Progress 10/01/00 to 09/30/05

Outputs
Manufacturers of pressure processing equipment are developing more reliable units and expanding the limits of this technology. Current units are designed for one million pressure cycles and operate at room temperature with a technology barrier at ~680 MPa. The next equipment generation will exceed 700 MPa and 100C to achieve the inactivation of bacterial spores. Bacterial spores, unlike vegetative cells, are much more resistant to pressure and require HPP processes near conventional sterilization temperature. However, a shorter processing time will result in moderate chemical changes to foods. Moreover, processing temperature will be reached by preheating to moderate temperature amd followed by compression heating. It will be lowered by decompression and therefore heated pressurization processes should cause minimum quality losses. To support this HPP research, a 2.2-liter Engineered Pressure Systems (EPSI) high pressure/high temperature vessel was installed with assistance from the OSU Department of Microbiology in Nash Hall Room 456. We improved the reliability of its pressure intensifier, upgraded the pressure transducer and gauge monitoring its operation, and will receive a new temperature measurement purchased from EPSI. We also operate a 20-liter unheated pressure vessel recently equipped with a new 40-HP pump from Avure Technologies. Both units allow now pressure come-up time of less than 1 minute, i.e., in the range of commercial interest. In collaboration with Dr. Sarker we obtained kinetic data for the inactivation of bacterial spores (Clostridium perfringens and C. sporogenes) including mechanistic interpretations of their inactivation resistance. Also completed is a study on their inactivation by commonly used sanitizers. In collaboration with Dr. Qian and Velazquez, we identified three processes at 586 MPa (1 and 3 min at 60C and 3 min at 55C) producing milk with a shelf-life exceeding 45 days under refrigeration (5C). Ongoing flavor analysis studies show that these treatments do not affect the volatile composition of milk yielding similar values to those measured for thermally pasteurized milk. Future experiments will focus on further inhibition of cooked aroma compounds by the use of three natural and one synthetic antioxidant. This will generate valuable information on improving even further the flavor of extended shelf-life (ESL) refrigerated milk and provide insights into an HPP process for shelf-stable milk using higher pressure. Our preliminary conclusion is that the flavor profile does not distinguish conventionally pasteurized milk (15-day shelf-life) from milk subjected to pressure treatments (shelf-life exceeding 45 days). Therefore, ESL refrigerated milk produced by combined heat-pressure treatments has a high probability of being accepted by consumers.

Impacts
High-pressure processing (HPP) of foods reduces and often eliminates the use of additives and chemical preservatives. In most cases, HPP requires significantly less energy than traditional heat processing. A first generation of commercial HPP equipment was developed, and a Pacific Northwest company became an industry leader (Avure Technologies, Inc.). The growth of the HPP markets was assisted by OSU graduates. For example, when a recent OSU graduate was hired by Fresherized Foods, her HPP expertise helped this company expand the range of foods produced by HPP. Improved combat rations for the U.S. military (a goal once supported by the U.S. Department of Defense) have been used as starting points for new products. HPP is used commercially to extend the shelf-life of perishable food products without affecting quality, thus creating cost savings from reduced spoilage. Food safety problems previously considered insurmountable have been solved. For example, moderate pressure can achieve significant reductions in food pathogens in addition to extending the shelf-life of fresh oysters. A goal of the industry is to move to the next generation of HPP equipment that combines moderately high temperature (~200 F) and pressures in the 100,000 psi range, producing shelf-stable foods of better quality than by conventional thermal processing. The OSU research supports this industry goal by working on the heated pressurization inactivation of bacterial spores and on the mechanisms of flavor degradation under combined heat and pressure conditions.

Publications

• Lopez, D., Mendoza-Sanchez, P., Torres, J.A., Ramos, G., Pless, R.C., Huerta-Ruelas, J. 2004. Optical rotation measurements in food industry processes. In Proceedings of the International Simposium of Metrology, Oct 25-27, Queretaro, Mexico.
• Lopez, D., Mendoza-Sanchez, P., Torres, J.A., Ramos, G., Pless, R.C., Huerta-Ruelas, J. 2004. Optical rotation measurements in food industry processes. In Proceedings of the International Simposium of Metrology, Oct 25-27, Queretaro, Mexico.
• Mendoza-Sanchez, P., Lopez, D., Kongraksawech, T., Vazquez, P., Torres, J.A., Ramirez, J.A., Huerta-Ruelas, J. 2005. Laser metrology in food related systems. Proceedings of the Eighth International Symposium on Laser Metrology, International Society for Optical Engineering, R. Rodriguez-Vera, F. Mendoza-Santoyo (editors), vol. 5776, p. 347-354.
• Mendoza-Sanchez, P., Lopez, D., Kongraksawech, T., Vazquez, P., Torres, J.A., Ramirez, J.A., Huerta-Ruelas, J. 2005. Laser metrology in food related systems. Proceedings of the Eighth International Symposium on Laser Metrology, International Society for Optical Engineering, R. Rodriguez-Vera, F. Mendoza-Santoyo (editors), vol. 5776, p. 347-354.
• Torres, J.A. 2005. Avances y oportunidades comerciales para el procesamiento por altas presiones hidrostaticas, una tecnologia de punta instalada en Mexico. Proceedings of the Ciclo de Conferencias Magistrales del Congreso de Ciencias del Instituto de Ciencias Biomedicas de la Universidad Autonoma de Ciudad Juarez, Mexico, September 5-9, 2005.
• Uresti, R.M., Velazquez, G., Vazquez, M., Ramirez, J.A., Torres, J.A. 2006. Effect of combining microbial transglutaminase and high pressure processing on the mechanical properties of restructured products from arrowtooth flounder (Atheresthes stomias). Food Chemistry 94: 202-209.
• Vazquez-Landaverde, P. A., G. Velazquez, J. A. Torres, M. C. Qian. 2005. Quantitative determination of thermally derived volatile compounds in milk using solid-phase microextraction and gas chromatography. Journal of Dairy Science. J. Dairy Sci. 88:3764-3772
• Velazquez, G., Vazquez, P., Vazquez, M., Torres, J.A. 2005. High pressure food processing applications. Ciencia y Tecnologia Alimentaria 4(5): 343-352.

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

Outputs
Consumers demand high sensory quality foods. Thermal processing provides safety and convenience but not this sensory quality. High pressure processing (HPP), a new alternative with extensive research at OSU is meeting this expectation on a worldwide basis. The improvements of thermal processes and development of alternatives such as HPP require new knowledge. For example, engineering properties and reaction kinetics are largely unknown for foods under high pressure. Success to develop this knowledge is enhanced by the sharing of expertise among engineers, food scientists and other scientists in Multistate Project NC136. In meetings of this committee, we learn about work at other institutions, receive feedback on our work and develop collaboration opportunities. To develop optical methods for food systems, Torres and Collaborator Huerta from the Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (Mexico) designed, built and tested two identical systems measuring the optical rotation (OR) of chiral compounds. The instrument was calibrated using sugar solutions and validated by monitoring sucrose hydrolysis. Characterization of commercial candies and monitoring alcoholic fermentations were used to evaluate the instrument. The high sensitivity of OR measurements and versatility of the system configuration demonstrated its potential for quality control and experimentation with food systems. The instrument is now used to study the thermal denaturation of food proteins, fermentations in real time, and monitoring protein recovery from surimi wash water by chitosan alginate complexes. Pathogenic sporeformers such as Clostridium botulinum, Clostridium perfringens and Bacillus cereus are a high-risk food safety concern. Coat protein solubilization methodologies to study bacterial spore resistance to heated pressurization have been developed by Torres to characterize spore coat effects by pressure and heat. Pressure induced pH shifting to improve HPP lethality is being investigated by Shellhammer. Microbial tolerance to lethal treatments depends on pH. In the range of typical food applications, a reduction in pH often leads to an increase in the lethal effect of HPP. Process dependent kinetic parameters affecting beer quality are also being investigated by Shellhammer. While overall hop utilization has been well defined functionally, there is a lack of published research pertaining to the actual kinetics of both the extraction of alpha acids from hops and their subsequent isomerization. Finally, Torres is seeking the application of information technologies for on-site & distance education in food process engineering. These technologies were implemented for the first time in FST 490/590 Pilot Plant Experiences in Food Processing, a required course for undergraduates majoring in Food Science and Technology. Also, much of the research accomplished by NC-136 is of direct relevance to the teaching of this course, particularly the lectures and laboratories covering thermal and pressure processing.

Impacts
Changing economic, social, and demographic conditions create a desire for new products, new packaging, more convenience, new delivery systems and safer and more nutritious foods. The greatest challenge to industry is to change fast enough to keep pace with technology advances and consumer trends. The need to improve quality and retain nutritional value has resulted in new thermal and non-thermal preservation technologies. These technologies are being investigated at OSU to produce high-value products. The demand for quality can also provide market opportunities. Oregon processors can modify technologies to achieve market advantages. An example is an effort to demonstrate that Oregon whey is superior to those produced elsewhere. Many products are fabricated from the same ingredients and it is processing which differentiate their sensory attributes. For example, a high sensory quality is a critical factor in the commercial success of foods but obesity has reached alarming levels in the USA. Our industry could profit from products that could help reduce obesity incidence replicating previous technology successes (e.g., nutrient fortified products such as iodized salt and vitamin D fortified milk). As demand for new food products containing nutraceuticals and/or new functionality are increasing, reliable means to preserve the effectiveness of these ingredients and understand their interactions with base ingredients are also urgently needed. The objectives of NC136 take on special relevance in light of these new products, technologies and challenges.

Publications

• Serrano, J., Velazquez, G., Lopetcharat, K., Ramirez, J.A. and Torres, J.A. 2004. Effect of moderate hydrostatic pressure on microstructure, texture and sensory properties of stirred curd Cheddar shreds. Journal of Dairy Science 87: 3172 - 3182
• Shook, C.M., Shellhammer, T.H., and Schwartz, S.J. 2001. Polygalacturonase, pectinesterase, and lipoxygenase activities in high pressure processed diced tomatoes. Journal of Agricultural and Food Chemistry 49(2), 664 668.
• Tay, T, Shellhammer, T.H., Yousef, A.E. and Chism, G.W. 2003. Pressure death and tailing behavior of Listeria monocytogenes strains having different barotolerances. Journal of Food Protection 66(11), 2057-2061.
• Torres, J.A. & Velazquez, G. 2004. Commercial opportunities & research challenges in the high pressure processing of foods. Journal of Food Engineering 67: 95-112
• Truong, T.T., Boff, J.M., Min, D.B., and Shellhammer, T.H. 2002. Carbon dioxide in high pressure processing: Enzymatic and chemical changes in single strength orange juice. Journal of Food Science. 67(8), 3058-3062.
• Uresti, R.M., Velazquez, G., Ramirez, J.A., Vazquez, M. & Torres, J.A. 2004. Effect of high pressure treatments on mechanical and functional properties of restructured products from arrowtooth flounder (Atheresthes stomias). Journal of the Science of Food and Agriculture 84: 1741-1749
• Uresti, R.M., Velazquez, G., Vazquez, M., Ramirez, J.A. & Torres, J.A. 2004. Effect of sugars and polyols on the functional and mechanical properties of pressure-treated arrowtooth flounder (Atheresthes stomias) proteins. Food Hydrocolloids. IN PRESS
• Malone, A.S., Wick, C., Shellhammer, T.H., and Courtney, P.D. 2003. High pressure effects on proteolytic and glycolytic enzymes involved in cheese manufacturing. Journal of Dairy Science 86, 1139-1146.
• Mendoza-Sanchez, P., Lopez, D., Ramos, G., Pless, R., Huerta-Ruelas, J. and Torres, J.A. 2004. An optical rotation measurement system to control processes in the food industry and to study thermal denaturation of food proteins. In Memorias del Simposio de Metrologia. Centro Nacional de Metrologia (CENAM), Queretaro, Mexico.
• Morales-Blancas E. F. and Torres, J.A. 2003. Activation Energy (Ea). In Encyclopedia of Agricultural and Food Engineering, p. 1-4, Heldman, D. (editor), Marcel Dekker, Inc., New York, NY.
• Morales-Blancas E. F. and Torres, J.A. 2003. Measurement of Kinetic Parameters. In Encyclopedia of Agricultural and Food Engineering, p. 1038-43, Heldman, D. (editor), Marcel Dekker, Inc., New York, NY.
• Arora, A. Chism, G. and Shellhammer, T.H. 2003. Rheology and stability of simple food emulsions treated with high pressure. Journal of Agricultural and Food Chemistry 51(9), 2591-2596.
• Boff, J.M., Troung, T.T., Min, D.B., and Shellhammer, T.H. 2003. Effect of thermal processing and carbon dioxide assisted high pressure processing on pectinmethylesterase and chemical changes in orange juice. Journal of Food Science 68(4), 1179 - 1184.
• Chew, K. 2001. Prospects for pressure processing on bacteria in Pacific oysters, Aquaculture Magazine, Nov/Dec
• Corwin, H. and Shellhammer, T.H. 2002. Combined carbon dioxide and high pressure inactivation of pectin methylesterase, polyphenol oxidase, Lactobacillus plantarum and Escherichia coli. Journal of Food Science 67(2), 697-701.
• Lopez, D., Mendoza-Sanchez, P., Kongraksawech, T., Velazquez, G., Huerta-Ruelas, J. and Torres, J.A. 2004. In-line/real-time optical polarization measurements in food systems. Journal of Food Engineering. SUBMITTED
• Lucore, L.A., Shellhammer, T.H., and Yousef, A.E. 2000. Inactivation of Listeria monocytogenes Scott A on artificially contaminated frankfurters by high pressure processing. Journal of Food Protection 63(5), 662-664.
• Malone, A.S., Shellhammer, T.H., and Courtney, P.D. 2002. High pressure effects on the viability, morphology, lysis and cell wall hydrolase activity of Lactococcus lactis subsp. cremoris. Applied and Environmental Microbiology 68(9), 4357-4363.
• Morales-Blancas, E. & Torres, J.A. 2004. WAMFoodLab. Laboratorio de Metodos Asistidos por Internet para Calculos de Ingenieria de Procesos de Alimentos. VirtualPro, April 2004.
• Morales-Blancas E. F. and Torres, J.A. 2003. Thermal Resistance Constant (z). In Encyclopedia of Agricultural and Food Engineering, p. 1030-37, Heldman, D. (editor), Marcel Dekker, Inc., New York, NY.
• Nienaber, U. and Shellhammer, T.H. 2001 High-pressure processing of orange juice: Kinetics of pectinmethylesterase inactivation. Journal of Food Science 66(2), 328-331.
• Nienaber, U. and Shellhammer, T.H. 2001. High-pressure processing of orange juice: Combination treatments and a shelf life study. Journal of Food Science 66(2), 332-336.
• Paredes, D., Morales-Blancas, E., Ah-Hen, K.S, Velazquez, G. & Torres, J.A. 2004. Crecimiento microbiano en alimentos refrigerados. In Proceedings of the International Congress of Food Safety, Reynosa, Tamaulipas, October 12-15, Mexico.
• Salas, J., Velazquez, G., and Torres, J.A. 2002. Un algoritmo para la medicion en linea de la longitud de tiras flexibles sobrepuestas. In Memorias del Simposio de Metrologia. Centro Nacional de Metrologia (CENAM). Queretaro, Mexico.
• Serrano, J., Velazquez, G., Lopetcharat, K., Ramirez, J.A. and Torres, J.A. 2004. Moderate hydrostatic pressure processing to reduce production costs of shredded cheese: Microstructure, texture and sensory properties of shredded milled curd Cheddar. Journal of Food Science. IN PRESS
• Velazquez, G., Vazquez, P. and Torres, J.A. 2004. Altas Presiones en la Industria Alimentaria: I. Consideraciones Comerciales en el Procesamiento de Alimentos por Alta Presion. In Proceedings of the International Congress of Food Safety, Reynosa, Tamaulipas, October 12-15, Mexico.
• Velazquez, G., Vazquez, P. and Torres, J.A. 2004. Altas Presiones en la Industria Alimentaria: II. Retos Actuales de Investigacion en el Procesado de Alimentos a Altas Presiones. In Proceedings of the International Congress of Food Safety, Reynosa, Tamaulipas, October 12-15, Mexico.
• Vittadini, E., Clubbs, E., Shellhammer, T.H., Vodovotz, Y. 2004. Effect of high pressure processing and addition of glycerol and salt on the properties of water in corn tortillas. Journal of Cereal Science 39(1), 109-117.
• Wick, C., Nienaber, W, Anggraeni, O, Shellhammer, T.H., Courtney, P.D. 2004. Proteolysis, texture and viable lactic acid bacteria in commercial Cheddar cheeses treated with high pressure. Journal of Dairy Research 71(2), 107-115.
• Uresti, R.M., Velazquez, G., Vazquez, M., Ramirez, J.A. & Torres, J.A. 2004. Effect of combining microbial transglutaminase and high pressure processing on the mechanical properties of restructured products from arrowtooth flounder (Atheresthes stomias). Food Chemistry. IN PRESS.
• Uresti, R.M., Velazquez, G., Vazquez, M., Ramirez, J.A. & Torres, J.A. 2004. Restructured products from arrowtooth flounder (Atheresthes stomias) using high pressure treatments. European Food Research and Technology. IN PRESS.

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

Outputs
Consumers demand today products with "freshness" while retaining nutritional value, convenience and safety. Conventional thermal processing technologies provide safety and convenience but do not yield the sensory quality of fresh foods or freshly prepared meals. High hydrostatic pressure is the only new processing alternative that can meet this consumer expectation and is satisfying this market on a worldwide basis. In spite of this progress much needs to be done to identify the most cost effective pressure-time-temperature combinations to ensuring product safety. At present, NC-136 researchers work on Listeria monocytogenes with emphasis on the determination of its inactivation kinetics and on processing aids to increase the effectiveness of pressure treatments. For example, Dr. Shellhammer is investigating the treatment of Listeria monocytogenes with membrane-active agents to counter cells pressure resistance. Dr. Torres is investigating in collaboration with Dr. Sarker (OSU Microbiology Department) and Drs. Anderson and Malencik (OSU Biochemistry and Biophysics Department), the inactivation of Clostridium perfringens spores by heated pressurization with a focus on the role of small acid soluble proteins (SASPs) and bacterial spore coat proteins. The role of pressure pulses and the increase of process effectiveness by germination promoters and surface active agents are also a central area of research. Applied research includes seafood (oyster shucking, restructured arrowtooth flounder, etc.), fruits and vegetables (fresh cut products) and dairy (acceleration and enhancement of the shreddability of natural cheeses, ESL refrigerated milk). Of particular significance is ongoing community development funding at the Astoria Seafood Laboratory where high pressure processing is being applied to establish new local business. This is a novel activity where researchers are working with a local development bank and local entrepreneurs. Work continues also on the improvement of conventional technologies. For example, Dr. Goddik is investigating the impact of processing parameters on whey powder quality attributes and identifying procedures to achieve superior performance for Oregon produced whey. Emphasis is on the effect of whey concentrate crystallization parameters on lactose crystal form and hygroscopicity and the effect of protein denaturation on viscosity of whey concentrates. Finally, Dr. Torres is seeking the application of information technologies for on-site & distance education in food process engineering to promote cooperation in the preparation of future engineers and help in the continuing education needs of current and future professionals. The two approaches being investigated are the web access to science & engineering teaching equipment and the development of calculation software via web-aided methods (WAM) for food process engineering.

Impacts
Foods consumed in the USA have a remarkable safety record; however, the current emphasis on the consumption of fresh foods has created the need for new technologies that deliver safety AND freshness. For example, fresh cut fruit salads provide many of the nutrients recommended by health experts but handling during processing and packaging leads to their contamination with pathogens. Non-pasteurized juices have sensory and health-promoting attributes that the consumer demands but are not allowed by current safety regulations which require processing ensuring a 5-log reduction in pathogen counts. Our high pressure processing research has shown that this requirement can be met by this new technology with no changes in sensory and chemical properties. The pressure processing industry has submitted a letter to regulatory agencies requesting authorization to label pressure processed juices as "fresh." The demand for quality can also be used to provide market opportunities. Oregon processors can modify product handling and processing technologies to achieve market advantages. An example is the current effort to demonstrate that Oregon whey is superior to those produced elsewhere.

Publications

• Calik, H. and Morrissey, M.T. 2002. Piling the pressure on microorganisms. Food Technology International, Vol. 1: 105-107.
• Calik, H., Morrissey, M.T., Reno, P., and An, H. 2002. Effect of high-pressure processing on Vibrio parahaemolyticus strains in pure culture and Pacific oysters. J. Food Sci. 67(4): 1506-10
• Chew, K. 2001. Prospects for pressure processing on bacteria in Pacific oysters, Aquaculture Magazine, Nov-Dec 2001
• He, H., Adams, R., Farkas, D., and Morrissey, M.T. 2002. Use of high-pressure processing for oyster shucking and shelf-life extension. J. Food Sci. 67(2): 640-45
• Morales-Blancas E. F. and Torres, J. A. 2003. Activation Energy (Ea), in Encyclopedia of Agricultural and Food Engineering, Heldman, D. (editor), Marcel Dekker, Inc., New York, NY.
• Morales-Blancas E. F. and Torres, J. A. 2003. Measurement of Kinetic Parameters, in Encyclopedia of Agricultural and Food Engineering, Heldman, D. (editor), Marcel Dekker, Inc., New York, NY.
• Morales-Blancas E. F. and Torres, J. A. 2003. Thermal Resistance Constant (z), in Encyclopedia of Agricultural and Food Engineering, Heldman, D. (editor), Marcel Dekker, Inc., New York, NY.
• Anonymous. 2003. Pressed for Success: High-Pressure Oyster Processing. Oregon Agricultural Progress, Winter Vol. 49 (1): 24-29
• Velazquez de la Cruz, G., Gandhi, K., and Torres, J.A. 2002. Hydrostatic pressure processing: A review. Biotam. 12(2): 71-78.

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

Outputs
High pressure processing (HPP) is a non-thermal process to inactivate pathogens and spoilage microorganisms in foods with minimum changes in texture, color, and flavor. Five decimal reductions in pathogens including Escherichia coli O157:H7, Salmonella typhimurium, S. enteritidis, Listeria monocytogenes, Staphylococcus aureus and Vibrio parahaemolyticus can be achieved by pressure treatments. Recent advances in equipment, successful commercial products and the increased demand for minimally processed, high quality and safe foods have lead to considerable interest in HPP technology. This is particularly true when HPP has a niche advantage over thermal processing such as in juice pasteurization. E. coli O157:H7, Salmonella, Cryptosporidium and viruses have been known to cause illness in people after consuming unpasteurized "fresh" juice. Regulations are now in place requiring the heat pasteurization of juices and ciders. These products can no longer be marketed as "fresh" and do not have the freshness attributes demanded by consumers. To satisfy this demand, the HPP industry is seeking from regulatory authorities the approval of the labeling term "fresh" for pressure-treated juices. To assist industry meet the consumer demand for "fresh" juices, we determined whether consumers could distinguish fresh and pressure-processed orange and apple juice. Freshly extracted organic juice from a local supplier (Hood River, OR) was processed at 80,000 psi for 1 min in half-gallon containers. Samples were kept refrigerated during all handling beginning at the juice processor and ending when samples were subjected to sensory and instrumental evaluations. Two sets of panelists were recruited from the Corvallis community with 101 consumers of apple juice and 221 consumers of orange juice. The fresh, unprocessed vs. fresh, HPP juice testing showed no significant difference for both juices and we concluded at the 99% confidence level that samples were significantly similar. In addition, color measurements and evaluation of the retention of the antioxidants in juice, including ascorbic acid, showed no differences.

Impacts
This study provided key supporting information for an industry petition to regulatory agencies for the claim that HPP-treated juices should be allowed to be marketed as "fresh." Consumers will benefit from having on the market a product that is safe AND meets their "freshness" quality expectation.

Publications

• No publications reported this period

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

Outputs
This project defined some of our research pursued during the period of membership in the AES Regional Committee, NC-136, "Improvement of Thermal Processes for Foods." Co-PI McGuire withdrew from committee involvement during an early year of this project; PI Kolbe withdrew from the committee in 1997 (documented in a 11-13-97 letter to Assoc. Dean Kelvin Koong), as his position and academic responsibilities changed to focus more on extension and applied research. Roughly in the fall of 1998, Assoc. Dean Bob Witters appointed Dr. Antonio Torres to represent OSU Experiment Station in this Regional Committee. In 1995, PI Kolbe served as chair of this committee and led the preparation of a 5-year renewal proposal which was successful. Annual meetings supported regional research collaboration; PI Kolbe chaired an ad-hoc committee on Differential Scanning Calorimetry and facilitated a round-robin standardized test procedure among a number of stations. He also contributed to a second ad-hoc committee that prepared standardized procedures for measuring thermal conductivity using transient techniques. Research work in thermal processes and thermal property measurement and modeling fell under this project, and is described in selected publications, listed below.

Impacts
The collaboration among top university researchers through annual multi-day informal meetings, as well as continued communication throughout the year, supported a quality of ideas and approaches that would not have been otherwise possible. Our research success in ohmic heating and electrical properties of seafoods, and thermal conductivity measurements, grew directly out of these conversations and support. The value to the surimi seafood industry, currently seeking commercial rapid methods of cooking, continues to be realized.

Publications

• Kolbe, E., Wilson, L., Hartel, R. 1996. Differential scanning calorimetry for enthalpy and transition temperatures by a round-robin method. Submitted to Journal of Food Engineering.
• AbuDagga, Y., Kolbe, E. 2000. Analysis of heat transfer in surimi paste heated by conventional and ohmic means. J. of Aquatic Food Product Technology 9(2):43-54.
• Su, A., Kolbe, E., Park, J.W. 1999. A model of heat transfer coefficients over steam-cooked surimi paste. J. of Aquatic Food Product Technology 8(3):39-53.
• Zhao, Y., Kolbe, E., Flugstad, B. 1999. A method to characterize electrode corrosion during ohmic heating. J. Food Process Engineering 22:81-89.
• Wu, H., Flugstad, B., Kolbe, E., Park, J.W., Yongsawatdigul, J. 1998. Electrical properties of fish mince during multi-frequency ohmic heating. J. Food Science 63(6):1028-1032.
• Zhao, Y., Kolbe, E., Craven, C. 1998. Simulation of onboard chilling and freezing of albacore tuna. J. of Food Science 63(5):751-755.
• Yongsawatdigul, J., Park, J.W., Kolbe, E. 1997. Kinetics of texture degradation in Pacific whiting surimi. J. Food Process Engineering 20:433-452.
• Yongsawatdigul, J., Park, J.W., Kolbe, E. 1997. Degradation kinetics of myosin heavy chain of Pacific whiting surimi. J. Food Science 62:724-728.
• AbuDagga, Y., Kolbe, E. 1997. Thermophysical properties of surimi paste at cooking temperature. J. of Food Engr. 32(3):325-337.
• Murakami, E.G., Sweat, V.E., Sastry. S.K., Kolbe,E. 1996. Analysis of various design and operating parameters of the thermal conductivity probe. J. of Food Engr. 30(1-2):209-226.
• Murakami, E.G., Sweat, V.E., Sastry, S.K., Kolbe, E., Hayakawa, K., Datta, A. 1996. Recommended design parameters for thermal conductivity probes for non frozen food materials. J. Food Engineering. 27(2):109-123.
• Yongsawatdigul, J., Park, J.W., Kolbe, E. 1995. Electrical conductivity of Pacific whiting surimi paste during ohmic heating. J. Food Sci. 60(5):922-925,935.
• Yongsawatdigul, J., Park, J.W., Kolbe, E., AbuDagga, Y., Morrissey, M.T. 1995. Ohmic heating maximizes gel functionality of Pacific whiting surimi. J. Food Science 60(1):10-14.

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

Outputs
This describes the progress of E. Kolbe. The summary of J. McGuire's accomplishments and publications are included in AES Project 457.. Our work with stabilizing frozen mince of Pacific whiting continues with tests showing that lactose in dried whey powder is potentially effective to maintain frozen storage stability. Williams Landall Ferry modeling used to describe the temperature dependence of quality change in frozen Pacific whiting gave results superior to those using an Arrhenius model in the temperature zone above the assumed glassy-state transition. Research underway using ohmic heating of whiting surimi is showing that good gel strength was achieved when heating rates were very rapid (20-90(degree)C in 45 seconds). Data has been collected and modeled to give temperature- and ingredient-dependence of electrical and thermal conductivities and specific heat values. A description of the heat transfer model is in progress.

Impacts
(N/A)

Publications

• SIMPSON, R., E. KOLBE, G.A. MACDONALD, T.C. LANIER, M.T. MORRISSEY. Surimi production from partially processed and frozen Pacific whiting (Merluccius productus). In press, JI. of Food Science.
• HSU, C.K., E. KOLBE, M.T. MORRISSEY, Y.C. CHUNG. Protein denaturation of frozen Pacific whiting (Merluccius productus) fillets. JI. of Food Science, 58(5):1055-1056, 1075.
• WANG, D.Q. and E. KOLBE. Analysis of food block freezing using a PC-based finiteelement package. In press, JI. of Food Engineering.
• KITAGAWA, T., D.F. FARKAS, E. KOLBE. 1993. Effective high hydrostatic pressure on inactivation of polyphenoloxidase in pear. Presented at Food Preservation 2000, Natick Laboratories, October 1993.
• SIMPSON, R., E. KOLBE, G.A. MACDONALD, T.C. LANIER and M.T. MORRISSEY. 1993. Frozen stabilized mince as a source of Pacific whiting surimi. Proceedings of the Sixth International Congress on Engineering in Food; Chiba, Japan. Elsevier,.

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

Outputs
This describes the progress of E.Kolbe. A summary of J. McGuire's accomplishments and publications in included in AES Project 457. Research has shown that mince made from Pacific whiting and mixed with 6% sucrose can be made into good quality surimi after 6 months of storage at -20 /o.C. Total yields appear to be comparable to those expected in normal surimi processing operations. These results, coupled with quality modeling studies using whiting fillets and surimi, have played a significant role in management decisions to allocate 80,000 tons of the total allowable catch of 200,000 tons to shore-based processing operations. We also began a project with NC-136 colleagues to compare thermal analysis and property determination using Differential Scanning Calorimetry (DSC). Samples sent for analysis to 6 stations were cooking grease and a purified starch for transition parameters; glycerol and tylose for specific heat measurement. Preliminary results are currently being summarized.

Impacts
(N/A)

Publications

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

Outputs
Instrumentation to support torsion rheological tests has been set up at two of our laboratories (on campus and at the Coastal Marine Experiment station in Astoria). Research on the utilization of Pacific whiting for the manufacture of surimi is underway. A frozen mince stabilized with sucrose at -20 degrees C has been shown to be feasible for surimi manufacture. Frozen shelf-life studies of whiting fillets and surimi continue, with protein denaturation measures including rheological tests, salt soluble protein, ATPase activity. Changes are modeled with first order Arrhenius kinetics. We have completed study of Beta-lactoglobulin adsorption isotherms at a set of silicon surfaces varying in hydrophobicity, and Beta-lactoglobulin adsorption kinetics at each of these surfaces. Both protein arrival and unfolding kinetics are condidered. Behavior of three proteins, individual and in combination, were analyzed at air/water interfaces and at solid silicon surfaces at multiple temperatures and hydrophobicities. In spite of numerous chemical dissimilarities among these molecules, we met with success in relating their surface activity to molecular size, and issues related to stability and flexibility.

Impacts
(N/A)

Publications

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

Outputs
(Note that activities/progress of coinvestigator J. McGuire will appear in his Progress Report for Project 457.) A DuPont differential scanning calorimeter measured several temperature-dependent properties in frozen surimi under a range of cryoprotectant levels. The thermograms were first modified by a "dynamic correction" technique to better simulate static calorimetry. Properties which included bound water, enthalpy, apparent specific heat, and unfrozen moisture fraction were modeled by a modification of Schwartzburg's approach; results indicated good agreement with literature data such as that of Riedel. Measurements of freezing times in surimi blocks were simulated by a packaged finite element program (ANSYS) using time-dependent boundary conditions and the temperature-dependent property models previously derived. This work is currently in review for the Journal of Food Engineering. Preliminary results of protein denaturation in frozen Pacific rockfish indicated that DSC represents a possible means to monitor this change represented by enthalpy of transition. More work is needed to indicate the reliability and correlation with other measures. Product temperatures and freezer conditions were measured in a number of commercial seafood freezers in Alaska, indicating important influences on performance and potential quality loss.

Impacts
(N/A)

Publications

Progress 01/01/89 to 12/30/89

Outputs
Thermal conductivity of frozen pollock surimi was measured over a range of temperatures and concentrations of cryoprotectants. Data were well described by a thermal conductivity model of Schwartzburg as modified by Succar and Hayakawa. Results have been reviewed and accepted for publication. Three differential scanning calorimeter models were studied and evaluated before purchasing the DuPont system, using primarily University funds. The system which supports low temperature measurements is currently measuring apparent specific heat and bound water values of pollock surimi. Its application to research in Horticulture as well as in the food industry is also currently being explored. Measurement of temperatures in freezing surimi blocks was made in plate freezers at the National Marine Fisheries Service laboratories in Seattle and Kodiak. This data has correlated closely with a finite element computer model based on the ANSYS commercial program currently supported by the Department of Civil Engineering. Formulation of convection coefficients influenced by packaging materials, and development of an accurate specific heat model will further improve these correlations.

Impacts
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Publications

Progress 01/01/88 to 12/30/88

Outputs
Thermal properties. We have gained experience with measurement of thermal conductivities using small linear heat source probes monitored and controlled by a Campbell Scientific 21X datalogger. We have used a Perkin Elmer DSC-4 both to measure specific heat values for food samples, and to quantify gelation peaks which occur as surimi is heated through the range 40 to 90(degree) C. A proposal was submitted to NSF with coinvestigator L. Lampila (FST) for purchase of a new DSC in College of Ag. Sciences. Replicate values of thermal properties were measured for the glycerin sample distributed at the 1987 NC-136 meeting and reported to colleagues at Texas A&M. Refrigerated Seawater. Tests were conducted on a 1.3 m(superscript 3) tank representative of those used for chilling and holding fish aboard small vessels in the range 10-15 m. Flow conditions and evaporator configurations were evaluated for best fish chill rates. Energy consumed in surimi process. Documentation of energy consumed in at-sea preservation, in-plant processing, freezing, and cold storage was reviewed and applied to representative surimi processes having potential for Pacific Northwest plants.

Impacts
(N/A)

Publications