Progress 09/01/09 to 08/31/13
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
1. Novel dual cylindrical microwave chambers equipped with an ohmic heating tube were designed and fabricated to maximize the electric field strength for uniform heat treatment of particulate foods. Designing of the combination chamber was optimized and validated using the numerical simulation for electric field and potential distributions. Thermal profiles of solid-liquid mixtures consisting of sodium chloride solution (0.5 ~ 2% concentration), chicken, and potato particulates at different mass fractions (10 and 15%) were collected and compared for individual and combination heating modes when the exit temperature of either solid or liquid phase reached approximately 80°C in 36 sec. Results indicated that particle size (0.5 and 1 cm in length) and salt concentration substantially affected temperature variations between solution and particulates in ohmic heating. On the other hand, for microwave heating the solution temperature always lagged behind the particle temperature with salt concentrations up to 1.25%, regardless of particle size and mass fraction; however, an opposite pattern was observed in the food mixtures including 2% salt concentration. The maximum temperature differences between solid and liquid phases obtained by individual microwave and ohmic heating were 7.1 ± 1.7 and 11.9 ± 2.9 °C, respectively; while the combination heating exhibited no significant temperature gaps (maximum temperature difference < 3.08°C) at low salt concentrations (up to 1.25%). The controllable ranges of key variables to permit heating uniformity in the developed heater were obtained using the factorial analysis and response optimzer. 2. A numerical model using COMSOL codes was developed to validate uniform heating of particulate foods in a continuous flow microwave (MW) and ohmic (OH) combination heating chamber. The developed model was integrated with microwave heating, ohmic heating, incompressible laminar flow, forced-coupling method (FCM), heat transfer and arbitrary Langrangian-Eulerian (ALE) moving mesh technique. The solid particles were simulated to experience hydrodynamic viscous drag and pressure forces resulting from motion relative to the fluid. The stress tensors of forces exerted on the surfaces of the particles were successfully formulated by use of the FCM module. The large deformation and movement of geometric mish containing trajectories of particles inside the feeding tube were successfully executed in the state of the transient mode. The outlet temperatures of particulate foods under microwave, ohmic and combination heating also were in a good agreement with experimental data within the error of 4%.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Abdullah, S., Lee, S.H., Cho, I., Choi, W., and Jun, S. 2013. Pasteurization of Kava Juice using Novel Continuous Flow Microwave Heating Technique. Food Science and Biotechnology 22(4): 961-966
- Type:
Journal Articles
Status:
Under Review
Year Published:
2013
Citation:
Lee, S.H., Choi, W., Yoon, S.K., and Jun, S. 2013. Development of a dual cylindrical microwave and ohmic combination heater for minimization of thermal lags in the processing of particulate foods. Innovative Food Science and Emerging Technologies
- Type:
Journal Articles
Status:
Submitted
Year Published:
2013
Citation:
Choi, W., Lee, S.H., and Jun, S. 2013. Numerical Approach of a Continuous Flow Microwave and Ohmic Heating for Particulate Foods using a Finite Element Method. Transactions of the ASABE
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Nguyen, L.T., Choi W., Lee, S.H., Jun, S. 2013. Exploring the Heating Patterns of Multiphase Foods in a Continuous Flow, Simultaneous Microwave and Ohmic Combination Heater. Journal of Food Engineering 116(1): 65-71
- Type:
Journal Articles
Status:
Submitted
Year Published:
2013
Citation:
Lee, S.H. and Jun, S. 2013. Current and Emerging Combination Technologies for Food Processing: A Review. Food and Bioprocess Technology
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Jun, S. 2013. Continuous Flow, Simultaneous Microwave and Ohmic Combination Heating Technology for Multiphase Foods. The 2013 IFT Annual Meeting, July 14-16, Chicago, IL (268-04)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Lee, S.H., Choi, W., and Jun, S. 2013. Continuous Flow, Simultaneous Microwave, and Ohmic Combination Heating Technology for Multiphase foods: Simulation for Thermal Uniformity and Lethal Effectiveness. The 2013 IFT Annual Meeting, July 14-16, Chicago, IL (031-21)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Choi, W., Lee, S.H., and Jun, S. 2013. Application of an ohmic thawing unit combined with a microwave heater. The 2013 IFT Annual Meeting, July 14-16, Chicago, IL (031-18)
- Type:
Journal Articles
Status:
Submitted
Year Published:
2013
Citation:
Abdullah, S., Choi, W., and Jun, S. 2013. Mathematical Modeling and Numerical Simulation for Predictive Retention of Antioxidant Activity of Grape Juice Pasteurized with Continuous Flow Ohmic Heating. International Journal of Agricultural and Biological Engineering
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: The design of the combination heater was optimized by non-destructive numerical analysis. Teflon tube with a pair of ring-shaped electrodes housed inside both ends was installed at the middle of dual cylindrical microwave cavities. The combination heater was evaluated using food mixtures consisting of potato and chicken cubes (about 1 cm^3), and carboxymethylcellulose (CMC) solution. The maximum temperature differences found in solid-liquid mixture under individual microwave and ohmic heating were approximately 8.1 and 8.0 degC, respectively. Temperature difference exists even between various solid particles during ohmic heating rather than microwave heating. However, when microwave and ohmic heating was simultaneously applied, there was little significant temperature difference between solid particles and liquid phases (less than 2 degC). The energy efficiency of ohmic and microwave heating were 94.2 and 55.4%, respectively. However, the hybrid combination heating increased energy conversion efficiency by 24.7% as compared to microwave heating. Two papers have been accepted and three talks were given at the conference meetings at Japan and Chicago, IL. Nguyen, L.T., Choi W., Lee, S.H., Jun, S. 2012. Exploring Heating Patterns of Multiphase Foods in a Continuous Flow, Simultaneous Microwave and Ohmic Combination Heater. Journal of Food Engineering (Accepted) Abdullah, S., Lee, S.H., Cho, I., Choi, W., and Jun, S. 2012. Pasteurization of Kava Juice using Novel Continuous Flow Microwave Heating Technique. Food Science and Biotechnology (Accepted) Nguyen, L.T.,Choi, W., Lee, S.H. and Jun, S. 2012. Exploring the Heating Patterns of Multiphase Foods using Continuous Flow, Simultaneous Microwave and Ohmic Combination Heating Technique. FOOMA JAPAN 2012: International Food Machinery and Technology Exhibition. Abdullah, S., Choi, W., and Jun, S. 2012. Simulation of Antioxidants Activity of Grape Juice with Continuous Flow Ohmic Heating, The 2012 IFT Annual Meeting, June 26-28, Las Vegas, NV (077-01) Lee, S.H., Choi, W., Nguyen, L., and Jun, S. 2012. Continuous Flow, Simultaneous Microwave, and Ohmic Combination Heating Technology for Thermal Uniformity of Multiphase Foods, The 2012 IFT Annual Meeting, June 26-28, Las Vegas, NV (077-16) PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Food beverage companies to heat process meat vegetable soups and chunky mixed fruit juice. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The findings will open new and very promising opportunities to thermally process particulate foods (i.e. meat vegetable soup and chunky mixed fruit juice) with improved uniformity, organoleptic, nutritional quality and reduced food safety problems.
Publications
- No publications reported this period
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: Based on the preliminary data obtained from the experiment conducted at the first year of this project, a continuous flow, simultaneous microwave and ohmic combination heater was designed and fabricated. The project in Year 2 was intended to explore and compare the heating patterns of particle-liquid mixtures under individual heating (microwave and ohmic heating) and the combination heating. A pair of ring-shaped electrodes made of titanium was inserted into both ends of Teflon pipe for ohmic heating and the pipe was vertically installed at the center of microwave cavity for simultaneous microwave and ohmic combination heating. Prior to the temperature measurement of the particle-liquid mixture (carrot cubes and carboxymethylcellulose (CMC) solution) treated using the combination heating technology, the electric field and temperature distribution of the food mixture inside the cavity were simulated using a commercial finite element methods (FEM) software (COMSOL 3.4, COMSOL, Inc., Palo Alto, CA). Single heat treatments showed opposite results; carrot particles were heated faster than CMC solution by 8.1 degC under microwave heating and however, CMC solution was heated up faster than solid particles by 8 degC when ohmic current was applied. Uniform heating was achieved under simultaneous combination heating and the temperature difference between particles and CMC solution was only 0.5 degC. The experimental data was in good agreement with simulation data. Hybrid combination heating also increased the energy efficiency by 10.6%, as compared to microwave heating. Power control of both heating methods and combination logic in terms of the frequency and wave characteristics will be intensively researched in the next phase of this project. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The result from this study clearly showed that uniform heating pattern of solid-liquid food mixtures is achievable in a continuous mode when the combination heating technology was applied. This is critical because under-processed solid particles are always at risk in terms of food safety. The pretreatment process such as salt infusion can be removed from the line once the developed technology is accepted for commercial food processing. Combined ohmic and microwave heating technology can significantly contribute to energy savings. This technology will compensate for the safety level of the microbial lethality in particulate food products and will be effectively applied for sterilization processing of low acid multiphase foods containing large particulates as well.
Publications
- Lee, S.H., Nguyen, L.T., Choi, W., & Jun, S. (2011). Exploring the heating patterns of multiphase foods in a continuous flow, simultaneous microwave and ohmic combination heater. The 23rd Annual CTAHR Students Symposium, Honolulu, HI.
- Jun, S. (2011). Exploring the heating patterns of multiphase foods in a continuous flow, simultaneous microwave and ohmic combination heater. ICEF Annual Meeting, Athens, Greece.
- Nguyen, L.T., Choi, W., Lee, S.H., Jun, S. (2011). Exploring the heating patterns of multiphase foods in a continuous flow, simultaneous microwave, and ohmic combination heater. IFT Annual Meeting & Food Expo, New Orleans, LA.
- Choi, W., Nguyen, L.T., Lee, S.H., and Jun, S. (2011). A microwave and ohmic combination heater for uniform heating of a liquid-particle food mixture. Journal of Food Science,76, E576 - E585
- 61/488,107, Continuous flow microwave and ohmic combination heating technique for multiphase foods. Provisional patent application filed on May 19, 2011.
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: In the first year of the project, the concept of combined heating techniques was explored in a small scale experimental setup including a static test cell. Before a continuous flow microwave and ohmic combination heater can be made, a simple, custom made static heater could be helpful to gain insights into the heating patterns of the liquid-particle mixtures. Simple food models composed of vegetable particulates (1cm cubes) and sodium chloride solution were used in the study. The viscosity of liquid sample was adjusted using carboxymethylcellulose (CMC) so the particulates can be suspended in the solution. This property is important as the particulates will be pumped through the continuous flow heater in the next phase of the study. To better understand the heating uniformity of the multiphase mixtures, temperature distribution was investigated by numerical simulation with the aid of a commercial FEM software (COMSOL 3.4, COMSOL, Inc., Palo Alto, CA) and was validated with experimental data. Extensive data of electrical and dielectric properties of foods as a function of temperature were also experimentally determined. Under studied conditions, experimental data showed that liquid temperature was uniform during ohmic heating as compared to microwave heating. However, for a continuous flow heater, the mixing of liquid will enhance the temperature uniformity and only the average liquid temperature is critical in this case. Solid particle, after 2 min of microwave heating, was heated faster than liquid about 13.0 degree Celsius. For ohmic heating, liquid was heated faster than solid and the thermal gradient was about 21.0 degree Celsius. When two heating modes were combined, temperature of solid particles ended up close to that of the liquid, leading to a more uniform temperature throughout the product. The obtained simulation results showed similar trends and had a good agreement with experimental data. Works under progress included design and fabrication of the continuous flow, sequential microwave and ohmic combination heater. The developed device will help confirm the concept in the continuous flow mode that is more realistic for practical applications. The heater development involved design, optimization of energy conversion and electric field distribution. Simulation for continuous flow combination heating had been conducted and still under progress. The results will be reported in the next phase of the study. PARTICIPANTS: Dr. Loc Nguyen Junior Researcher Department of Human Nutrition, Food and Animal Sciences University of Hawai`i at Manoa 1955 East-West Road Honolulu, HI 96822-2321 Tel: + 808 -956-6588 e-mail: loc749@hawaii.edu TARGET AUDIENCES: Food industries: Development of a continuous flow microwave and ohmic combination heater would provide a new insight for food sterilization in food industries. Continuous flow processes of particulate foods are hampered by FDA concerns over the residence time distributions. If a product containing food particulates can be heated rapidly and uniformly, a significant quality improvement may be expected and the process of FDA approval should be easier. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The findings during the initial stage of this study clearly demonstrated that a product containing food particulates can be heated rapidly and uniformly by combined microwave and ohmic heating. Liquid was heated faster by ohmic current and solids were heated by microwave, independent of their electrical conductivity. Unlike conventional thermal processing, ohmic or mircrowave heating, the combined heating eliminates the downsides of the individual heating technologies. Given this data, we believe that the development of a microwave and ohmic combination heater could provide new options for food sterilization and provides a promising opportunity to improve both the safety and quality of processed foods.
Publications
- Nguyen, L.T., Choi, W., Lee, S.H., Jun, S. Exploring the Uniformity in Thermal Patterns of Multiphase Foods Using the Novel Microwave and Ohmic Combination Heating Technology. 2010 IFT Annual Meeting, Chicago, IL.
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