to be tailored for different applications. The results indicate that CO2-casein has a more organized structure than acid casein. This gives casein a lower water solubility that may make it useful in an application as a hydrogel in a controlled release formulation. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. The feasibility of using
commercial acid casein or CO2-casein developed using our high-pressure technology as replacements for the synthetic polymers that are used commercially in controlled release products was tested. Controlled release products slowly release drugs or ingredients from a film, patch or gel. In our experiments, gels of either casein and gelatin containing the drug, theophylline, were made and the release of theophylline was measured. The studies showed that the release of the drug from the casein/gelatin gel was comparable to that of release from materials made from synthetic polymers. This initial study demonstrates that casein/gel structures have the potential of replacing synthetic materials in release applications, not only in the drug industry, but in food formulations, room fresheners, and other applications where timed release is required, such as in pesticide release. This research addresses Action Plan Component Action Plan Component 2. New Processes, New Uses and Value-Added
Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Plastic wraps are used on foods to extend their shelf-life by preventing moisture loss and by protecting them from oxidation. Protein films, which have been proposed as replacements for plastic wraps, are good oxygen barriers but dissolve readily in water, which limits their use as moisture barriers. In our studies, films prepared from carbon dioxide- casein, a form of the casein developed in our laboratory, were found to be barely soluble in water; have good moisture barrier properties compared to films made from other protein films; and, formed a good barrier to oxygen. The combination of low solubility under high moisture conditions and the low oxygen permeability of CO2-casein films relative to other protein films and synthetic polyethylene films suggest that CO2- casein films may be a replacement for synthetic films in some applications. This research
addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Calcium casein derived from milk protein, has characteristics that make it a suitable biodegradable polymer for use in films and coatings. The technology for making these films on a large-scale is unknown at this time, because the drying kinetics are not understood. Drying curves for films comprised of calcium caseinate and glycerol were determined and an instrumental color measurement to monitor and detect film initiation and formation was developed showing that drying time could be cut in half. With these data, a continuous process can be developed which will permit the commercial production of biodegradable polymer coatings made from a dairy product. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a.
New Product Technology and 2c. New and Improved Processes and Feedstocks. Edible films made from proteins or carbohydrates have potential as replacements for synthetic films in some applications, but their use in products is limited because the technology for making them on a large- scale basis is unknown. In this study, researchers from the Dairy Processing and Products Research Unit, Eastern Regional Research Center, ARS, determined some of the relevant parameters for producing edible films made from calcium caseinate and carbon dioxide casein, modified caseins derived from milk protein. These parameters include: determination of a suitable casein solution feed system, properties of belt materials required to create the films and process parameters, such as, solution feed rate, spreading mechanism, and belt speed. With this information, a continuous, large-scale process can be developed which will permit the commercial production of biodegradable polymer films made from a dairy
product. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Nonfat dry milk (NFDM), or dried skim milk, contains the milk proteins, casein and whey, and the milk sugar lactose. Edible films made from NFDM tend to be brittle and unstable because of the low protein content relative to that in films made from milk proteins alone. The Dairy Processing and Products Research Unit, Eastern Regional Research Center, ARS, substituted NFDM for calcium caseinate in films and found that NFDM can be substituted for calcium caseinate up to 30% with little loss in the physical properties of the films. Substituting NFDM for casein reduces the cost of the films and makes them more commercially competitive relative to synthetic films. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased
Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Whey fractionation program A new environmentally-sound process was developed to separate the whey proteins into two fractions because existing processes contaminate the products with acids or salts. Experiments were performed that used CO2 to separate the whey proteins into two enriched fractions: an alpha- enriched fraction consisting mainly of alpha-lactalbumin and a fraction consisting mainly of beta-lactoglobulin. The alpha-enriched fraction containing over 60% of the alpha-lactalbumin and a beta-enriched fraction containing over 90% of the beta-lactoglobulin were obtained. Preliminary cost studies indicated that the cost of the fractions might be no more expensive than the cost of whey protein isolate. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and
Improved Processes and Feedstocks. Membrane filtration and centrifugation were compared as polishing methods to separate the enriched fractions obtained above from each other. Results indicated that centrifugation was preferable to membrane filtration in separating these fractions because protein losses were minimized. This information is important to those involved in protein processing. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. Studies to determine how the whey proteins will work or function in foods were performed. The alpha-enriched fraction can be easily incorporated into nutritional formulations under near neutral conditions. The beta fraction was soluble over the entire pH range studied. In most cases, the functional properties of the alpha fraction were different from that of the starting whey protein
concentrate. The amino acid analysis of this fraction closely resembled that of human milk. The fraction may be useful in a new cheese product. The beta-fraction showed enhanced emulsion stability, emulsion activity, and viscosity relative to whey protein concentrate. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and Improved Processes and Feedstocks. The gel-forming properties of the alpha-lactalbumin and the beta- lactoglobulin fractions were determined. As expected, alpha-lactalbumin does not form a gel. Beta-lactoglobulin forms gels at a lower concentration than WPC, meaning that less beta-lactoglobulin is needed in a formulation than the corresponding whey protein concentrate. This research addresses Action Plan Component 2. New Processes, New Uses and Value-Added Foods, and Biobased Products. Problem Areas 2a. New Product Technology and 2c. New and
Improved Processes and Feedstocks. 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? Descriptions of the casein, whey, and films processes are made available to our customers through the DPPRU website and the ARS Technology Transfer website. We have licensed the technology for our continuous process to a small company. This company had a booth at the 2004 Institute of Food Technologists Annual Meeting Food Expo to market various protein products produced using ARS carbon dioxide processing technology. Meetings were held with several companies at which details of the novel films that may be made using carbon dioxide processed proteins and progress toward a continuous film making process were discussed. Material transfer agreements were signed with two
companies. A patent was filed on the continuous film process. There are no constraints to the adoption and durability of the technology products. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Popular Publications: Healey, I. 2004. A revolutionary new food protein/nutraceutical ingredient for the food and beverage industries. International Food Marketing & Technology. 18(1): 4-6.
Impacts
(N/A)
Publications
- Tomasula, P.M., Konstance, R.P. 2004. The survival of foot-and-mouth disease virus in raw and pasteurized milk and milk products. Journal of Dairy Science. 87:1115-1121.
- Onwulata, C.I. 2004. High Moisture Extrusion of Whey Proteins. IFT Annual Meeting, July 12-16, 2004. Las Vegas, NV. Paper #41-4.
- KOZEMPEL, M.F., TOMASULA, P.M. DEVELOPMENT OF A CONTINUOUS PROCESS TO MAKE CASEIN FILMS. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY. 2004. V. 52(5). P. 1190-1195.
- Kozempel, M., Tomasula, P.M. 2004. IFT Annual Meeting. A continuous process for biodegradable protein films. Abstract No. 67-F.
- Farrell, H.M., Jimenez-Flores, R., Bleck, G.T., Brown, E.M., Butler, J.E., Creamer, L.K., Hicks, C.L., Hollar, C.M., Ng-Kwa-Hang, K.F., Swaisgood, H. E. 2004. Nomenclature of the proteins of cows' milk - Sixth Revision. J. Dairy Science. Vol. 87:p.1641-1674.
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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? The proteins found in milk form the basis of many food products. The casein proteins form the basis for most cheeses. The whey, a watery byproduct of the cheesemaking process that contains the whey proteins, is often concentrated by further processing and used as a nutritional supplement. Only about 50% of whey proteins are utilized by the dairy industry; the rest are used as animal feed or discarded. To increase markets for the milk proteins, as well as improve the methods used to obtain proteins from agricultural commodities, new, innovative and cost- effective technologies need to be developed. The approach used will: create new processes for casein and whey protein manufacture that are competitive; ensure that the processes are environmentally sound; and ensure that the technology is sufficiently open-ended so that it can be used to manufacture proteins from other agricultural
commodities such as corn and soy. 2. How serious is the problem? Why does it matter? New technologies are required for processing of proteins because current technology leaves protein-containing waste streams that require additional treatment before further use or disposal. Treatment adds salts to the waste streams. This makes it difficult to economically recover the proteins and ensure their consistency from batch to batch. Improvements in their quality will increase demand for them in food and non-food products. New processing technologies will also allow the introduction of new protein products, in addition to milk protein products, such as corn protein concentrates and isolates, to the market. These products are not currently available for food use, because of the harsh processing methods used in wet and dry-milling operations. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? This research is relevant to component
(2) of National Program 306: New Processes, New Uses, and Value-Added Foods and Biobased Products. Specifically, this project addresses Problem Area 2a) New Product Technology and Problem Area 2c) New and Improved Processes and Feedstocks. At three stakeholder meetings, new research on utilization of whey, casein and dried or fluid milk and nonfood applications of dairy ingredients was identified as a means of solving industry utilization problems. 4. What were the most significant accomplishments this past year? A: Single Most Significant Accomplishment during FY 2003: Edible films made from proteins or carbohydrates have potential as replacements for synthetic films in some applications, but their use in products is limited because the technology for making them on a large- scale basis is unknown. In this study, researchers from the Dairy Processing and Products Research Unit, Eastern Regional Research Center, ARS, determined some of the relevant parameters for producing edible
films made from calcium caseinate and carbon dioxide casein, modified caseins derived from milk protein. These parameters include: determination of a suitable casein solution feed system, properties of belt materials required to create the films and process parameters, such as, solution feed rate, spreading mechanism, and belt speed. With this information, a continuous, large-scale process can be developed which will permit the commercial production of biodegradable polymer films made from a dairy product. B: Other Significant Accomplishments: Nonfat dry milk (NFDM), or dried skim milk, contains the milk proteins, casein and whey, and the milk sugar lactose. Edible films made from NFDM tend to be brittle and unstable because of the low protein content relative to that in films made from milk proteins alone. The Dairy Processing and Products Research Unit, Eastern Regional Research Center, ARS, substituted NFDM for calcium caseinate in films and found that NFDM can be substituted
for calcium caseinate up to 30% with little loss in the physical properties of the films. Substituting NFDM for casein reduces the cost of the films and makes them more commercially competitive relative to synthetic films. C: Significant Accomplishments/Activities that Support Special Target Populations: None. D: Progress Report: This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Energenetics International, Inc. Additional details of this research can be found in the report for the Parent CRIS 1935-41000-058-00D entitled Protein Processing Using High Pressure and Supercritical Carbon Dioxide. The proteins found in milk form the basis of many food products. The casein proteins form the basis for most cheeses. The whey, a watery byproduct of the cheesemaking process that contains the whey proteins, is often concentrated by further processing and used as a nutritional supplement. Only about 50% of whey proteins are utilized by the
dairy industry, the rest are used as animal feed or discarded. To increase markets for the milk proteins, as well as improve the methods used to obtain proteins from agricultural commodities, new, innovative and cost-effective technologies need to be developed. The approach used will: create new processes for casein and whey protein manufacture that are competitive; ensure that the processes are environmentally sound; and ensure that the technology is sufficiently open-ended so that it can be used to manufacture proteins from other agricultural commodities such as corn and soy. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Casein Program: Much of the work in this project builds on the accomplishments of the earlier research project, 1935-41000-044 that terminated in FY 2000 and was bridged to FY 2001. The accomplishments of 1935-41000-054 that are pertinent to the new project are stated in the text that follows.
Carbon dioxide (CO2) was used as an agent to remove the milk protein, casein, from milk to investigate the use of this environmentally benign solvent (CO2) as a substitute for acids that are commonly used in protein processing. In addition, the processing technology to handle CO2, which exists as a gas in nature, was developed. One of the problems solved in this study was developing new machinery so that large quantities of milk could be contacted with CO2 in a short period of time while removing the casein from the machine. This process has been licensed by a company desiring to apply the technology to corn protein. To show that using CO2 as an agent to remove casein from milk is no more expensive than using acids such as hydrochloric acid (HCl), economic studies were done. These studies showed that the operating costs for casein precipitated by CO2 (CO2-casein) are less than those for acid casein or calcium caseinate obtained using acids, if the CO2 is collected and used again.
Equipment costs are similar for the two operations. This is a significant finding because it was previously believed that CO2 processes would be prohibitively more expensive due to equipment costs. In order to build new machines that use CO2 to remove proteins from agricultural commodities such as milk, knowledge of the solubility of CO2 in milk is required. Solubility values allow engineers to calculate how much CO2 to add to a given amount of milk or protein containing solution. We measured the solubility of CO2 in milk and compared these values to known values of the solubility of CO2 in water. Solubility studies showed that the solubility of CO2 in milk was comparable to its solubility in water under most conditions, meaning that existing aqueous data may be used in design calculations. This is a significant result because data acquisition for high pressure systems represents a significant outlay in resources and researcher time. Casein removed from milk using CO2 (CO2-casein)
has a higher calcium content than casein removed from milk using an acid such as HCl. Studies showed that when CO2 is added to milk, it behaves as an acid, but the fact that it=s also a gas at high pressure seems to affect the properties of water in the immediate vicinity of the casein. Milk is about 90% water. This causes it to separate from the milk sooner than it does if HCl is used. This is significant because it shows that the pressure component preserves the calcium content of the casein. Most protein films dissolve readily in water. Films were made from the CO2-casein derived from milk, and yielded a product that is barely soluble in water and is much less permeable to water than films made from the milk salt, calcium caseinate. This is significant because additional chemicals do not have to be added to decrease the film=s solubility in water. The effectiveness of the CO2-casein film as a moisture barrier for food use was compared against a calcium caseinate film by
dipping potatoes in either a CO2-casein solution or a calcium caseinate solution before frying them in oil. The moisture loss and oil-uptake of the potatoes were measured. Potatoes coated in the CO2-casein solution absorbed significantly less oil and lost less water than the calcium caseinate coated potatoes. Films made from synthetic polymers are often loaded with material for controlled release products, ranging from scents to drugs. The material in the film may be chemically attached to the polymer or held by its structure. In experiments to determine the applicability of CO2-casein films for this application, CO2-casein films, wet or dry, were added to a reactor along with a dye. Conditions were identified in which the dye penetrated the films. If the dye washed off, it obviously was not attached to the film. If it did not, it may have reacted with the casein. These experiments showed that reactions for modification of proteins might be facilitated by gas interaction,
instead of by environmentally undesirable solvents. Chemical reactions have been carried out using CO2-casein and calcium caseinate. The purpose was to detect differences in the two caseins, which were separated from milk using either CO2 or HCl. This information will be used as the basis for modifications of proteins to be tailored for different applications. The results indicate that CO2-casein has a more organized structure than acid casein. This gives casein a lower water solubility that may make it useful in an application as a hydrogel in a controlled release formulation. The feasibility of using commercial acid casein or CO2-casein developed using our high-pressure technology as replacements for the synthetic polymers that are used commercially in controlled release products was tested. Controlled release products slowly release drugs or ingredients from a film, patch or gel. In our experiments, gels of either casein and gelatin containing the drug, theophylline, were made
and the release of theophylline was measured. The studies showed that the release of the drug from the casein/gelatin gel was comparable to that of release from materials made from synthetic polymers. This initial study demonstrates that casein/gel structures have the potential of replacing synthetic materials in release applications, not only in the drug industry, but in food formulations, room fresheners, and other applications where timed release is required, such as in pesticide release. Plastic wraps are used on foods to extend their shelf-life by preventing moisture loss and by protecting them from oxidation. Protein films, which have been proposed as replacements for plastic wraps, are good oxygen barriers but dissolve readily in water, which limits their use as moisture barriers. In our studies, films prepared from carbon dioxide- casein, a form of the casein developed in our laboratory, were found to be barely soluble in water; have good moisture barrier properties compared
to films made from other protein films; and, formed a good barrier to oxygen. The combination of low solubility under high moisture conditions and the low oxygen permeability of CO2-casein films relative to other protein films and synthetic polyethylene films suggest that CO2- casein films may be a replacement for synthetic films in some applications. Calcium caseinate, a modified casein derived from milk protein, has characteristics that make it a suitable biodegradable polymer for use in films and coatings. The technology for making these films on a large- scale is unknown at this time, because the drying kinetics are not understood. Drying curves for films comprised of calcium caseinate and glycerol were determined and an instrumental color measurement to monitor and detect film initiation and formation was developed showing that drying time could be cut in half. With these data, a continuous process can be developed which will permit the commercial production of biodegradable
polymer coatings made from a dairy product. Whey fractionation program: A new environmentally-sound process was developed to separate the whey proteins into two fractions because existing processes contaminate the products with acids or salts. Experiments were performed that used CO2 to separate the whey proteins into two enriched fractions: an alpha- enriched fraction consisting mainly of alpha-lactalbumin and a fraction consisting mainly of beta-lactoglobulin. The alpha-enriched fraction containing over 60% of the alpha-lactalbumin and a beta-enriched fraction containing over 90% of the beta-lactoglobulin were obtained. Preliminary cost studies indicated that the cost of the fractions might be no more expensive than the cost of whey protein isolate. Membrane filtration and centrifugation were compared as polishing methods to separate the enriched fractions obtained above from each other. Results indicated that centrifugation was preferable to membrane filtration in separating
these fractions because protein losses were minimized. This information is important to those involved in protein processing. Studies to determine how the whey proteins will work or function in foods were performed. The alpha-enriched fraction can be easily incorporated into nutritional formulations under near neutral conditions. The beta fraction was soluble over the entire pH range studied. In most cases, the functional properties of the alpha fraction were different from that of the starting whey protein concentrate. The amino acid analysis of this fraction closely resembled that of human milk. The fraction may be useful in a new cheese product. The beta-fraction showed enhanced emulsion stability, emulsion activity, and viscosity relative to whey protein concentrate. The gel-forming properties of the alpha-lactalbumin and the beta- lactoglobulin fractions were determined. As expected, alpha-lactalbumin doesn=t form a gel. Beta-lactoglobulin forms gels at a lower
concentration than WPC, meaning that less beta-lactoglobulin is needed in a formulation than the corresponding whey protein concentrate. 6. What do you expect to accomplish, year by year, over the next 3 years? FY 2004 Modify the dryer and develop feed and collection systems to make the drying process continuous. Optimize the process. Adapt the continuous drying process to casein produced by high pressure carbon dioxide. Examine the drying phase of the film making process. Collect kinetic data for whey protein fractionation scale up studies. Make preliminary runs for carbon dioxide protein studies. This project is coded to NP 306 which is currently involved in the OSQR Review Process. 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? Descriptions of
the casein, whey, and films processes are made available to our customers through the DPPRU website and the ARS Technology Transfer website. We have licensed the technology for our continuous process to a small company. Meetings were held with several companies at which details were disclosed of the CO2 continuous protein process and progress toward a continuous film making process. Material transfer agreements were signed with two companies. An invention disclosure was also filed. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Popular Publications: Anonymous. Making water-resistant coatings from milk. Chemical Engineering Progress. 2002. v. 97(10). p. 15. Casein forms water-resistant packaging film. Industrial Bioprocessing Alert. June 20, 2003.
Impacts
(N/A)
Publications
- Kozempel,M., McAloon,A., Tomasula,P.M. Drying kinetics of calcium caseinate. J.Agric.Food Chem. 2002. v. 52. p.773-776.
- Olson,D.W., Van Hekken, D.L., Tunick,M.H., Tomasula,P.M., Molina-Corral,F. J., Gardea,A.A. Effects of milk pasteurization and aging on the functional properties of Mexican Mennonite Cheese. J.Dairy Sci. 2003. v. 86 (Suppl.l) :Abstract p.366.
- Van Hekken, D.L., Tunick, M.H., Molina-Corral, F.J., Gardea,A.A., Tomasula, P.T. Functional and rheological attributes of Hispanic-style cheeses. J. Dairy Sci. 2003. v. 86(Suppl.l):Abstract p. 81-82.
- Tomasula,P.M., Kozempel,M.F., McAloon,A.J. Development of a semi- continuous calcium caseinate film process. 2003. International Food Technologists Meeting. Paper No. 95-l331.
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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? The proteins found in milk form the basis of many food products. The casein proteins form the basis for most cheeses. The whey, a watery byproduct of the cheesemaking process that contains the whey proteins, is often concentrated by further processing and used as a nutritional supplement. Only about 50% of whey proteins are utilized by the dairy industry, the rest are used as animal feed or discarded. To increase markets for the milk proteins, as well as improve the methods used to obtain proteins from agricultural commodities, new, innovative and cost- effective technologies need to be developed. The approach used will: create new processes for casein and whey protein manufacture that are competitive; ensure that the processes are environmentally sound; and ensure that the technology is sufficiently open-ended so that it can be used to manufacture proteins from other agricultural
commodities such as corn and soy. 2. How serious is the problem? Why does it matter? New technologies are required for processing of proteins because current technology leaves protein-containing waste streams that require additional treatment before further use or disposal. Treatment adds salts to the waste streams. This makes it difficult to economically recover the proteins and ensure their consistency from batch to batch. Improvements in their quality will increase demand for them in food and non-food products. New processing technologies will also allow the introduction of new protein products, in addition to milk protein products, such as corn protein concentrates and isolates, to the market. These products are not currently available for food use, because of the harsh processing methods used in wet and dry-milling operations. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? This research is relevant to National
Program 306: New Uses, Quality and Marketability of Animal and Plant Products and supports the New Processes, New Uses, and Value-Added Biobased Products National Program Component. Collaboration with EnerGenetics, Inc. on building a plant utilizing carbon dioxide technology and At three stakeholder meetings, new research on utilization of whey and dried or fluid milk was identified as needed to solve industry utilization problems. 4. What was your most significant accomplishment this past year? A: Single Most Significant Accomplishment during FY 2002 year: Calcium caseinate, a modified casein derived from milk protein, has characteristics that make it a suitable biodegradable polymer for use in films and coatings. The technology for making these films on a large- scale is unknown at this time, because the drying kinetics or rate at which the films dry are not understood. Researchers from the Dairy Processing and Products Research Unit, ERRC, USDA, determined the drying curves for
films comprised of calcium caseinate and glycerol, developed an instrumental color measurement to monitor and detect film initiation and formation, and was able to cut the drying time in half. With these data, a continuous process can be developed which will permit the commercial production of biodegradable polymer coatings made from a dairy product. B: Other Significant Accomplishments: None. 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? Casein Program Much of the work in this project builds on the accomplishments of the earlier research project, 1935-41000-044 that terminated in FY 2000 and was bridged to FY 2001. The accomplishments of 1935-41000-054 that are pertinent to the new project are stated in the text that follows. Carbon dioxide (CO2) was used as an agent to remove the milk protein, casein, from milk to investigate the
use of this environmentally benign solvent (CO2) as a substitute for acids that are commonly used in protein processing. In addition, the processing technology to handle CO2, which exists as a gas in nature, was developed. One of the problems solved in this study was developing new machinery so that large quantities of milk could be contacted with CO2 in a short period of time while removing the casein from the machine. This process has been licensed by a company desiring to apply the technology to corn protein. To show that using CO2 as an agent to remove casein from milk is no more expensive than using acids such as hydrochloric acid (HCl), economic studies were done. These studies showed that the operating costs for casein precipitated by CO2 (CO2-casein) are less than those for acid casein or calcium caseinate obtained using acids, if the CO2 is collected and used again. Equipment costs are similar for the two operations. This is a significant finding because it was
previously believed that CO2 processes would be prohibitively more expensive due to equipment costs. In order to build new machines that use CO2 to remove proteins from agricultural commodities such as milk, knowledge of the solubility of CO2 in milk is required. Solubility values allow engineers to calculate how much CO2 to add to a given amount of milk or protein containing solution. We measured the solubility of CO2 in milk and compared these values to known values of the solubility of CO2 in water. Solubility studies showed that the solubility of CO2 in milk was comparable to its solubility in water under most conditions, meaning that existing aqueous data may be used in design calculations. This is a significant result because data acquisition for high pressure systems represents a significant outlay in resources and researcher time. Casein removed from milk using CO2 (CO2-casein) has a higher calcium content than casein removed from milk using an acid such as HCl. Studies
showed that when CO2 is added to milk, it behaves as an acid, but the fact that it's also a gas at high pressure seems to affect the properties of water in the immediate vicinity of the casein. Milk is about 90% water. This causes it to separate from the milk sooner than it does if HCl is used. This is significant because it shows that the pressure component preserves the calcium content of the casein. Most protein films dissolve readily in water. Films were made from the CO2-casein derived from milk, and yielded a product that is barely soluble in water and is much less permeable to water than films made from the milk salt, calcium caseinate. This is significant because additional chemicals do not have to be added to decrease the film's solubility in water. The effectiveness of the CO2-casein film as a moisture barrier for food use was compared against a calcium caseinate film by dipping potatoes in either a CO2-casein solution or a calcium caseinate solution before frying them
in oil. The moisture loss and oil-uptake of the potatoes were measured. Potatoes coated in the CO2-casein solution absorbed significantly less oil and lost less water than the calcium caseinate coated potatoes. Films made from synthetic polymers are often loaded with material for controlled release products, ranging from scents to drugs. The material in the film may be chemically attached to the polymer or held by its structure. In experiments to determine the applicability of CO2-casein films for this application, CO2-casein films, wet or dry, were added to a reactor along with a dye. Conditions were identified in which the dye penetrated the films. If the dye washed off, it obviously was not attached to the film, if it did not, it may have reacted with the casein. These experiments showed that reactions for modification of proteins might be facilitated by gas interaction, instead of by environmentally undesirable solvents. Chemical reactions have been carried out using
CO2-casein and calcium caseinate. The purpose was to detect differences in the two caseins, which were separated from milk using either CO2 or HCl. This information will be used as the basis for modifications of proteins to be tailored for different applications. The results indicate that CO2-casein has a more organized structure than acid casein. This gives casein a lower water solubility that may make it useful in an application as a hydrogel in a controlled release formulation. The feasibility of using commercial acid casein or CO2-casein developed using our high-pressure technology as replacements for the synthetic polymers that are used commercially in controlled release products was tested. Controlled release products slowly release drugs or ingredients from a film, patch or gel. In our experiments, gels of either casein and gelatin containing the drug, theophylline, were made and the release of theophylline was measured. The studies showed that the release of the drug from
the casein/gelatin gel was comparable to that of release from materials made from synthetic polymers. This initial study demonstrates that casein/gel structures have the potential of replacing synthetic materials in release applications, not only in the drug industry, but in food formulations, room fresheners, and other applications where timed release is required, such as in pesticide release. Plastic wraps are used on foods to extend their shelf-life by preventing moisture loss and by protecting them from oxidation. Protein films, which have been proposed as replacements for plastic wraps, are good oxygen barriers but dissolve readily in water, which limits their use as moisture barriers. In our studies, films prepared from carbon dioxide- casein, a form of the casein developed in our laboratory, were found to be barely soluble in water; have good moisture barrier properties compared to films made from other protein films; and, formed a good barrier to oxygen. The combination of
low solubility under high moisture conditions and the low oxygen permeability of CO2-casein films relative to other protein films and synthetic polyethylene films suggest that CO2- casein films may be a replacement for synthetic films in some applications. Whey fractionation program A new environmentally-sound process was developed to separate the whey proteins into two fractions because existing processes contaminate the products with acids or salts. Experiments were performed that used CO2 to separate the whey proteins into two enriched fractions: an alpha- enriched fraction consisting mainly of alpha-lactalbumin and a fraction consisting mainly of beta-lactoglobulin. The alpha-enriched fraction containing over 60% of the alpha-lactalbumin and a beta-enriched fraction containing over 90% of the beta-lactoglobulin were obtained. Preliminary cost studies indicated that the cost of the fractions might be no more expensive than the cost of whey protein isolate. Membrane filtration
and centrifugation were compared as polishing methods to separate the enriched fractions obtained above from each other. Results indicated that centrifugation was preferable to membrane filtration in separating these fractions because protein losses were minimized. This information is important to those involved in protein processing. Studies to determine how the whey proteins will work or function in foods were performed. The alpha-enriched fraction can be easily incorporated into nutritional formulations under near neutral conditions. The beta fraction was soluble over the entire pH range studied. In most cases, the functional properties of the alpha fraction were different from that of the starting whey protein concentrate. The amino acid analysis of this fraction closely resembled that of human milk. The fraction may be useful in a new cheese product. The beta-fraction showed enhanced emulsion stability, emulsion activity, and viscosity relative to whey protein concentrate.
The gel-forming properties of the alpha-lactalbumin and the beta- lactoglobulin fractions were determined. As expected, alpha-lactalbumin doesn't form a gel. Beta-lactoglobulin forms gels at a lower concentration than WPC, meaning that less beta-lactoglobulin is needed in a formulation than the corresponding whey protein concentrate. 6. What do you expect to accomplish, year by year, over the next 3 years? The sequence of project accomplishments reported in last year's annual report was reprioritized after its submission. In FY 2003, new knowledge for continuous production of protein films will be available. Preliminary experiments suggest that the films will work best as part of a web-coating system and may introduce a cost effective, non-food technology that utilizes proteins. In FY 2004, new knowledge of dairy protein interactions in supercritical fluids will be available and will demonstrate that benign processing conditions may be used to modify proteins. In FY 2005, a new
large-scale reactor will be designed to produce large amounts of the enriched alpha-lactalbumin and beta-lactoglobulin fractions for our customers and stakeholders. Kinetic data will be obtained for the fractionation step to assist in optimizing its recovery. We expect to improve the recovery of the alpha-lactalbumin to lower the economics of the process further. 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? Descriptions of the casein, whey, and films processes are made available to our customers through the DPPRU website and the ARS Technology Transfer website. We have licensed the technology for our continuous process to a small company. An Over the Top grant was awarded to assist our licensee in bringing the technology to full commercialization. 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) Popular Publications: Milk protein used to make edible, water-resistant film. ARS News and Information website, August 6, 2002. USDA develops new edible film. Institute of Food Technologists Weekly Newsletter. August 8, 2002. Use of milk protein to make an edible, water-resistant film. The USDA Agricultural Research Service. Food Industry Environmental Network, Jack Cooper, August 8, 2002.
Impacts
(N/A)
Publications
- Tomasula, P.M. Dairy Research Priorities at USDA. American Dairy Science Association. Fifth Discover Conference on Food Animal Agriculture: Milk, Dairy Ingredients and Dairy Foods for the New Decade. 2002. Abstract. p.1.
- Tomasula, P.M. Edible, water-solubility resistant casein masses. US Patent No. 6,379,726.
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