Progress 10/01/09 to 12/31/11

Outputs
OUTPUTS: The main activities of this project were conducting and analyzing experiments involving use of edible films and coatings to improve food safety and quality and minimize packaging waste and cost. This included mentoring of the graduate students and post-doctoral scholars who conducted and analyzed the experiments. The areas of experimentation and related mentoring included: 1) Producing edible films from whey protein using the same extruder technology as used in the formation of synthetic plastic films. Whey protein is extracted from whey, which is the byproduct of cheese production. The heat sealability of whey protein films was also investigated and the strengths of the heat seals were then determined to explore potential of forming edible films into food pouches for protecting food while reducing package waste. 2) Blending of whey protein with beeswax microparticles to produce composite edible films, with the goal of improving film strength and barrier to moisture and oxygen. 3) Blending of polysaccharide fractions and specific polysaccharides with whey protein to make blend films. The goal was determining the effect of blend composition on mechanical properties, water vapor permeability and oxygen permeability of the resulting blend films. 4) Incorporation of the antioxidant ascorbic acid in whey protein films to determine whether the ascorbic acid would complement the whey protein film oxygen barrier and thus improve the whey protein film ability to protect foods from oxidation. 5) Determina-tion of the ability of coatings based on whey protein to reduce the amount of fat taken up by foods during the frying process. This study investigated the use of whey protein as a coating, in combination with conventional batter and breading ingredients, for fat-update reduction in fried chicken. 6) Determination of the ability of coatings based on whey protein to replace the synthetic coatings presently used to provide an oil barrier for paperboard and pulpboard packaging used for butter, cheese-containing and other oil-containing food products. Results of the experiments conducted were published in peer-reviewed journals and presented at professional meetings. The publications and presentations reached a diverse audience of potential food industry users of the research. In addition, an encyclopedia section and a book chapter were written that give overviews of edible packaging materials, including whey protein films and coatings. PARTICIPANTS: Dr. John M. Krochta, faculty member in the Dept. of Food Science & Technology and the Dept. of Biological & Agricultural Engineering, directed this project and mentored the graduate students and post-doctoral students who conducted the experiments. Ms. Ann Dragich was a graduate student working on her M.S. in Food Science. She is presently a Food Product Development Scientist with PepsiCo. Dr. Veronica Hernandez was a graduate student working on her Ph.D. in Biological Systems Engineering in the area of extruded whey protein films. She presently has a position as Research Assistant with the School of Packaging at Michigan State University. Dr. Theeranun Janjarasskul was a graduate student working on her Ph.D. in Food Science in the areas of antioxidant-incorporated and composite whey protein films. She presently has a faculty position at Chulalongkorn University in Thailand. Ms. S. H. Lau was an undergraduate student assisting Dr. Yoo with some of her experiments. Ms. Lau is now continuing her studies in Food Science. Dr. Seacheol Min was a post-doctoral scholar who planned and conducted the experiments on the incorporation of beeswax microparticles in whey protein films. He now has a faculty position at the Seoul Women's University in Korea. Dr. Arunya Prommakool was a graduate student working on her Ph.D. in Food Science. She now has a faculty position at Kasetsart University, Thailand. Dr. Tanaboon Sajjaanantakul is a Professor at Kasetsart University, Thailand. Dr. Sajjaanantakul co-advised Dr. Prommakool on her Ph.D. research. Dr. K. Tananuwong is a Professor at Chulalongkorn University of Thailand. She was a collaborator on some of the research of Dr. Janjarasskul. Dr. SeungRan Yoo was a Post-doctoral Scholar working to increase her understanding of edible polymer films and coatings. She presently holds another Post-doctoral Scholar position at the University of California, Davis. TARGET AUDIENCES: Target audiences for this research project include: Agriculture and food industry companies and their employees who are working to improved food safety and quality while reducing packaging waste and cost. Scientific communities who perform research on proteins, films and coatings, multi-component composite systems, and packaging systems. Efforts to disseminate knowledge from this project include: Presentations of research results at the annual Institute of Food Technologists national meeting. Attendance at meetings of food industry associations. Publication of research results in peer-reviewed scientific journals. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The experiments described above produced the following new fundamental and applied knowledge that was presented at professional meetings and published in peer-reviewed journals: 1) Whey protein films can be made using the same type of extruder technology used to manufacture synthetic plastic films. Research also showed that whey protein films can be heat sealed into pouches that have sufficient strength and barrier properties to protect foods. This opens up new application possibilities for whey protein films. 2) Adding beeswax microparticles to whey protein improves properties of the resulting films. 3) Blends of whey protein with polysaccharide fractions have lower oxygen permeability than films made from whey protein or polysaccharides alone. Furthermore, compared to whey protein film, films made from blends of whey protein and polysaccharides have improved flexibility and stretchability. Blends of whey protein with specific polysaccharides such as methyl cellulose, starch and alginate can have better overall properties compared to films made from the individual components. Such blend films with their improved properties open up both new fundamental research on films made from blends of proteins and polysaccharides and also new application possibilities where edible films or coatings could replace some of the packaging required to protect foods. 4) Incorporation of the antioxidant ascorbic acid in whey protein film complements the film oxygen barrier of whey protein film and thus improves its ability to protect food from oxidation. This complementary oxygen-barrier and oxygen-scavenging ability increases the applicability of ascorbic acid incorporated whey protein film to protecting food from oxidative rancidity. 5) Whey protein-based coatings can reduce fat-uptake during chicken frying by over 30%. This information creates new opportunities for commercial development of low-fat fried foods. 6) Whey protein-based coatings on pulpboard trays, used for packaging and microwaving frozen food products containing cheese and other oily components, produce the same good barrier to oil as synthetic fluorinated hydrocarbon coating. Whey protein-based coatings on paperboard, used for packaging butter, have the same good barrier to oil as synthetic polyethylene coating. This information creates new opportunities for replacing synthetic coatings with renewable natural whey protein-based coatings, thus utilizing sustainable coating materials and making coated pulpboard and paperboard recyclable.

Publications

• Hernandez-Izquierdo, V. M. and J. M. Krochta. 2009. Thermal transitions and heat sealing of glycerol-plasticized whey protein films. Packaging Technology and Science. 2009(22):255-260.
• Min, S., T. Janjarasskul and J. M. Krochta. 2009. Whey protein-beeswax layered composite film tensile and moisture barrier properties. J. Science Food & Agriculture. 89:251-257.
• Krochta, J. M. 2009. Films, edible. In The Wiley Encyclopedia of Packaging Technology. K. Yam (ed.) John Wiley & Sons, Inc., Hoboken, NJ.
• Yoo, S. R., and J. M. Krochta. 2011. Whey protein-polysaccharide blended edible film formation and barrier, tensile thermal and transparency properties. J. Science Food & Agriculture. 91:2628-2636.
• Yoo, S. R., S. H. Lau and J. M. Krochta. 2011. Grease penetration and browning resistance of pulpboard and paperboard coated with whey protein. Packaging Technology & Science. DOI:10.1002/pts.977.
• Janjarasskul, T., K Tananuwong and J. M. Krochta. 2011. Whey protein film with oxygen scavenging function by incorporation of ascorbic acid. J. Food Science. 76(9):E561-568.
• Janjarasskul, T., Sea Cheol Min and J. M. Krochta. 2011. Storage Stability of Ascorbic Acid Incorporated in Edible Whey Protein Films. J. Agricultural & Food Chem. 59(23):12428-12432.
• Yoo, S. R. and J. M. Krochta. 2012. Starch-methylcellulose-whey protein film properties. Int'l J. Food Science & Tech. 47(2):255-261.

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: The main project activities were conducting and analyzing experiments involving use of edible films and coatings to improve food safety and quality and minimize packaging waste and cost. This included mentoring of the graduate students and post-doctoral scholars who conducted and analyzed the experiments. Experiments and related mentoring included determination of the ability of coatings based on whey protein to reduce the amount of fat taken up by foods during the frying process. This study investigated the use of whey protein as a coating, in combination with conventional batter and breading ingredients, for fat-update reduction in fried chicken. Other experiments and related mentoring involved blending of polysaccharide fractions, derived from okra, with whey protein to make blend films. The goal was determining the effect of blend composition on mechanical properties, water vapor permeability and oxygen permeability of the resulting blend films. Results of the experiments conducted were published in peer-reviewed journals and presented at professional meetings. The publications and presentations reached a diverse group of potential food industry users of the research. A review paper was written that presents recent advances in edible packaging, including advances in whey protein-based films. In addition, an encyclopedia section was written that presents theory, measurements and applications of package permeability properties. The review and encyclopedia section were published in books used as references by a diverse group of students, researchers and potential food industry users of edible packaging materials for their low permeability properties. PARTICIPANTS: Dr. John M. Krochta, faculty member in the Dept. of Food Science & Technology and the Dept. of Biological & Agricultural Engineering, directed this project and mentored the graduate students who conducted the experiments. Ms. Ann Dragich was a graduate student who has been awarded a M.S. in Food Science. Her research was in the area of whey protein-based coatings that can provide a fat barrier during drying of foods. She is presently searching for a position in the food industry. Dr. Theeranun Janjarasskul was a graduate student who was awarded a Ph.D. in Food Science. Her research was in the areas of whey protein-polysaccharide blend films and antioxidant-incorporated whey protein films. She presently has a faculty position at Chulalongkorn University in Thailand. Ms. Arunya Prommakool is a graduate student working on her Ph.D. in Food Science. Here research is in the area of whey protein-polysaccharide blend films. Dr. Tanaboon Sajjaanantakul is a Professor at Kasetsart University, Thailand. Dr. Sajjaanantakul is co-advising Ms. Prommakool on her Ph.D. research. TARGET AUDIENCES: Agriculture and food industry companies and their employees who are working to reduce fat content of fried foods. Agriculture and food industry companies and their employees who are working to improve food safety and quality while reducing packaging waste and cost. Scientific communities who perform research on proteins, films and coatings, multi-component blend systems, and packaging systems. Efforts to disseminate knowledge from this project include: Presentations of research results at the annual Institute of Food Technologists national meeting. Attendance at meetings of food industry associations. Publication of research results in peer-reviewed scientific journals. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The experiments described above produced new fundamental and applied knowledge that was presented at professional meetings and published in peer-reviewed journals. Because of much interest in reducing fat intake, approaches that reduce fat-uptake during food frying have great significance for food product development and human health improvement. Research from this project that was published demonstrated that whey protein-based coatings can reduce fat-uptake during chicken frying by over 30%. This information creates new opportunities for commercial development of low-fat fried foods. Because of much interest in reducing packaging waste, edible films formed into protective food pouches or protective food coatings have generated much interest. Other published research from this project demonstrated that edible films made from blends of whey protein with polysaccharide fractions derived from okra have lower oxygen permeability than films made from whey protein or okra polysaccharides alone. Furthermore, compared to whey protein film, films made from blends of whey protein with okra polysaccharides have improved flexibility, stretchability and oxygen barrier. Such blend films with their improved properties open up both new fundamental research on films made from blends of proteins and polysaccharides and also new application possibilities where edible films or coatings could replace some of the packaging required to protect foods and make the remaining packaging more recyclable.

Publications

• Dragich, A. M. and J. M. Krochta. 2010. Whey protein solution coating for fat-update reduction in deep fried chicken breast strips. J. Food Science. 75(1):S43-S47.
• Janjarasskul, T. and J. M. Krochta. 2010. Edible packaging materials. Ann. Rev. Food Sci. Technol. 1:415-448.
• Prommakool, A., T. Sajjaanantakul, T. Janjarasskul and J. M. Krochta. 2011. Whey protein-okra polysaccharide fraction blend edible films: tensile properties, water vapor permeability and oxygen permeability. J. Science Food & Agriculture. 19(2):362-369.
• Krochta, J. M. 2011. Package Permeability. In Encyclopedia of Agriculture, Food and Biological Engineering. ( D. R. Heldman, ed.) Marcel Dekker Inc., New York.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: The main project activities were conducting and analyzing experiments involving use of edible films and coatings to improve food safety and quality and minimize packaging waste and cost. This included mentoring of the graduate students and post-doctoral scholars who conducted and analyzed the experiments. Experiments and related mentoring included producing edible whey protein films using the same extruder technology as used in the formation of synthetic plastic films. The heat sealability of these films was investigated and the strengths of the heat seals were then determined to explore potential of forming edible films into food pouches for protecting food while reducing package waste. Other experiments and related mentoring involved blending of hydroxypropyl methylcellulose with chitosan/tripolyphosphate nanoparticles and whey protein with beeswax microparticles to produce edible films, with the goal of improving film strength and barrier to moisture and oxygen. Results of the experiments conducted were published in peer-reviewed journals and presented at professional meetings. The publications and presentations reached a diverse audience of potential food industry users of the research. Finally, an encyclopedia section was written that gives an overview of edible films and coatings, including recent advances. PARTICIPANTS: Dr. John M. Krochta, faculty member in the Dept. of Food Science & Technology and the Dept. of Biological & Agricultural Engineering, directed this project and mentored the graduate students and post-doctoral students who conducted the experiments. Dr. Veronica Hernandez was a graduate student working on her Ph.D. in Biological Systems Engineering in the area of extruded whey protein films. She presently has a position as an Instructor with the National Autonomous University of Mexico. Dr. Theeranun Janjarasskul was a graduate student working on her Ph.D. in Food Science in the areas of antioxidant-incorporated and composite whey protein films. She presently has a faculty position at Chulalongkorn University in Thailand. Dr. Seacheol Min was a post-doctoral scholar who planned and conducted the experiments on the incorporation of beeswax microparticles in whey protein films. He now has a faculty position at the Seoul Women's University in Korea. Drs. M. R. De Moura, F. A. Fauze, R. Avena-Bustillos, T. H. McHugh and L. H. C. Mattoso were collaborators attached to the Western Regional Research Center, Agricultural Research Service, U.S. Dept. of Agriculture who conducted the research on incorporation of chitosan/tripolyphosphate nanoparticles in hydroxypropyl methylcellulose edible films. TARGET AUDIENCES: Agriculture and food industry companies and their employees who are working to improved food safety and quality while reducing packaging waste and cost. Scientific communities who perform research on proteins, films and coatings, multi-component composite systems, and packaging systems. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The experiments described above produced new fundamental and applied knowledge that was presented at professional meetings and published in peer-reviewed journals. Because of increased interest in reducing packaging waste, edible films formed into protective food pouches or protective food coatings have generated much interest. Such edible food pouches and coatings must have sufficient strength, moisture barrier and oxygen barrier properties to protect food. Research from this project that was published demonstrated that whey protein films could be made using the same type of extruder used to manufacture synthetic plastic films. The research also showed that the films could be heat sealed into pouches that have sufficient strength and barrier properties to protect foods. This opens up new application possibilities for whey protein films. Other published research from this project demonstrated that adding beeswax microparticles and chitosan/tripolyphosphate nanoparticles to edible whey protein and hydroxypropyl methylcellulose films, respectively, improved strength and barrier properties of the resulting films. Such composite films with their improved properties also open up new application possibilities for edible films and coatings.

Publications

• Hernandez-Izquierdo, V. M. and J. M. Krochta. 2009. Thermal transitions and heat sealing of glycerol-plasticized whey protein films. Packag. Technol. Sci. 2009; 22:255-260.
• Min, S., T. Janjarasskul and J. M. Krochta. 2009. Whey protein-beeswax layered composite film tensile and moisture barrier properties. J. Science Food & Agriculture. 89:251-257.
• De Moura, M. R., F. A. Fauze, R. J. Avena-Bustillos, T. H. McHugh, J. M. Krochta and L. H. C. Mattoso. 2009. Improved barrier and mechanical properties of novel hydroxypropyl methylcellulose edible films with chitosan/tripolyphosphate nanoparticles. J. Food Engineering. 92(2009):448-553. Krochta, J. M. 2009. Films, edible. In The Wiley Encyclopedia of Packaging Technology. K. Yam (ed.) John Wiley & Sons, Inc., Hoboken, NJ.

Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: The main activity was conducting and analyzing experiments involving use of edible films and coatings to improve food safety and quality and minimize packaging cost. This included mentoring of the graduate students and post-doctoral scholars who conducted and analyzed the experiments. Experiments conducted included incorporation of antioxidant and antimicrobial compounds in whey protein films and then demonstrating that the activities of these compounds were maintained to protect peanuts from oxidation and smoked salmon from growth of microorganisms. Other experiments and related mentoring involved producing whey protein films using the same extruder technology as used in the formation of synthetic plastic films. The strength, flexibility and stretchability of the extruded films were then determined. Other experiments and related mentoring involved blending of whey protein with hydroxypropyl methylcellulose to produce films. These blend films had greater strength than whey protein films and the same oxygen barrier as whey protein films. Finally, a book chapter was written that gave a review of research on whey protein films and coatings. Results of the experiments conducted were published in peer-reviewed journals and presented at professional meetings. The publications and presentations reached a diverse audience of potential food industry users of the research. PARTICIPANTS: Individuals who worked on the project: Dr. John M. Krochta, faculty member in the Dept. of Food Science & Technology and the Dept. of Biological & Agricultural Engineering, directed this project and mentored the graduate students and post-doctoral students who conducted the experiments. Dr. Kirsten Dangaran was a graduate students working on her Ph.D. in Food Science in the area of gloss coatings replacements for shellac. She was co-author with Dr. Krochta on an invited book chapter which summarized research on whey protein films and coatings. Dr. Jung Han was a visiting scholar who was on sabbatical from his faculty position in the Dept. of Food Science and Technology at the University of Manitoba. He now has a position as a Research Leader for the Frito-Lay company. Dr. Veronica Hernandez was a graduate student working on her Ph.D. in Biological Systems Engineering in the area of extruded whey protein films. She presently has a position as Research Scientist with Mead Johnson Nutritionals. Dr. Seacheol Min was a post-doc scholar who planned and conducted the experiments on the development of whey protein films that incorporated antimicrobial and antioxidant compounds. He now has a faculty position at the Seoul Women's University in Korea. Ms. Laura Pallas was a graduate student working on her M.S. in Food Science in the area of blend films incorporating whey protein and hydroxypropyl methylcellulose. She is presently a Ph.D. students at the University of Georgia. Partner Organizations We have received funding and dairy industry interaction through the California Dairy Research Foundation (CDRF). They are a part of the California Milk Advisory Board (CMAB), and they manage the research funds of the CMAB and the National Dairy Board, which is part of Dairy Management Inc., (DMI). Part of the research summarized in this report was funded by the UC Discovery Grant program with matching funds from the CDRF. Training or Professional Development This project has provided training and professional development for the post-doc, visiting scholar and graduate students listed above under "Individuals"/. TARGET AUDIENCES: Target Audiences and Efforts The main output of this project has been new fundamental and applications knowledge that has been targeted to the food industry. Interaction with this target audience has been at the annual national Institute of Food Technologists meeting, where we communicate through oral presentations, poster sessions, and one-on-one interactions. Interaction also occurs through visits and by e-mail. Ultimately, consumers are the group that benefits from this project, to the degree that the food industry utilizes the new knowledge we generate. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The experiments described above produced new fundamental and applied knowledge that was presented at professional meetings and published in peer-reviewed journals. Because of increased interest in food safety, our research on incorporation of natural antimicrobial compounds in whey protein films formed as coatings on foods has generated a lot of interest. We used smoked salmon as a food model in the study, because several food-borne illness outbreaks have been associated with smoked salmon. This has occurred because smoked salmon and other ready-to-eat meats are minimally processed, making them potential carriers of pathogenic microorganisms. Utilization of natural antimicrobials carried by edible coatings is a new approach for minimizing the risk of these foods. Also, many foods such as nuts are vulnerable to oxidation, due to their high polyunsaturated oil content. Thus, they must be packaged in expensive, often non-recyclable packaging, to protect them from oxygen. Incorporation of natural antioxidants in edible food coatings is a way to protect nuts from oxidation while reducing the amount of packaging required and potentially making the reduced amount of packaging more recyclable. Other presented and published research demonstrated that whey protein films could be made using the same type of extruder used to manufacture synthetic plastic films. This opens up new application possibilities for whey protein films.

Publications

• * Hernandez-Izquierdo, V. M. and J. M. Krochta 2008 Thermoplastic processing of proteins for film formation - a review. J. Food Science. 73(2): R30-R39.
• * Hernandez-Izquierdo, V. M., D. S. Reid, T. H. McHugh, J. De J. Berrios and J. M. Krochta. 2008. Thermal transitions and extrusion of glycerol-plasticized whey protein mixtures. J. Food Science. 73(4): E169-E175.
• * Min, S., T. R. Rumsey and J. M. Krochta. 2008. Diffusion of the antimicrobial lysozyme from whey protein coating on smoked salmon. J. Food Engineering. 84(2008):39-47.
• * Pallas-Brindle, L. and J. M. Krochta. 2008. Physical properties of whey protein-hydroxypropylmethylcellulose blend edible films. J. Food Science. 73(9):E446-454.
• * Dangaran, K. L. and J. M. Krochta. 2008. Whey protein films and coatings. In Whey Processing, Functionality and Health Benefits. C. Onwulata and P. Huth (eds.) Blackwell Publishing, Ames, IA.
• * Han, J. H., H.-M. Hwang, S. Min and J. M. Krochta. 2008. Coating of peanuts with edible whey protein film containing a-tocopherol and ascorbyl palmitate. J. Food Science. 73(8):E349-355.

Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: Activities: Experiments were conducted and analyzed in four areas: 1) Antimicrobial incorporation in whey protein films and coatings to improve food safety; 2 Ascorbic acid incorporation into whey protein film and coatings to protect foods from oxidation; 3) Extrusion as an efficient way of producing whey protein films that can be heat-sealed into pouches to protect foods; 4) Whey protein coatings for reducing fat-uptake during frying of foods. Products: New knowledge was obtained on the ability of antimicrobial- and antioxidant-incorporated edible whey protein films and coatings to protect foods from microorganisms and oxygen, respectively. Extrusion conditions for producing whey protein films were determined. Ability of whey protein incorporation in coatings for fried foods was clarified. A graduate student who had been working on extrusion of whey protein films received her Ph.D. Dissemination: The annual conference of the Institute of Food Technologists, held in Chicago, IL, July 28 to Aug. 1, 2007, was attended to give presentations on research achievements. The titles of the presentations were "Prediction of Listeria monocytogenes-safe-storage-time for smoked salmon coated with a whey protein film incorporating lysozyme", "Ascorbic acid stability and color change in whey protein films during storage", "Screw speed effect on extrusion system variables and mechanical properties of extruded whey protein sheets" and "Whey protein films for fat reduction in fried chicken". PARTICIPANTS: John M. Krochta - Principal Investigator; Tom R. Rumsey - Retired from UC Davis and no longer a co-PI; Ann M. Dragich - M.S. Student Researcher; Veronica M. Hernandez-Izquierdo - Ph.D. Student Researcher; Theeranun Janjarasskul - Ph.D. Student Researcher; Seacheol Min - Postdoctoral Researcher; Daniel Rauch - M.S. Student Researcher TARGET AUDIENCES: Main target audience is food industry. Information is transfered to the food industry through professional meetings, scientific publications and individual contacts.

Impacts
Antimicrobial-incorporated whey protein films and coatings: New knowledge was obtained on the minimum inhibitory concentration (MIC) of the antimicrobial compound lysozyme (LZ) incorporated in whey protein films necessary to prevent microbial growth of the pathogenic microorganism Listeria monocytogenes (Lm). In addition, a mathematical model was developed and diffusion coefficients determined to describe the movement of LZ in the films. The combined use of the experimentally-determined MIC values and the mathematical diffusion model allows prediction of the period of time during which LZ remains above the MIC on smoked salmon (PAMIC)for a given level of contamination by Lm. This method can be also used to determine an optimum film-coating thickness and the initial LZ concentration for incorporation into the film-coating to obtain a desired antimicrobial activity for a selected period of time. Antioxidant-incorporated whey protein films and coatings: New knowledge was obtained on the stability of the antioxidant ascorbic acid (AA) in AA-incorporated whey protein films during storage, as well as color changes related to the stability. The AA concentrations in all AA-WPI-films did not significantly change during storage for 32 days at 22 or 35C. There was a small yellowing of AA-WPI-films that was strongly affected by the pH of the film-forming-solution and storage temperature. The AA stability demonstrated by this study suggests feasibility that AA-WPI-film can maintain oxygen scavenging capability for a reasonably long storage time, before being used to protect foods from oxidation. The color change shown in the AA-WPI-films is related to a mechanism other than AA oxidation. Extruded whey protein films: New knowledge was obtained on the ability to form whey protein films using an extruder that can be heat sealed into edible food pouches. Extruder operation parameters such as screw speed have effects on system variables (residence time distribution, specific mechanical energy, die pressure, product temperature) and tensile properties of extruded whey protein sheets. Higher screw speeds resulted in a higher throughput with shorter mean residence times. Lower screw speeds resulted in increased tensile strength of films, probably due to a higher degree of protein cross-linking as materials were exposed to thermal and mechanical energies for longer times. The minimum residence time to form whey protein sheets was determined to be 107 seconds, corresponding to a screw speed of 275 rpm. Whey protein oil-barrier coatings for fried food: New knowledge was obtained on the ability of whey protein to form an oil-barrier coating around chicken to reduce fat uptake during frying. Whey-protein-treated fried chicken had significantly less fat in the predust-batter-breading (PBB) coating fraction than the PBB coating of control chicken. However, whey-protein-treated chicken had no difference in the fat content of the meat fraction, which was quite low in both cases. These results indicate that most of the oil-uptake during frying is into the PBB coating, and that whey protein can reduce this uptake.

Publications

• Han J. H. and J. M. Krochta. 2007. Physical properties of whey protein coating solutions and films containing antioxidants. J. Food Science. 72(5):E308-314.
• Hernandez-Izquierdo, V. V. 2007. Thermal Transitions, Extrusion, and Heat-Sealing of Whey Protein Edible Films. Ph.D. Thesis. University of California, Davis, 110 pp.
• Min, S., J. M. Krochta, T. R. Rumsey. 2007. Diffusion of thiocyanate and hypothiocyanite in whey protein films incorporating the lactoperoxidase system. J. Food Engineering. 80(2007): 1116-1124.
• Min, S. and J. M. Krochta. 2007. Ascorbic acid-containing whey protein film coatings for control of oxidation. J. Ag. & Food Chem. 55(8):2964-2969.
• Min. S. and J. M. Krochta. 2007. Edible coatings containing bioactive antimicrobial agents. In Packaging for Nonthermal Processing of Food (J. H. Han, ed). Blackwell Publishing/IFT Press. Ames, IA
• Sothornvit, R., C. W. Olson, T. H. McHugh, J. M. Krochta. 2007. Tensile properties of compression-molded whey protein sheets. J. Food Engineering. 78(2007): 855-860.
• Dangaran, K. L. and J. M. Krochta. 2007. Preventing the loss of tensile, barrier and appearance properties caused by plasticiser crystallization in whey protein films. Intl J. Food Science & Technology. 42: 1094-1100.

Progress 01/01/06 to 12/31/06

Outputs
Gloss of whey protein-sucrose films formed as coatings on confections is maintained when a sucrose-crystallization inhibitor is added to the coating formulation. The oxygen-barrier and mechanical properties of the films are also maintained. Efficiency of forming whey protein oxygen-barrier coatings on peanuts is improved by modifying the peanut surface with a surfactant and/or by gentle roughening. Coating efficiency is also enhanced by utilizing a fluidized-bed coating system, in which peanuts are suspended and tumbled in air while being sprayed intermittently with whey protein coating solution with drying in between spraying. Whey protein films and coatings that have been incorporated with natural antimicrobial compounds present in milk have been shown to inhibit several food-borne pathogenic microorganisms. The whey protein coatings hold the antimicrobial compounds at the food surface where they are needed to inhibit microbial growth. Whey protein films can also be formed as coatings in synthetic polymer films, where they improve the oxygen-barrier.

Impacts
Whey-protein film-coatings have demonstrated antimicrobial and oxygen-barrier properties. Thus, they can improve food safety and quality, as well as reduce packaging requirements. Water-based whey-protein coatings have potential for replacing ethanol-based food coatings and synthetic plastic and paper coatings, thus reducing environmental problems. Utilizing whey protein for these applications adds value to this former waste product and enhances the economic viability of the dairy industry.

Publications

• Dangaran, K. L., J. Renner-Nantz and J. M. Krochta. 2006. Whey Protein-Sucrose Coating Gloss and Integrity Stabilization by Crystallization Inhibitors. J. Food Science. 71(3):E152-157.
• Dangaran, K. L. and J. M. Krochta. 2006. Kinetics of Sucrose Crystallization in Whey Protein Films. J. Agric. & Food Chem. 54(19): 7152-7158.
• Hong, S.-I. and J. M. Krochta. 2006. Oxygen Barrier Performance of Whey Protein Coated Plastic films as Affected by Temperature, Relative Humidity, Base Film and Protein Type. J. Food Engineering. 77(2006):739-745.
• Lin, S.-Y. and J. M. Krochta. 2006. Whey Protein Coating Efficiency on Mechanically-Roughened Hydrophobic Peanut Surfaces. J. Food Science. 71(6):E270-275.
• Lin, S.-Y. and Krochta. 2006. Fluidized-Bed System for Whey Protein Film-Coating on Peanuts. J. Food Process Engineering. 29(2006):532-546.
• Min, S., L. J. Harris and J. M. Krochta. 2006. Inhibition of Salmonella enterica and Escherichia coli O157:H7 on roasted turkey by edible whey protein coatings incorporating the lactoperoxidase system. J. Food Protection. 69(4):784-793.

Progress 01/01/05 to 12/31/05

Outputs
Oxygen-barrier edible film-coatings based on whey protein have better coverage (100%) and adhesion on the hydrophobic surface of peanuts when the nuts have had mild pre-roughening and the coating solution contains surfactants to increase compatability of the coating with the peanut surface. Addition of beeswax, a relatively soft material compared to harder carnauba wax, increases the whey protein film moisture-barrier properties through two mechanisms: increasing the hydrophobic nature of the film and 2) reducing the amount of hydrophilic plasticizer-additive necessary to achieve desired film flexibility and stretchability. Natural antimicrobial compounds, such as lactoferrin, lysozyme and lactoperoxidase, maintain their microorganism-inhibiting activity when added to whey protein film-coatings. Antimicrobial-containing whey protein film-coatings were shown to inhibit Penicillium commune mold and Listeria monocytogenes, Salmonella enterica and Escherichia coli O157:H7 pathogenic bacteria.

Impacts
Whey-protein film-coatings have demonstrated antimicrobial and oxygen-barrier properties. Thus, they can improve food safety and quality, as well as reduce packaging requirements. Water-based whey-protein coatings have potential for replacing ethanol-based food coatings and synthetic plastic and paper coatings, thus reducing environmental problems. Utilizing whey protein for these applications adds value to this former waste product and enhances the economic viability of the dairy industry.

Publications

• Min, S. and J. M. Krochta. 2005. Inhibition of Penicillium commune by edible whey protein films incorporating lactoferrin, lactoferrein hydrolysate, and lactoperoxidase systems. J. Food Science. 70(3):M87-94.
• Min, S., L, J. Harris and J. M. Krochta. 2005. Listeria monocytogenes inhibition by whey protein films and coatings incorporating the lactoperoxidase system. J. Food Science. 70(7):M317-M321..
• Min, S. and J. M. Krochta. 2005. Antimicrobial effects of lactoferrin, lysozyme, and the lactoperoxidase system and edible whey protein films incorporating the lactoperoxidase system against Salmonella enterica and Escherichia coli O157:H7. J. Food Science. 70(7):M332-M338.
• Min, S., L, J. Harris and J. M. Krochta. 2005. Listeria monocytogenes inhibition by whey protein films and coatings incorporating lysozyme. J. Food Protection. 68(11):2317-2325.
• Min, S. and J. M. Krochta. 2005. Antimicrobial films and coatings for fresh fruits and vegetables. In Raw Material Safety: Fruit and Vegetables (Win Jongen, ed.), Woodhead Publishing Ltd , Cambridge, UK.
• Perez-Gago, M. B. and J. M. Krochta. 2005. Emulsion and bi-layer films. In Innovations in Food Packaging (Jung H. Han, ed.), Academic Press, UK.
• Sothornvit, R. and J. M. Krochta. 2005. Plasticizers in edible films and coatings. In Innovations in Food Packaging (Jung H. Han, ed.), Academic Press, UK.
• Talens-Oliag, P. and J. M. Krochta. 2005. Plasticizing effects of beeswax and carnauba wax on tensile and water vapor permeability properties of whey protein films. J. Food Science. 70(3):E239-243.
• Krochta, J. M., S.-Y. Lee, T. A. Trezza and K. L. Dangaran. 2005. Methods and Formulations for Providing Gloss Coatings to Foods and For Protecting Nuts from Rancidity. U.S. Patent No. 6,869,628.
• Lin, S.-Y. and J. M. Krochta. 2005. Whey protein coating efficiency on surfactant-modified hydrophobic surfaces. J. Agric. Food Chem. 53:5018-5023.

Progress 01/01/04 to 12/31/04

Outputs
The diffusion of potassium sorbate preservative in whey protein film has been found slower than in cheese. Thus, potassium sorbate contained in whey-protein coating on cheese will remain on the cheese surface longer to protect against mold growth, compared to sprayed or dusted potassium sorbate alone. Milk-derived lactoferrin, lactoferrin hydrolysate and lactoperoxidase are also natural antimicrobials. Their inhibition activities against mold are maintained when incorporated into a whey protein film. Thus, they can also prevent molding of cheese and other high-moisture foods, when incorporated into a whey protein coating. Whey protein oxygen-barrier coatings can be formed on corona-discharge-treated polyethylene, polypropylene and polyvinyl chloride plastic films. The whey protein coatings are totally transparent and highly glossy, add no color, and have excellent adhesion to the plastic films. The resulting films can potentially be recycled more easily than plastic films coated with synthetic-polymer oxygen-barrier coatings.

Impacts
Whey-protein coatings can improve food quality as well as reduce packaging requirements. Water-based whey-protein coatings have potential for replacing ethanol-based food coatings and synthetic plastic and paper coatings, thus reducing environmental problems. Utilizing whey protein for these applications adds value to this former waste product and enhances the economic viability of the dairy industry.

Publications

• FRANSSEN, L. R., RUMSEY, T. R,. and KROCHTA, J. M.. 2004. Whey protein film composition effects on potassium sorbate and natamycin diffusion. J. Food Sci. 69(5):C347-C350.
• HONG, S.-I. and KROCHTA, J. M. 2004. Whey protein isolate coating on LDPE film as a novel oxygen barrier in the composite structure. Packaging Technology & Science 17:13-21.
• HONG, S.-I., HAN, J.H., and KROCHTA, J. M. 2004. Optical and surface properties of whey protein isolate coatings on plastic films as influenced by substrate, protein concentration and plasticizer type. J. Appl. Polymer Sci. 92:335-343.
• MIN, S. and J. M. KROCHTA. 2004. Inhibition of Penicillium commune by edible whey protein films incorporating lactoferrin, lactoferrin hydrolysate, and lactoperoxidase systems. J. Food Sci. Accepted for Publicaton.

Progress 01/01/03 to 12/31/03

Outputs
Whey protein coatings on fruits and vegetables can extend shelf life and quality by modifying internal atmosphere. The modified atmosphere effect is dependent on coating thickness and on surrounding temperature and relative humidity. Aqueous whey protein coatings on chocolate have gloss comparable to imported commercial shellac coatings. Coating gloss and gloss durability depend on the type and amount of plasticizer added to the coating formulation. Whey protein oxygen-barrier coatings could be formed on corona-discharge-treated polypropylene. The resulting films can potentially be recycled more easily than polypropylene coated with synthetic-polymer oxygen-barrier coatings. Oil-barrier whey protein coatings can be formed on paper. The resulting coated paper can be recycled or biodegraded more easily than paper coated with synthetic oil-barrier coatings. Dry whey protein powder blended with an appropriate plasticizer can be molded at high temperature and pressure to a transparent film. This indicates that such films can likely by made by the same extrusion process used for synthetic polymer films. The diffusion of potassium sorbate preservative in whey protein film is slower than in cheese. Thus, potassium-sorbate contained in whey-protein coating on cheese will remain on the cheese surface longer to protect against mold growth.

Impacts
Whey-protein coatings can improve food quality as well as reduce packaging requirements. Water-based whey-protein coatings have potential for replacing ethanol-based food coatings and synthetic plastic and paper coatings, thus reducing environmental problems. Utilizing whey protein for these applications will add value to this byproduct and enhance the economic vitality of the dairy industry.

Publications

• Balagtas, J.V., F.M. Hutchinson, J.M. Krochta and D.A. Sumner. 2003. Anticipating market effects of new uses for whey and evaluating returns to research and development. J. Dairy Sci. 86(5):1662-1672.
• Cisneros-Zevallos, L. and Krochta, J.M. 2003. Whey protein coatings for fresh fruits and relative humidity effects. J. Food Sci. 68(1):176-181.
• Cisneros-Zevallos, L. and Krochta, J.M. 2003. Dependence of coating thickness on viscosity of coating solution applied to fruits and vegetables by dipping method. J. Food Sci. 68(2):503-10.
• Dangaran, K.L. and Krochta, J.M. 2003. Aqueous whey protein coatings for panned products. The Manufacturing Confectioner 83(1):61-65.
• Hong, S.-I. and Krochta, J.M. 2003. Oxygen barrier properties of whey protein isolate coatings on polypropylene films. J. Food Sci. 68(1):224-228.
• Franssen, L.R. and Krochta, J.M. 2003. Edible Coatings Containing Natural Antimicrobials for Processed Foods. p. 250-262. IN: S. Roller (ed.), NATURAL ANTIMICROBIALS FOR THE MINIMAL PROCESSING OF FOODS, CRC Press, Boca Raton, Florida.
• Krochta. J.M. 2003. Package permeability. p. 720-726. IN: D.R. Heldman (ed.), ENCYCLOPEDIA OF AGRICULTURAL, FOOD, AND BIOLOGICAL ENGINEERING, Marcel Dekker, Inc., New York.
• Lin, S.-Y. and Krochta, J.M. 2003. Plasticizer effect on grease barrier and color properties of whey-protein coatings on paperboard. J. of Food Sci. 68(1):229-233.
• Sothornvit, R., Olsen, C.W., McHugh, T.H. and Krochta, J.M. 2003. Formation conditions, water-vapor permeability and solubility of compression-molded whey protein films. J. Food Sci. 68(6):1985-1989.

Progress 01/01/02 to 12/31/02

Outputs
Water-based whey-protein film-coatings for chocolate had gloss comparable to imported commercial alcohol-based shellac coatings. Consumer tests indicated a preference for the whey-protein-coated chocolate comparable to shellac-coated chocolate. Work is underway to reduce the whey-protein-coating gloss-fade that is observed during long storage time. Whey-protein film-coatings on peanuts reduced the oxidative rancidity that reduces shelf life of products with peanuts. The effect was smaller than that expected based on a model of the coated peanut using whey-protein-film oxygen-permeability, revealing problems with coating adhesion and durability. Work is underway to modify both the peanut surface and coating formulations to improve coating adhesion and durability. Coatings on fresh fruits and vegetables can modify internal atmosphere to increase shelf life, but relative humidity must be controlled within a small range to maintain targeted coating oxygen and carbon dioxide permeabilities. The diffusion of potassium sorbate preservative in whey protein film is slower than in cheese. Thus, potassium-sorbate contained in whey-protein coating on cheese will remain on the cheese surface longer to protect against mold growth. Whey-protein coating on polypropylene and polyethylene had good adhesion and provided an oxygen barrier comparable to synthetic polymer coating.

Impacts
Whey-protein coatings can improve food quality, as well as reduce packaging requirements. Water-based whey-protein coatings have potential for replacing alcohol-based food coatings and synthetic plastic coatings, thus reducing environmental problems. Utilizing whey protein for these applications adds value to this former waste product and enhances the economic viability of the dairy industry.

Publications

• Cisneros-Zevallos, L. and Krochta, J.M. 2002. Internal modified atmospheres of coated fresh fruits and vegetables: Understanding relative humidity effects. J. Food Sci. 67:2792-2797.
• Hong, S.-I. and Krochta, J.M. 2002. Oxygen barrier properties of whey protein isolate coatings on polypropylene films. J. Food Sci. 67(9).
• Krochta, J.M. 2002. Proteins as raw materials for films and coatings: definitions, current status and opportunities. In: PROTEIN-BASED FILMS AND COATINGS, Gennadios, A., ed. CRC Press, Boca Raton, Florida.
• Lee, S.-Y. and Krochta, J.M. 2002. Accelerated shelf life testing of whey-protein-coated peanuts analyzed by static headspace gas chromatography. J. Agr. Food Chem. 59:2022-2028.
• Lee, S.-Y., K.L., Dangaran, J.-X., Guinard and J.M. Krochta. 2002. Consumer acceptance of whey-protein-coated versus shellac-coated chocolates. J. Food Sci. 67:2764-2769.
• Perez-Gago, M. B. and J. M. Krochta. 2002. Formation and properties of whey protein films and coatings. In: PROTEIN-BASED FILMS AND COATINGS, Gennadios, A. (ed) CRC Press, Boca Raton, Florida.
• Sothornvit, R., D. S. Reid and J. M. Krochta. 2002. Plasticizer effect on the glass transition temperature of beta-lactoglobulin films. Trans. Amer. Soc. Ag. Eng 45(5).
• Trezza, T. A. and J. M. Krochta. 2002. Application of edible protein-based coatings on nuts. In: PROTEIN-BASED FILMS AND COATINGS, Gennadios, A. (ed) CRC Press, Boca Raton, Florida.

Progress 01/01/01 to 12/31/01

Outputs
Whey protein film solubility and oxygen permeability decreased, and film strength and stretchability increased, as film-forming solution heating temperature and time increased. These property changes are likely due to increased protein chain crosslinking due to protein heat-denaturation. Compared to more-commonly-used plasticizers added to decrease film brittleness, sorbitol and sucrose had a relatively larger effect on increasing film flexibility and a smaller effect on increasing oxygen permeability, a desirable outcome that can allow optimization of film properties. The effect of adding hydrophobic beeswax on reducing the water vapor permeability of whey protein films increased as the beeswax particle size decreased, likely because of increased protein-wax interaction due to increased protein-wax interfacial area. Whey protein film-coatings on paper were shown to have excellent barrier to grease and oxygen and excellent gloss and low color, comparable to existing commercial synthetic coatings. Whey protein coatings for chocolate had gloss comparable to existing commercial chocolate coatings.

Impacts
Whey protein film-coatings formed on foods can improve food quality, as well as reduce packaging and allow for easier package recyclability. Water-based whey protein coatings have potential for replacing commercial synthetic paper coatings and alcohol-based food coatings, thus improving food quality and safety and reducing environmental problems.

Publications

• Chan, M.A and Krochta, J.M. 2001. Grease and oxygen barrier properties of whey-protein-isolate coated paperboard. Solutions (TAPPI) Oct. 2001, 57.
• Chan, M.A and Krochta, J.M. 2001. Color and gloss of whey-protein coated paperboard. Solutions (TAPPI) Oct. 2001, 58.
• Han, J. H. and Krochta, J.M. 2001. Physical properties and oil absorption of whey-protein-coated paper. J. Food Sci. 66:294-299.
• Perez-Gago, M. B and Krochta, J.M. 2001. Lipid particle size effect on water vapor permeability and mechanical properties of whey protein-beeswax emulsion films. J. Agr. Food Chem. 49:996-1002.
• Perez-Gago, M. B and Krochta, J.M. 2001. Denaturation time and temperature effects on oxygen permeability, film solubility and tensile properties of whey protein edible films. J. Food Sci. 66:705-710.
• Sothornvit, R. and Krochta, J.M. 2001. Plasticizer effect on mechanical properties of beta-lactoglobulin films. J. Food Engr. 50:149-155.
• Trezza, T. A. and Krochta, J.M. 2001. Specular reflection, gloss, roughness and surface heterogeneity of biopolymer coatings. J. Applied Polymer Sci. 79:2221-2229.
• Lee, S.-Y., Dangaran, K.L. and Krochta, J.M. 2002. Gloss stability of whey-protein/plasticizer coating formulations on chocolate surface. J. Food Sci. In Press.
• Lee, S.-Y., T. A. Trezza, J.-X. Guinard and J. M. Krochta. 2002. Whey-protein-coated peanuts assessed by sensory evaluation and static headspace gas chromatography. J. Food Sci. In Press.

Progress 01/01/00 to 12/31/00

Outputs
Whey protein isolate (WPI) films dried at 80C and 40% relative humidity (RH) had lower water vapor permeability (WVP) and similar strength(s), flexibility and stretchiness as films dried at 25C or 40C at 40% RH. Since WPI films would likely be dried at high temperature commercially, these results are quite encouraging. Hydrolyzed (low-molecular-weight) whey protein isolate (HWPI) films have lower oxygen permeability, similar WVP and higher S, as well as requiring less plasticizer (edible compounds added to improve film flexibility and stretchiness), than WPI films at comparable flexibility and stretchiness. Use of less plasticizer reduces cost of the films and coatings, as well as reducing any problems with plasticizer migration into foods. WPI film coatings had the same gloss as commercial ethanol-based shellac and zein coatings. The WPI coatings had stable gloss at 52%, 75% and 95% RH, whereas the shellac and zein coatings "blushed" at 95% RH. Surfactant type and lipid particle size both had significant effect on coating gloss. WPI coatings had lower yellowing rates than whey protein concentrate (WPC) and the same rates as commercial shellac coatings. Commercial zein coatings had the most pronounced yellow color. Thus, results indicate that WPI coatings may be used in place of commercial shellac and zein coatings for many uses, whereas WPC coatings can be used to tailor color development of a food.

Impacts
Whey protein coatings as moisture, oxygen, aroma or oil barriers on foods can improve food quality, as well as reduce packaging and allow for easier package recyclability. Water-based whey protein coatings have potential for replacing commercial alcohol-based coatings, thus reducing environmental and worker safety problems.

Publications

• Perez-Gago M.B. and Krochta J.M. 2000. Drying temperature effect on water vapor permeability and mechanical properties of whey protein-lipid emulsion films. J. Agr. Food Chem. 48(7):2687-2692.
• Sothornvit R. and Krochta J.M. 2000. Water vapor permeability and solubility of films from hydrolyzed whey protein. J. Food Sci. 65(4):700-703.
• Sothornvit R. and Krochta J.M. 2000. Oxygen permeability and mechanical properties of films from hydrolyzed whey protein. J. Agr. Food Chem. 48(9):3913-3916.
• Trezza T.A. and Krochta J.M. 2000. The gloss of edible coatings as affected by surfactants, lipids, relative humidity and time. J. Food Sci. 65(5):658-662.
• Trezza T.A. and Krochta J.M. 2000. Color stability of edible coatings during prolonged storage. J. Food Sci. 65(7).

Progress 01/01/99 to 12/31/99

Outputs
Edible films and coatings are being developed for the purpose of protecting foods from moisture change, oxygen intrusion, flavor and aroma loss, oil migration, microbial growth and mechanical damage. In addition to being excellent oxygen and aroma barriers, whey protein films were found to be excellent oil barriers. Whey protein-beeswax emulsion films are good moisture barriers, with lowest water vapor permeability at neutral pH (pH=7). At the isoelectric point (pl5), the film forming solution becomes highly viscous, preventing phase separation and related lipid interconnectivity. Use of heat-denatured whey protein results in insoluble films which are stronger, compared to native (undenatured) whey protein films which are soluble and weak. Whey protein films formed as coatings on foods have color stability, gloss and adhesion comparable to, or better than, commercial coatings. Whey protein exhibits thermal transitions that suggest films could be made by the same extrusion technology used for synthetic plastic films.

Impacts
Whey protein coatings as moisture, oxygen, aroma or oil barriers on foods can improve food quality, as well as reduce packaging and allow for easier package recyclability. Water-based whey protein coatings have potential for replacing commercial alcohol-based coatings, thus reducing worker safety and environmental problems.

Publications

• De Mulder-Johnston, C. 1998. Thermal analysis of, and oil migration through films from, whey protein isolate. PhD Dissertation, Univ. California, Davis. 58 pp.
• Han, J.H. and Krochta, J.M. 1999. Wetting properties and water vapor permeability of whey-protein-coated paper. Trans. Am. Soc. Agr. Engr. 42:1375-1382.
• Perez-Gago, M.B. and Krochta, J.M. 1999. Water vapor permeability of whey protein emulsion films as affected by pH. J. Food Sci. 64:695-698.
• Perez-Gago, M.B. and Krochta, J.M. 1999. Water vapor permeability, soluility and tensile properties of heat-denatured versus native whey protein films. J. Food Sci. 64(6).
• Trezza, T.A. 1999. Surface properties of edible, biopolymer coatings for foods: color, gloss, surface energy and adhesion. PhD Dissertation, Univ. California, Davis. 169 pp.

Progress 01/01/98 to 12/31/98

Outputs
Edible films and coatings are being developed for the purpose of protecting foods from moisture change, oxygen intrusion, flavor and aroma loss, oil migration and mechanical damage. Whey protein film moisture barrier and strength increase with film drying rate. Addition of lipid to make protein-lipid emulsion films further improves moisture barrier, by increasing film hydrophobic character and immobilizing the protein chains. Whey protein films have also been found to be excellent barriers to oxygen intrusion and aroma loss in foods. A mathematical model of coated peanuts revealed that peanut oxidative rancidity could be further reduced by reducing coating cracks. Aroma barrier property of whey protein films was found to be similar to the best synthetic aroma-barrier films at low relative humidity. Use of edible coatings as oxygen and aroma barriers on foods can simplify packaging and allow for easier package recyclability.

Impacts
(N/A)

Publications

• ALCANTARA, C.R., RUMSEY, T.R. AND KROCHTA, J.M. 1998. Drying rate effects on the mechanical and water permeability properties of whey protein films. J. Food Process Engr. 21:351-368.
• KIM, S. AND KROCHTA, J.M. 1998. Polymer chain immobilization factors for whey protein-sorbitol/beeswax edible emulsion films. In: PARADIGM FOR SUCCESSFUL UTILIZATION OF RENEWABLE RESOURCES, SESSA & WILLETT, eds., AOCS Press, IL, pp.198-213.
• MATE, J.I. AND KROCHTA, J.M. 1998. Oxygen uptake model for uncoated and coated peanuts. J. Food Engr. 35:299-312.
• MILLER, K.S. AND KROCHTA, J.M. 1998. Measuring aroma transport in polymer films. Trans. Am. Soc. Agr. Engr. 41:427-433.
• MILLER, K.S., UPADHYAYA, K. AND KROCHTA, J.M. 1998. Permeability of d-limonene in whey protein films. J. Food Sci. 63:244-247.

Progress 01/01/97 to 12/01/97

Outputs
Edible films and coatings are being developed for the purpose of protecting foods from moisture change, oxygen intrusion, flavor and aroma loss, and mechanical damage. Improvements in the moisture-barrier properties of edible protein-lipid emulsion films continued with determination that softer lipids like beeswax and a high-melting milkfat fraction perform better than harder lipids such as carnauba wax and candellia wax. Protein-lipid emulsion coatings reduced moisture loss from celery sticks. Hygroscopic (moisture-attracting) coatings on peeled carrots prevented surface discoloration during storage. Whey protein films have also been found to be excellent barriers to oxygen intrusion and aroma loss in foods. Acetylated monoglyceride coatings and whey protein coatings combined with antioxidant produced significant reduction in oxidative rancidity of walnuts, suggesting that such coatings have potential for reducing package complexity and cost while improving package recyclability.

Impacts
(N/A)

Publications

• AVENA-BUSTILLOS, R. ET AL. 1997. Water vapor resistance of red delicious apples and celery sticks coated with edible caseinate-acetylated monoglyceride films. J Food Sci 62(2):351-354.
• CISNEROS-ZEVALLOS, L. ET AL. 1997. Hygroscopic coatings control surface white discoloration of peeled (minimally processed) carrots during storage. J Food Sci 62(2):363-366,398.
• KROCHTA, J.M. 1997. Edible protein films and coatings. In: FOOD PROTEINS AND THEIR APPLICATIONS IN FOODS, DAMODARAN, S. and PAARAF, A., eds, Marcel Dekker, NY.
• KROCHTA, J.M. and DE MULDER, C.L.C. 1997. Edible and biodegradable polymer films - challenges and opportunities (a scientific status summary). Food Tech 51(2):61-74.
• KROCHTA, J.M. 1997. Edible composite moisture-barrier films. In: PACKAGING YEARBOOK: 1996, BLAKISTONE, B., ed, Natl Food Proc Assoc,
• MATE, J.I. and KROCHTA, J.M. 1997. Whey protein and acetylated monoglyceriode edible coatings: Effect on the rancidity process of walnuts. J Agr Food Chem 45(7):2509-2513.
• MILLER, K.S. and KROCHTA, J.M. 1997. Oxygen and aroma barrier properties of edible films: A review. Trends Food Sci Tech
• SHELLHAMMER, T.H. and KROCHTA, J.M. 1997. Whey protein emulsion film performance as affected by lipid type and amount. J Food Sci
• SHELLHAMMER, T.H. and KROCHTA, J.M. 1997. Water vapor barrier and rheological properties of all simulated and industrial milkfat fractions. Trans ASAE 40(4):1119-1127.

Progress 01/01/96 to 12/30/96

Outputs
Research continues to develop edible films to be used as protective food coatings, wraps or pouches. The nature of the interactions between protein polymer chains in films was explored to determine the relative importance of covalent, hydrogen, and hydrophobic bonding. Beta-lactoglobulin, the main component of whey protein, was isolated. Its film-forming and barrier properties were found to be similar to whey protein. Combining milkfat and other lipid materials with whey protein produced a large improvement in moisture-barrier properties. Whey protein coatings produced significant reduction in oxidative rancidity of dry-roasted peanuts, suggesting that such coatings have potential for reducing package complexity and cost while improving package recyclability. Similar coatings had no effect on the respiration of fresh bell peppers at high relative humidity (RH), indicating that such coatings will have greatest effect at lower RH. Whey protein coatings reduced mechanical damage to freeze-dried chicken dice. Such coated dry foods will suffer smaller losses due to breakage and may benefit from the oxygen-barrier properties of the coating.

Impacts
(N/A)

Publications

• FAIRLEY, P., MONAHAN, F. J., GERMAN, J.B. and KROCHTA, J.M. 1996. Mechanical properties and water vapor permeability of edible films from whey protein isolate and sodium dodecyl sulfate. J. Agr. Food Chem. 44(2):438-443.
• LERDTHANANGKUL, S. and KROCHTA, J.M. 1996. Edible coating effects on postharvestquality of green bell peppers. J. Food Sci. 61(1):176-179.
• MATE, J. I., SALTVEIT, M.E. and KROCHTA, J.M. 1996. Peanut and walnut rancidity: effect of oxygen concentration and relative humidity. J. Food Sci. 61(2):465-468,472.
• MATE, J. I., FRANKEL, E.N. and KROCHTA, J.M. 1996. Whey protein isolate edible coatings: effect on the rancidity process of dry roasted peanuts. J. Agr. Food Chem. 44(7):1736-1740.
• MATE, J.I. and KROCHTA, J.M. 1996. Comparison of oxygen and water vapor permeabilities of whey protein isolate and beta-lactoglobulin edible films. J. Agr. Food Chem. 44(10):3001-3004.
• ALCANTARA, C.R. 1996. Barrier and mechanical properties of whey-protein-isolate-based films: film drying rate and coated-food integrity studies. MS Thesis, Univ. California, Davis. 67 pp.
• SHELLHAMMER, T.H. 1996. Characterization and optimization of water vapor transport through whey protein-lipid edible emulsion films. PhD Dissertation, Univ. California, Davis. 148 pp.

Progress 01/01/95 to 12/30/95

Outputs
The overall goal of this project is to develop edible films based on surplus milk whey protein, surplus milkfat and other edible materials, which can be formed on the surfaces of foods as coatings or used as food wraps/pouches to prevent quality deterioration by controlling transfer of moisture, oxygen, aromas/flavors, oils, etc. in foods. In addition, such films can reduce use and improve recyclability of synthetic packaging. The thermal, mechanical and moisture-barrier properties of milkfat fractions have been determined. High-melting milkfat fractions are as effective as beeswax in reducing moisture permeability when combined with whey protein in composite films. Edible coatings reduced moisture loss and the dehydrated whitish appearance on peeled carrots. Coating walnuts, peanuts and frozen fish with edible coatings produced significant reduction in oxidative rancidity. Early results also show that whey protein films are excellent barriers to lipids and volatile flavors and, thus, have potential for reducing migration or loss of these compounds in foods.

Impacts
(N/A)

Publications

• CISNEROS-ZEVALLOS, L., SALTVEIT, M.E. and KROCHTA, J.M. 1995. Mechanism of surface white discoloration of peeled (minimally processed) carrots during storage. J. Food Sci. 60(2):320-323, 333.
• FAIRLEY, P., KROCHTA, J.M. and GERMAN, J.B. 1995. Crystal morphology of mixtures of tripalmitin and butterfat. JAOCS 72(6):693-697.
• LERDTHANANGKUL, S. 1995. Effects of edible coatings on postharvest quality of green bell peppers and common mushrooms. M.S. Dissertation, Univ. of California, Davis. 56 pp.
• MATE, J.I. 1995. Mass transfer properties of whey protein films and their effect on the rancidity process of dry nuts. Ph.D. Dissertation, Univ. of California, Davis. 125 pp.
• STUCHELL, Y.M. and KROCHTA, J.M. 1995. Edible coatings on frozen king salmon: Effect of whey protein isolate and acetylated monoglyceride on moisture loss and lipid oxidation. J. Food Sci. 60(1):28-31.
• CISNEROS-ZEVALLOS, L.A. 1995. Coating treatments and modified atmosphere packaging to improve quality of minimally processed carrots. M.S. Dissertation, Univ. of California, Davis. 76 pp.

Progress 01/01/94 to 12/30/94

Outputs
The overall goal of this project is to develop edible films based on surplus milk whey protein, surplus milkfat and other edible materials, which can be formed on the surfaces of foods as coatings or used as food wraps/pouches to prevent quality deterioration by controlling transfer of moisture, oxygen, aromas/flavors, oils, etc. in foods. In addition, such films can reduce use and improve recyclability of synthetic packaging. Important progress has been made on production of composite films from whey protein and various lipids which display improved water-barrier properties. High-melting milkfat fractions are as effective as beeswax in reducing water vapor permeability of these composite films. Edible coatings reduced moisture loss and the dehydrated whitish appearance on zucchini and peeled carrots, respectively. The excellent oxygen-barrier property of whey protein film is being utilized in coating walnuts and peanuts to reduce oxidative rancidity. Preliminary results show definite advantage of reducing oxygen exposure of these nuts. Early results also show that whey protein films are excellent barriers to organic vapors and, thus, have potential for reducing flavor/aroma loss from foods.

Impacts
(N/A)

Publications

• AVENA-BUSTILLOS, R.J., KROCHTA, J.M., SALTVEIT, M.E., ROJAS-VILLEGAS, R.J. and SAUCEDA-PEREZ, J.A. 1994. Optimization of edible coating formulations on zucchini to reduce water loss. J. Food Engr. 21:197-214.
• MCHUGH, T.H. and KROCHTA, J.M. 1994. Milk-protein-based edible films and coatings. Food Tech. 48:97-103.
• MCHUGH, T.H., AUJARD, J.-F. and KROCHTA, J.M. 1994. Plasticized whey protein edible films: water vapor permeability properties. J. Food Sci. 59:416-419, 423.
• MCHUGH, T.H. and KROCHTA, J.M. 1994. Water vapor permeability properties of edible whey protein-lipid emulsion films. JAOCS 71:307-312.
• MCHUGH, T.H. and KROCHTA, J.M. 1994. Sorbitol- versus glycerol-plasticized whey protein edible films: Integrated oxygen permeability and tensile property evaluation. J. Agric. Food Chem. 42:841-845.
• MCHUGH, T.H. and KROCHTA, J.M. 1994. Dispersed phase particle size effects on water vapor permeability of whey protein-beeswax edible emulsion films. J. Food Proc. and Pres. 18(1994):173-188.
• FAIRLEY, P., GERMAN, J.B. and KROCHTA, J.M. 1994. Phase behavior and mechanical properties of tripalmitin/butterfat mixtures. J. Food Sci. 59:321-325, 337.

Progress 01/01/93 to 12/30/93

Outputs
The overall goal of this project is to develop edible films based on surplus milk whey protein, surplus milkfat and other edible materials, which can be formed on the surfaces of food as coatings or used as food wraps to prevent quality deterioration by controlling transfer of moisture, oxygen, aromas/flavors, oils, etc. in foods. In addition, such films can reduce use an improve recyclability of synthetic packaging. Recent results show that whey protein films rival the best synthetic packaging films as oxygen barriers at low-to-moderate relative humidity. Additional progress has been made on production of emulsion films between whey protein and lipids to decrease water vapor permeability. An important new finding is that at constant lipid content in emulsion films, the water vapor barrier improves as the lipid particle size decreases. Work begun recently on milkfat has determined that the hardest milkfat fraction rivals natural waxes, and are thus good prospects for incorporation into edible films.

Impacts
(N/A)

Publications

Progress 01/01/92 to 12/30/92

Outputs
The overall goal of this project is to develop edible films based on milk casein, milk whey protein and other proteins, which can be formed on the surfaces of foods as coatings or used as food wraps to prevent quality deterioration by controlling transfer of moisture, oxygen, lipids, etc. in foods. Recent progress involves determination of the optimum conditions for producing films from whey protein isolate. Additional progress has been made on production of emulsion films between proteins (caseinates or whey protein isolate) and lipids (fatty acids, fatty alcohols, acetylated monoglycerides or waxes) with lower water vapor permeability. New data on whey protein-based films indicate that their oxygen permeabilities are lower that films with other proteins. Casein-lipid emulsion coatings on fresh fruits and vegetables were found effective in reducing moisture loss.

Impacts
(N/A)

Publications

• KROCHTA, J.M. 1992. Control of mass transfer in foods with edible coatings and films, in Advances in Food Engineering, SINGH, R.P. and WIRAKARTAKUSUMAH, M. A. eds., CRC Press, Boca Raton, FL. pp. 517-537.
• AVENA-BUSTILLOS, R.J. 1992. Evaluation and modeling of mass transfer properties of edible films produced from casein-lipid emulsions for fruit and vegetable coating applications. Ph.D. Thesis. University of California, Davis. 182 p.
• HO, B.H.P. 1992. Water vapor permeabilities and structural characteristics of casein films and casein-lipid emulsion films. M.S. Thesis. University of California, Davis. 99 p.

Progress 01/01/91 to 12/30/91

Outputs
The overall goal of this project is to develop edible films based on milk casein, milk whey protein and other proteins which can be formed on the surfaces of foods as coatings to prevent quality deterioration by controlling transfer of moisture, oxygen, lipids, etc. in foods. Moisture permeability of these proteins films has been found to increase exponentially with relative humidity, which would limit their use as moisture barriers. However, recent progress involves successful formation of emulsion films between proteins (caseinates or whey protein isolate) and either fatty acids, fatty alcohols, acetylated monoglycerides or waxes. Without exception, addition of lipids to protein films reduces permeability of the films to moisture. The large drop in moisture permeability displayed by these emulsion films indicates that a desirable bilayer laminate film forms during drying of the emulsion. Other results indicate that caseinate- and whey protein-based films are excellent oxygen and carbon dioxide barriers at low relative humidity. The production of bilayer films incorporating lipids with proteins has the potential of extending the oxygen and carbon dioxide barrier properties over a larger range of relative humidities. Scanning electron microscopy and transmission electron microscopy are being used to determine the micro-structure of these multicomponent films.

Impacts
(N/A)

Publications

Progress 01/01/90 to 12/30/90

Outputs
The overall goal of this project is to develop edible films based on milk casein, milk whey protein and other proteins which can be formed on the surfaces of foods as coatings to prevent quality deterioration by controlling transfer of moisture, oxygen, lipids, etc. in foods. Excellent films have been produced from all forms of milk casein, from whey protein isolate, and from emulsions of the caseinates or whey protein isolate with either fatty acids, fatty alcohols, acetylated monoglycerides or waxes. Among the milk protein films, magnesium and calcium caseinate films were the best barriers to moisture loss, giving the lowest permeabilities (24.7 and 26.1 g water/kPa-day-m2/mm). Treating a sodium caseinate film with calcium ascorbate buffer solution at the isoelectric point of casein ionically crosslinked the protein with calcium ion, made the film insoluble, and reduced the film permeability to moisture down to 19.0 g water/kPa-day-m2/mm. Without exception, addition of lipids to protein films reduces permeability of the films to moisture. The lowest permeability was 9.5 g water/kPa-day-m2/mm, obtained from a film produced from an emulsion of sodium caseinate and lauric acid in the ratio 2:8. The large drop in moisture permeability displayed by this emulsion film indicated that a desirable bilayer laminate film had formed during drying of the emulsion. Such bilayer laminate films have great potential in reducing moisture losses from food products.

Impacts
(N/A)

Publications

• KROCHTA, J.M. 1990. Emulsion films on food products to control mass transfer. In: FOOD EMULSION AND FOAMS: THEORY AND PRACTICE, WAN, P.J., CAVALLO, J.L., SALEEB, F.Z. and MCCARTHY, M.J., eds., AIChE Symposium Series No. 277 (v. 86).
• KROCHTA, J.M., PAVLATH, A.E. and GOODMAN, N. 1990. Edible films from casein-lipid emulsion for lightly-processed fruits and vegetables. In: ENGINEERING AND FOOD, Vol. 2, SPIESS, W.E.L. and SCHUBERT, H., eds., Elsevier Applied Sciences, NY.