Source: WASHINGTON STATE UNIVERSITY submitted to
EXPLORING THE APPLICATION OF SOLID-STATE 915-MHZ MICROWAVE (MW) GENERATORS FOR COMMERCIAL PRODUCTION OF READY-TO-EAT MEALS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1030180
Grant No.
2023-67017-39831
Cumulative Award Amt.
$594,000.00
Proposal No.
2022-09203
Multistate No.
(N/A)
Project Start Date
Jun 1, 2023
Project End Date
May 31, 2027
Grant Year
2023
Program Code
[A1364]- Novel Foods and Innovative Manufacturing Technologies
Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001
Performing Department
(N/A)
Non Technical Summary
Microwave heating holds great potential in assisting the food industry and homes to save heating time and energy. But magnetrons that have been used to generate microwaves over the past 70 yrs have shortcomings, including limited service-life (~3,000 hours) and lack of precision control. The overall goal of this research is to overcome these limitations by exploring the application of state-of-the-art solid-state 915-MHz microwave generators in thermal processing of pre-packaged meals. Specific objectives are: 1) study the long-term stability performance of solid-state 915-MHz microwave generators; 2) develop a single-mode 915-MHz microwave test unit using solid-state generators for in-package heating; 3) study the effect of phase, frequency, and power ratio control from synchronized heads on heating uniformity and rate in packaged foods; and 4) integrate solid-state generators into a multi-cavity915-MHz microwave-assisted pasteurization system (MAPS) and use new microwave power control strategies to enhance system operation and overall performance for improved heating uniformity, increased heating rate, and better quality in a wide range of pre-packaged food products. The research will be conducted by a team of food and electrical engineers and a graduate student in collaboration with equipment companies. The outcomes will facilitate the use of solid-state microwave generators for precise control in commercial production of high-quality and safe pre-packaged foods. The project will help the USA to be the leader in application of advanced microwave technologies and contribute to reduction of energy use and environmental footprint of the food industry in transition towards a low-carbon or carbon neural modern industry.
Animal Health Component
35%
Research Effort Categories
Basic
30%
Applied
35%
Developmental
35%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
4025010202050%
7127299110020%
5015010208030%
Knowledge Area
712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins; 501 - New and Improved Food Processing Technologies; 402 - Engineering Systems and Equipment;

Subject Of Investigation
7299 - Research equipment and methods, general/other; 5010 - Food;

Field Of Science
2020 - Engineering; 1100 - Bacteriology; 2080 - Mathematics and computer sciences;
Goals / Objectives
The overall goal of this research is to overcome these limitations by exploring the application of state-of-the-art solid-state 915-MHz microwave generators in thermal processing of pre-packaged meals. Specific objectives are: 1) study the long-term stability performance of solid-state 915-MHz microwave generators; 2) develop a single-mode 915-MHz microwave test unit using solid-state generators for in-package heating; 3) study the effect of phase, frequency, and power ratio control from synchronized heads on heating uniformity and rate in packaged foods; and 4) integrate solid-state generators into a multi-cavity915-MHz microwave-assisted pasteurization system (MAPS) and use new microwave power control strategies to enhance system operation and overall performance for improved heating uniformity, increased heating rate, and better quality in a wide range of pre-packaged food products.
Project Methods
We willStudy long-term stability performance of 915 MHz SS MW generators through generator calibration, energy efficiency, and power, frequency & phase stability tests.Develop a single-mode 915 MHz MW heating test unit with one MW heating cavity powered by a SS MW generator with two launching heads.Study performance of 915 MHz MW heating using combined power from two synchronized SS generator heads with the newly developed 915 MHz SS MW heating unit, by investigating the effect of phase, frequency and power ratio on heating performance (uniformity, heating rate, and food quality) in packaged foods.Integrate SS MW units into a two-cavity MAPS system anduse new MW power control strategiesto enhance the overall system performancein terms of improved heating uniformity and heating rate for a wide range of pre-packaged food products.

Progress 06/01/23 to 05/31/24

Outputs
Target Audience:The food industry (particularly small and medium-sized food companies), food supply chain companies, microwave equipment companies, the research community, regulatory agencies, and the general public. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two research associates (Dr. Xu Zhou and Dr. Zhongwei Tang) are being trained in solid-state microwave system calibration and design and mathematical modeling. How have the results been disseminated to communities of interest?The results were submitted for presentation and were reported to the food science and engineering community at American Society of Agricultural and Biological Engineers (ASABE) AIM 2024 and 2024 Conference of Food Engineering (CoFE '24). Zhou, X., Tang, Z., Lin, H., Pedrow, P., Tang, J. Developing a computer simulation model for a solid-state powered MAPS (Microwave-Assisted Pasteurization System), Poster presentation, ASABE Annual Meeting, Anaheim, CA, USA, July2024. Zhou, X., Tang, J. Why solid-state microwave generators are the future of microwave heating. Oral Presentation, 2024 Conference of Food Engineering, Seattle, WA, USA, August 2024. What do you plan to do during the next reporting period to accomplish the goals?Next year, we plan to: 1) study factors influencing energy coupling in the developed solid-state powered single-mode microwave cavity and develop strategies to improve energy efficiency; 2) investigate the effect of phase, frequency, and power ratio on heating uniformity, heating rate, and food quality.

Impacts
What was accomplished under these goals? 1. Stability study of solid-state microwave generator We utilized a water calibration load to evaluate the stability and reliability of the solid-state generator, including power, frequency, and phase, in September 2023 and compared the results with preliminary tests from April 2021. Between these two test dates, the solid-state generator was used occasionally. The results from these tests were highly repeatable; all solid-state microwave parameters, including forward power, reflected power, and operating frequency, remained consistent. This demonstrates that the solid-state generators have excellent performance stability over the tested two-year period. We will continue to collect data on the stability and reliability of the solid-state generators after they are installed in MAPS and under normal food processing conditions. Additionally, the measured frequency and output power matched the settings of the solid-state generator within a 0.1% difference, indicating high accuracy in frequency and power control. 2. Development of computer simulation model for solid-state powered microwave cavity A three-dimensional computer simulation model was developed to solve Maxwell's and heat transfer equations using QuickWave 2020 (QWED, Warsaw, Poland). This model helps understand microwave fields in waveguides and cavities under different solid-state microwave settings, including phase, frequency, and power. The model is also used to predict heating patterns in pre-packed model food (mashed potato with Gellan gel). The simulation revealed that food heating patterns and energy coupling between the cavity and the generator are significantly influenced by solid-state microwave parameters, particularly phase differences. The model will be used to improve the microwave cavity design and optimize microwave pasteurization processes. 3. Development of a single-mode 915 MHz microwave heating test unit with one cavity powered by two synchronized solid-state generator heads The solid-state powered microwave heating cavity was developed and integrated into an existing pilot-scale Microwave-Assisted Pasteurization System (MAPS) at Washington State University. The 915 MHz solid-state microwave generator can synchronize microwave power and control the phase difference between its two output ports connected to the applicator cavity. Each generator head is remotely controlled and monitored for various experimental settings. Experiments using gellan gum model food trays with M-2 chemical marker precursors were conducted with the developed microwave cavity. The experimental results matched the simulation results and validated our simulation model.

Publications

  • Type: Book Chapters Status: Awaiting Publication Year Published: 2024 Citation: Zhou, X., & Tang, J. (2024). Microwave-assisted pasteurization and sterilization. In A. Sing, S. Wang, F. Erdogdu, & H. Ramaswamy (Eds.), Microwave processing of foods: Challenges, advances and prospects. Springer.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Zhou, X., Tang, Z., Lin, H., Pedrow, P., & Tang, J. (2024). Developing a computer simulation model for a solid-state powered MAPS (Microwave-Assisted Pasteurization System) [Poster presentation]. ASABE Annual Meeting, Anaheim, CA, USA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Zhou, X., & Tang, J. (2024). Why solid-state microwave generators are the future of microwave heating [Oral presentation]. 2024 Conference of Food Engineering, Seattle, WA, USA.