Progress 08/15/03 to 08/14/08
Outputs
OUTPUTS: Five outputs were generated from this research: teaching, conference presentations, press releases, demonstrations, and a patent. New knowledge in the understanding of immersion frying heat transfer, infrared heating, and process development were taught in the classroom at both the undergraduate and graduate levels. At the undergraduate level, discussion of convection and boiling heat transfer during immersion frying was used both in the context of teaching fundamental principles of heat transfer as well as with focus on the unit operation of frying. Process development was taught via the "ideation, discovery, and development" of a new heating process which replicates immersion frying but uses radiant heating. This mental "invention" allowed the students to see the process of research, design, and development for a new process. At the graduate level concepts in radiant heat transfer and process design and mathematical modeling were taught using the data and results generated by this research. Over the course of the research papers were presented at conferences hosted by the Institute of Food Technologists, American Institute of Chemical Engineers, EuroFed Lipid, and International Congress on Engineering and Food. In all, six papers were presented on various aspects of this research. Topics covered included infrared emitter spectral characterization, mathematical modeling of radiant heat transfer, design of an infrared finish fryer, and instrumental and sensorial comparison of immersion fried and infrared finish fried products. Several press releases have been put out by Purdue University in the late summer and fall of 2008. These releases have covered the development of the patented infrared finish fryer developed by research conducted under this grant. Over the past four years we have demonstrated the infrared finish fryer to a number of company officials. These officials represent the food service/fast food industry, snack food industry, breakfast foods industry, frozen food industry, and custom machine fabrication industry. In addition to demonstrating the system to interested companies, we have given a number of demonstrations to K-12 classes in the area. The focus was on science and the use of engineering to develop new technology for production of healthy foods. Lastly, this research resulted in US patent #7,307,243, Dynamic Radiant Food Preparation Methods and Systems. PARTICIPANTS: PI Farkas, B.E.: Developed original concept of using infrared heating to duplicate the immersion frying processes. Directed the development of the prototype oven used in the research. Mentored the doctoral student associated with the project. Co-authored presentations, journal papers, and a patent. Co-PI Keener, K.M.: Mentored the doctoral student associated with the project, contributed to the development of the prototype oven, and moved the technology to the commercial sector. Co-authored presentations, journal papers, and a patent. Doctoral student Lloyd, B.J.: Conducted basic research in infrared emitter technology, designed and constructed the prototype infrared oven. Co-authored presentations, journal papers, and a patent. Research technician Reinitz, H.: Developed control system for continuously changing the power of a single emitter or pair of emitters such that it/they follow a prescribed heat flux curve. This allowed testing of various heating profiles in producing fried-like products. TARGET AUDIENCES: The target audience for this research was individual research scientists actively involved in process engineering of frying and alternative frying methods. Additionally, the resultant patent was targeted at corporations engaged in production of fried or fried-like foods, or machinery capable of producing such products. Efforts resulting from this research included classroom instruction at the undergraduate and graduate levels. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This research lead to a change in conditions vis-a-vis improved nutrition and health through development of a method to produced fried foods with a 30-70% reduction in oil content. The process uses continuous dynamic radiant heating of par-fried foods to produce a finish fried product. It is well known that as a food is fried is picks up increasing amounts of oil. Foods fried for a short period of time have low amounts of oil thus a partial fry, or par-fry, is used to establish a crust matrix and add the low but necessary coating of oil. These low oil containing foods are then finished fried using the infrared oven without further addition of oil. The result is a reduced fat fried product.
Publications
- Farkas, B.E., Lloyd, B.J., and Keener, K.M. 2004. Development of a Radiant Heating Process to Mimic Immersion Frying. Abstract 251. 9th International Congress on Engineering and Food. Montpellier, France, March 7-11.
- Lloyd, B.J., Farkas, B.E., and Keener, K.M. 2003. Mathematical Modeling of Radiant Heating of Foods. Session T9002, Abstract, Conference on Food Engineering, American Institute of Chemical Engineers Annual Meeting, November 16 - 22, San Francisco, CA
- Lloyd, B.J., Farkas, B.E., and Keener, K.M. 2003. Characterization of radiant energy sources used for food processing. Paper 29D-5, Abstract. National IFT Annual Meeting, Chicago, IL, USA, July 12-16.
- Lloyd, B.J., Farkas, B.E. and Keener, K.M. 2004. Quality comparison of French fry style potatoes produced by oven heating, immersion frying, and controlled dynamic radiant (CDR) heating. Journal of Food Processing and Preservation, (28) 460-472.
- Lloyd, B.J., Farkas, B.E. and Keener, K.M. 2004. Characterization of Radiant Emitters used in Food Processing. Int. J. of Microwave Power and Electromagnetic Energy, 38(4).
- Farkas, B.E., Lloyd, B.J., and Keener, K.M. 2004. Development of a Radiant Heating Process to Mimic Immersion Frying. Refereed Proceedings of the 9th International Congress on Engineering and Food. Montpellier, France, March 7 -11.
- Yaniv, Y.R., Farkas, B.E., Keener, K.M. 2007. Mathematical modeling of high intensity infrared heating of a food matrix. Paper 141-11, Abstract. National IFT Annual Meeting, Chicago, IL, USA, July 28-August 1.
- Farkas, B.E., Yaniv, Y.R., and Keener, K.M. 2005. Development of an Alternative Finish Frying Process. 5th International Symposium on Deep Frying, San Francisco, CA, February 20-22, 2005
- Farkas, B.E., Lloyd, B.J., and Keener, K.M. 2004. Numerical Simulation of a Radiant Finish Frying Process. Paper 111-9, Abstract. National IFT Annual Meeting, Las Vegas, NV, USA, July 12-16.
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Progress 10/01/06 to 09/30/07
Outputs
Immersion frying is one of the most widely used fundamental unit operations in food processing. Frying produces foods of unique and characteristic properties such as a golden color, crisp crust, tender moist core (for non chip items), and an appealing flavor. However, frying has the distinct disadvantages of creating a high caloric content food, and it lacks in process control for oil uptake. In batch frying operations, such as that used by the food service industry, disadvantages include: cost of frying oil, disposal of used oil, little control of oil content in finished product, and the creation of a dangerous work environment known to cause severe burns of workers. An alternative process for immersion finish frying which addresses the disadvantages outlined above, is proposed. It is hypothesized that controlled radiant heating may be used to duplicate the dynamic and intense heat flux described in earlier studies. The heat flux profile was found central in
developing the unique fried food characteristics. This hypothesis is based on the investigators' fundamental understanding of the heat and mass transfer which occurs during immersion frying and was successfully tested and is described in the Preliminary Research section. Preliminary study has shown on a qualitative level the feasibility of a radiant finish frying process. The proposed research seeks to develop a quantitative understanding of how radiant heat transfer interacts with food materials during finish frying to produce fried-like products. The relationship between radiant emitter properties (spectral wavelength distribution and power intensity) and product properties, such as crust formation, surface browning, and heating rate, will be determined. The goal of the proposed research is to develop a fundamental understanding of the relationship between a dynamic, intense radiant heat flux and the food surface which it is incident upon. This research will benefit the fried foods
industry by collecting and analyzing basic data necessary for new process development of an alternative finish frying process. In parallel with continued testing of the controlled dynamic radiant (CDR) oven prototype, design of an "instrument grade" oven was started. The current prototype is a continuous system with stationary emitters of fixed intensity and wavelength. As the food travels through the oven, it is exposed to the desired heat flux profile via exposure to the emitters it passes between. This approach works for pilot scale testing but it is difficult to change emitter position for optimization and testing of the oven design. The new oven will operate in a batch mode with the emitter position and infrared flux and wavelength being controlled by a computer. This approach will allow rapid, accurate, and precise control of all oven design characteristics.
Impacts
The use of high intensity, controlled flux infrared heating as an alternative to immersion frying has potential to produce fried-like products with greatly reduced oil and caloric content.
Publications
- Farkas, B.E., Lloyd, B.J. and Keener, K.M. 2007. Dynamic Radiant Food Preparation Methods and Systems. United States Patent 7307243.
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