Progress 09/01/13 to 08/31/18
Outputs
Target Audience:The target audience for this year's work is both the academic community and the food industry. Wepresented results in IFT conference and Conference of Food Engineering and received useful feedback from people in USDA,universities and private sector. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training: two PhD students from Washington State University came to our lab in 2016 summer for one month. They learnt validation methods with RF pasteurization and conducted collaborative research. 5 undergradute students in FDST 4400 courses (Senior Project Design) participated in the project and learnt the basic principle and operation of RF oven. 9 graduate students in FDST8060 course (Advanced Food Processes) learnt methods of dielectric property measurement and heating rate/uniformity determination with RF heating. Professional development: two seminars (40 min) in RF heating were given in UGA food science department and TianJin university. How have the results been disseminated to communities of interest?One symposium was offered in IFT meeting 2017 in low moisture food pasteurization focusing on RF heating. In addition, there were about 10 oral/poster presentations offered in different conferences inclduing IFT conference, Conference of Food Engineering, IuFOST, etc. Five papers were published in professional peer-review journals. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Low-moisture foods/ingredients, with water activity (aw) level less than 0.7, are commonly used for various applications in food industry. In the last decade, Salmonella contaminated low-moisture foods, including powdered vegetables and infant formula, dry fruit and nuts, spices etc., have become a major safety concern. Outbreak of Salmonella was reported in broccoli powder, pepper, starch, chilli powder and peanut butter. The high heat resistance of Salmonella in low-moisture foods makes pasteurization of dried foods a difficult task. The conventional pasteurization methods such as steam and hot air heating require long processing times due to the slow heating rate, leading to severe quality degradation. Radio Frequency (RF) heating is a volumetric heating which is more rapid than conventional heating, requiring less process time that can result in improved final product quality and reduced treatment cost. In this project, effectof RF heating on food pasteurization, including broccoli powder, seasoning spices and corn starch, was investigated. The protocol of RF pasteurization and validation were explored as well as different ways to improve heating uniformity, a critical challenge to application of RF pasteurization in dehydrated food powders. The results indicated that RF heating is effective in pasteurizing food powders with shorter time leading to better food quality as compared to conventional heat treatment. The study provided evidence and guidelines for using RF heating as an alternative pasteurization technology in low moisture foods. Specifically, we measured dielectric properties of selected dried vegetables and spices. Dielectric properties of white/red pepper, chilli powder, onion powder, corn starch, broccoli powder, milk powder, egg powder, and other seasoning spices were determined as affected by moisture (2-12%), temperature (20-90 degree C), frequency (up to 30 MHz) and their mixing ratio. This information iscritical to estimatethe heating rate and penetration depth when they are subjected to RF heating. Overall, the dielectric constant and loss factors are low due to the low moisture content, and decreased with frequency and increased with temperature. We then investigatedheating rates and uniformity of RF heating as affected by various processing parameters (electrode gap, package size and shape). Selected food powders including corn starch, spices, milk powder, egg powder were heated in a 27 MHz, 6 kW RF oven, and the heating rates were determined by fiber optic sensor. The heating uniformity was studied using an infrared camera and a custom made PEI box attached with 15 thermocouples. The results indicated that edge and corner heating occurred on food powders. Heating rate has an inverse relationship with uniformity, i.e. faster heating led to less uniform heating. Heating rates are greatly affectly by the dielectric loss factor, the gap of electrodes, the size and the dimensional configuration of the food package. We further developed methods to improve heating uniformity. We foundthat some materials, when wrapped around food samples, resulted in better uniformity. Also, slower heating rate can help heat penetration/conduction to obtain higher uniformity. Furthermore, we carried out kinetic study to determine thermal resistance of Salmonella in selected foods. The thermal resistance of salmonella and the surrogate including D value and Z value were determined when they are presented in different food matrix (white/red peppers andcorn starch). The results indicated a stronger resistance of pathogen/surrogate in low moisture environmentas compared to high humidity environment. Using the D and Z values, we validated the lethality of pathogen afterRF heating. Protocols were proposed to validate RF heating process that could be used in food industry. At last, we studied the effect of combination of RF and cold shock (freezing) in enhancing the inactivation effect of Salmonella. The results showed a significant improvement (1-2 log reduction) after cold shock treatment. Therefore, commbination of RF and cold shock treatment can be a promising technology to be used in food industry.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Ozturk S, Kong F, Singh RK, Kuzy JD, Li C. 2018. Dielectric properties, heating rate and heating uniformity of various seasoning spices and their mixtures with radio frequency heating. Journal of Food Engineering. 228:128-41.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Xu, J., Liu, S., Tang, J., Ozturk, S., Kong, F. and Shah, D.H., 2018. Application of freeze-dried Enterococcus faecium NRRL B-2354 in radio-frequency pasteurization of wheat flour. LWT, 90, pp.124-131.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Kong F. Radio Frequency Heating of Food Powders and the Influencing Factors. 2018 Conference of Food Engineering (COFE). September 10-12, Minneapolis, MN. (Oral presentation)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Ozturk S., Kong F., Singh R. Inactivation of Salmonella and E. Faecium NRRL B-2354 With Radio Frequency Heating in Packaged Paprika, White Pepper, and Cumin Powder. 2018 IFT meeting, July 16-18. Chicago IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Lee N., Kong F. The Effects of Package Size and Electrode Gap on Heating Rate and Uniformity During Radio Frequency Heating of Low Moisture Foods. 2018 IFT meeting, July 16-18. Chicago IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Damla D., Kong F. Temperature and Frequency Dependent Dielectric Properties and Radio-Frequency Heating of Whole Milk Powder, Non-Fat Milk Powder, and Their Mixtures. 2018 IFT meeting, July 16-18. Chicago IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Samet Ozturk, Fanbin Kong. 2015. Dielectric properties and heating rate of broccoli powder as related to radio frequency heating. IMPIs 49th Microwave Power Symposium. June 16-18, 2015. San Diego, California. (Poster presentation)
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2018
Citation:
Ozturk, S. (2018). Pasteurization of dehydrated food powders with radio frequency heating ((Doctoral dissertation). Retrieved from: http://dbs.galib.uga.edu/cgi-bin/getd.cgi?userid=galileo&serverno=23&instcode=uga1&_cc=1
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2018
Citation:
Lee B.N. (2018) Radio frequency heating of low moisture food: influences of package dimension and electrode gap, application on egg powders (Master thesis). Retieved from: http://dbs.galib.uga.edu/cgi-bin/getd.cgi?userid=galileo&serverno=23&instcode=uga1&_cc=1
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Progress 09/01/16 to 08/31/17
Outputs
Target Audience:I organized a session in the 2017 IF annual conference titled "Recent developments in pasteurization of low-moisture foods" and gave a presentationtitled "Radio-frency pasteurization of dried food powders" PhD student Samet made an oral presentation in 2017 IAFP conference titled "Inactivation of Salmonella in Corn Flour by Radio Frequency Heating and the Effect of Cold Shock" A poster presentation was made inUSDA NIFA Project Director (PD) Meeting, and 2016 IFT meeting. One paper was published in peer review journal and another was accepted. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project was incorporated into an undergraduate course FDST 4400 Senior Project design to teach students RF heating for food pasteurization. 4 students worked on the project to design a RF pasteurization process for dried spices. Through the course they learnt principles and operations of RF equipment, and understood the effect of different processing parameters on heating. In addition, RF heating demonstration were incorpoarted into a graduate level course "Advanced Food Processes", 8 master& PhD students operated the RF equipment and learnt hands on expeicence of the technology. How have the results been disseminated to communities of interest?Two papers were published/accepted in peer-revieew journals. Two oral presentationswere made in professional conferences. A symposium session was organized in 2017 IFT meeting in RF pasteurization of dried food powders. What do you plan to do during the next reporting period to accomplish the goals?In the next year, we will work on validation of the RF pasteurization ofsamonella and its surrogate in corn flour and various spices. We will also investigate cold shock effect in conmbination of RF heating.
Impacts
What was accomplished under these goals?
We have evaluated the effect of different electrode gaps, moisture content (MC), bulk density and surrounding materials on RF heating uniformity and rate in corn flour. Additionally, the dielectric and thermal properties of corn flour were determined as affected by MC, temperature (°C), and frequency (MHz). Changes in MC, water activity (aw) and color in the sample after RF heating were measured to evaluate treatment effect on food quality. A precision LCR meter and a liquid test fixture were used to study DP of the sample at RF frequency ranging from 1 to 30 MHz. The RF heating uniformity and temperature profiles of corn flour as exposed to RF heating were obtained with an infrared camera and data logger using a fiber optic sensor. The DP values increased with increasing MC and temperature, but decreased with increasing frequency. The heating rate increased from 3.5 to 6.8 °C min-1 with increasing MC (from 10.4 to 16.7%), but decreased from 12.7 to 5.2 °C min-1 with increasing electron gap (from 11 to 15 cm). The corner and edge heating was observed at all layers of the samples for all the distances, and the hottest and the most uniform layer were determined as middle layer at an electrode gap of 15 cm. Glass petri dish provided better uniformity than those of polyester plastic petri dish. Covering by foam led to more uniform RF heating uniformity in corn flour, and better moisture and aw distribution. This study provided useful information to develop an effective RF process as an alternative of conventional thermal treatments for pasteurization of low-moisture products. In another study collaborated with Dr. Juming Tang at Washington State University, we developeda microbial validation method for radio frequency (RF) pasteurization of low-moisture food powders. Wheat flour with water activity of 0.45±0.02 was used as a model. In this study, heat resistance parameters (D- and z-values) ofSalmonellaEnteritidis PT 30 (S.Enteritidis) and its potential surrogateEnterococcus faeciumNRRL B-2354 (E.faecium) in wheat flour were determined. The results showed that, while both microorganisms yielded the similar z-values,E.faeciumwas more heat-resistant thanS.Enteritidis. For process validation, a 5-g pack of wheat flour inoculated with either microorganism was placed in the geometric center of 3kg wheat flour and subjected to various processing times of up to 39min in a 27MHz RF unit. The inactivation kinetics matched but yielded slightly greater reduction than pasteurization modeled from measured temperature profiles and microbial thermal resistance parameters. This investigation concluded thatE.faeciumis a valid surrogate forSalmonellain wheat flour. A conservative validation can be obtained by inoculated pack protocol. RF heating technology has potential for pasteurizing wheat flour.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Ozturk S, Kong F, Singh RK*, Kuzy JD, Li C. 2017. Radio frequency heating of corn flour: Heating rate and uniformity. Innovative Food Science & Emerging Technologies. 44(12)191-201.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2018
Citation:
Liu S, Ozturk S, Xu J, Kong F, Gray P, Zhu MJ, Sablani SS, Tang J. 2018. Microbial validation of radio frequency pasteurization of wheat flour by inoculated pack studies. Journal of Food Engineering. 2018 Jan 1;217:68-74.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Ozturk S, Kong F, Singh R, Liu S, Tang J. Inactivation of Salmonella in Corn Flour by Radio Frequency Heating and the Effect of Cold Shock. IAFP 2017. July 8-12. Tampa, Florida.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Kong F. 2017. Radio frequency pasteurization of dried food powders. . June 26. 2017 IFT meeting. Las Vegas. NV.
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Progress 09/01/15 to 08/31/16
Outputs
Target Audience:Oral/poster presentations were made in theIUFoST 2016Dublin -the 18th World Congress of Food Science and Technology, USDA NIFA Project Director (PD) Meeting, and 2016 IFT meeting. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?One PhD student has made oral presentation in IFT meeting. Two PhD students from Washington State University joined our lab in summer, 2016,and conducted one month collaborative research in RF pasteurization of wheat flour. How have the results been disseminated to communities of interest?Oral/poster presentations were made in IFT meeting, IuFost meeting, and other conferences. What do you plan to do during the next reporting period to accomplish the goals?Thermal resistance of Salmonella inoculated in corn flour/spicesand the effect ofRF pasteurization will be studied.
Impacts
What was accomplished under these goals?
The dielectric properties (DP) of corn flour and spices were also determined as affected by moisture content (MC), temperature (°C), and frequency (MHz). The heating uniformity and temperature profiles of corn flour as exposed to RF heating were obtained with an infrared camera and a fiber optic sensor. The effect of different electrode gaps, and surrounding materials were investigated. Changes in MC, aw and color in the samples after RF heating were measured to evaluate treatment effect on food quality.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Ozturk S., Kong., Singh R. (2016). Heating uniformity in corn flour exposed to radio frequency treatment. 18th World Congress on Food Science and Technology (IUFoST). August 21 25, 2016. Dublin, Ireland
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Ozturk S., Kong., Singh R. Dielectric properties of seasoning spices and their heating rates during radio frequency. 2016 IFT meeting. July 17-19. Chicago.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Kong, F. (2015). Dielectric properties of dried vegetable powders and their temperature profile during radio frequency heating. 2015 MINI-SUMMIT in Food Safety, Policy and Sustainability. Oct 23-26. Keelung, Taiwan.
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Progress 09/01/14 to 08/31/15
Outputs
Target Audience:One paper was published in Journal of Food Engineering which is available for all the readers to access. One oral presentation was made to the attendees ofIMPI's 49th Microwave Power Symposium. One poster presentation was made to the attendees ofUSDA NIFA Project Director (PD) Meeting. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The graduate student attendedIMPI's 49th Microwave Power Symposium, June 16-18, 2015, inSan Diego, California. He also prepared manuscript which was accepted by the Journal of Food Engineering. How have the results been disseminated to communities of interest?One oral presentation was made in IMPI's 49th Microwave Power Symposium,June 16-18, 2015, inSan Diego, California. One poster presentation was made inUSDA NIFA Project Director (PD) Meeting, July 24, 2015, inPortland, Oregon. A paper was accepted by the Journal of Food Engineering. What do you plan to do during the next reporting period to accomplish the goals?We will continue to study the effect of compaction density on the dielectric properties of dried vegetable powder and peppers, and the related mechanisms. In addition, we are preparing a container to be used in RF oven to study the temperature uniformity. The uniformity of RF heating is critical affecting the food quality and safety. We will study strategies to improve the heating uniformity.
Impacts
What was accomplished under these goals?
The dielectric properties of selected vegetable powders, including broccoli powder, chili powder, onion, potato, etc., were determined, as related to the effect of moisture, temperature, frequency, and compaction density. Mathematical equationswere derived to correlate moisture, frequency, temperature, and the dielectric constant and loss factor. Penetration depth was characterized. The correlations between heating rates and the dielectric properties were statistically analyzed.
Publications
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2015
Citation:
Ozturk S, Kong F, Trabelsi S, Singh R. 2015. Dielectric properties of broccoli powder and its temperature profile during radio frequency heating. Journal of Food Engineering. In press.
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Progress 09/01/13 to 08/31/14
Outputs
Target Audience:An poster presentation was made to the attendees of 2014 IFT meeting. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The graduate student attended 2014 IFT meeting and presented a poster. How have the results been disseminated to communities of interest?A poster was presented in 2014 IFT meeting. What do you plan to do during the next reporting period to accomplish the goals?We will continue to study the dielectric properties of vegetable powders and investigate the temperature uniformity of the food powders during RF heating. A LCR meter a dielectric liquid test fixture (16452, Agilent Technologies, Palo Alto, CA) will be used for measuring the dielectric properties. Penetration depth will be characterized. The effect of moisture, temperature, and frequency and compaction density will be studied.
Impacts
What was accomplished under these goals?
The heating rates of selected vegetable powders, including broccoli powder, chili powder, onion, potato, etc.,under radiofrequency heating were determined.Samples were placed in a small plastic bottle (height of 4.8 cm x diameter of 2.9 cm), and heated individually in a 27.12 MHz RF oven from 20 to 80 °C. The temperature was recorded by every 5 s using a data logger with fiber optic sensor at the distance of 9 cm between electrodes.To determine the influence of moisture and compactiondensity on the heating rate, the samples were adjusted to achieve different moisture content and compaction density.?
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Samet Ozturk, Fanbin Kong, Vijendra Sharma. 2014. Temperature Profiles in Dried Vegetables During Radio Frequency Heating. 2014 IFT Annual Meeting, June 21 24, 2014, New Orleans, LA.
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