An efficient microwave milk pasteurization system requires a rigorous temperature dependent dielectric model of the milk, since the performance of milk pasteurization strongly depends on its dielectric properties. This paper describes the dielectric modelling of cows raw milk during batch (Vat) pasteurization which covers the frequencies from 0.2 GHz to 6 GHz. An open-ended coaxial sensor is used for the measurements of dielectric constant, loss factor, and ionic conductivity at temperature range of 25°C to 75°C with an interval of 5°C. Combinations of Cole-Davison and Debye equations are modified to fit the dielectric measurements. It was found that the measured dielectric constant decreased as the frequency increased, while the high temperature processed produce lower in a convergence manner toward 6 GHz. The loss factor exhibited high losses at higher temperature and lower frequencies, as well as converged at 1.9 GHz then diverged up to 6 GHz. Three relaxation processes are dominated at all temperature treatments within the frequency range. The relaxation time, τ, and the activation energy, Q, are modelled based on linear fitting of measured data according to Debye and Arrhenius approaches.
Suhail Najm Abdullah,
You Kok Yeow,
Nor Hisham Khamis,
Cheong Yew Chong,
"Modelling the Dielectric Properties of Cow's Raw Milk Under Vat Pasteurization," Progress In Electromagnetics Research M,
Vol. 84, 157-166, 2019. doi:10.2528/PIERM19052202
1. Haug, A., A. T. Hostmark, and O. M. Harstad, "Bovine milk in human nutrition - A review," Lipids in Health and Disease, Vol. 6, No. 1, 25, Sep. 2007. doi:10.1186/1476-511X-6-25
2. Bryan, F. L., "Epidemiology of milk-borne diseases," Journal of Food Protection, Vol. 46, No. 7, 637-649, Jul. 1983. doi:10.4315/0362-028X-46.7.637
3. Bansal, B. and X. D. Chen, "A critical review of milk fouling in heat exchangers," Comprehensive Reviews in Food Science and Food Safety, Vol. 5, No. 2, 27-33, Apr. 2006. doi:10.1111/j.1541-4337.2006.tb00080.x
4. Hamid, M. A. K., R. J. Boulanger, S. C. Tong, R. A. Gallop, and R. R. Pereira, "Microwave pasteurization of raw milk," Journal of Microwave Power, Vol. 4, No. 4, 272-275, Jan. 1969. doi:10.1080/00222739.1969.11688733
5. Wang, Y., T. D. Wig, J. Tang, and L. M. Hallberg, "Dielectric properties of foods relevant to RF and microwave pasteurization and sterilization," Journal of Food Engineering, Vol. 57, No. 3, 257-268, 2003. doi:10.1016/S0260-8774(02)00306-0
6. Nunes, A. C., X. Bohigas, and J. Tejada, "Dielectric study of milk for frequencies between 1 and 20 GHz," Journal of Food Engineering, Vol. 76, No. 2, 250-255, 2006. doi:10.1016/j.jfoodeng.2005.04.049
7. Mudgett, R. E., A. C. Smith, D. I. C. Wang, and S. A. Goldblith, "Prediction of dielectric properties in non-fat milk at frequencies and temperatures of interest in microwave processing," Journal of Food Science, Vol. 39, No. 1, 52-54, Jan. 1974. doi:10.1111/j.1365-2621.1974.tb00985.x
8. Zhu, X., W. Guo, and Y. Jia, "Temperature-dependent dielectric properties of raw Cow's and Goat's milk from 10 to 4,500 MHz relevant to radio-frequency and microwave pasteurization process," Food and Bioprocess Technology, Vol. 7, No. 6, 1830-1839, Jun. 2014. doi:10.1007/s11947-014-1255-4
9. Martins, C. P. C., R. N. Cavalcanti, S. M. Couto, J. Moraes, E. A. Esmerino, M. C. Silva, R. S. L. Raices, J. A. W. Gut, H. S. Ramaswamy, C. C. Tadini, et al. "Microwave processing: Current background and effects on the physicochemical and microbiological aspects of dairy products," Comprehensive Reviews in Food Science and Food Safety, Vol. 18, No. 1, 67-83, Wiley Online Library, 2019. doi:10.1111/1541-4337.12409
10. Leite, J. A. S., V. S. Quintal, and C. C. Tadini, "Dielectric properties of infant formulae, human milk and whole and low-fat cow milk relevant for microwave heating," International Journal of Food Engineering, De Gruyter, 2019.
11. Salema, A. A., Y. K. Yeow, K. Ishaque, F. N. Ani, M. T. Afzal, and A. Hassan, "Dielectric properties and microwave heating of oil palm biomass and biochar," Industrial Crops and Products, Vol. 50, 366-374, 2013. doi:10.1016/j.indcrop.2013.08.007
12. Nelson, S. O. and A. K. Datta, "Dielectric properties of food materials and electric field interactions," Handbook of Microwave Technology for Food Applications, 69-114, 2001.
13. You, K. Y., Z. Abbas, M. F. A. Malek, E. M. Cheng, and H. K. Mun, "Modeling of dielectric relaxation for lossy materials at microwave frequencies using polynomial approaches," Jurnal Teknologi, Vol. 58, No. 1, 2012.
14. Qian, F., J. Sun, D. Cao, Y. Tuo, S. Jiang, and G. Mu, "Experimental and modelling study of the denaturation of milk protein by heat treatment," Korean Journal for Food Science of Animal Resources, Vol. 37, No. 1, 44-51, 2017. doi:10.5851/kosfa.2017.37.1.44
15. Zhu, X., W. Guo, Y. Jia, and F. Kang, "Dielectric properties of raw milk as functions of protein content and temperature," Food and Bioprocess Technology, Vol. 8, No. 3, 670-680, Mar. 2015. doi:10.1007/s11947-014-1440-5
16. Herve, A. G., J. Tang, L. Luedecke, and H. Feng, "Dielectric properties of cottage cheese and surface treatment using microwaves," Journal of Food Engineering, Vol. 37, No. 4, 389-410, 1998. doi:10.1016/S0260-8774(98)00102-2
17. Yeow, Y. K., Z. Abbas, K. Khalid, and M. Z. A. Rahman, "Improved dielectric model for polyvinyl alcohol-water hydrogel at microwave frequencies," American Journal of Applied Sciences, Vol. 7, No. 2, 270-276, Feb. 2010. doi:10.3844/ajassp.2010.270.276
18. Guetouache, M., Guessas, Bettache, Medjekal, and Samir, "Composition and nutritional value of raw milk," Issues in Biological Sciences and Pharmaceutical Research, Vol. 2, No. 10, 115-122, 2014.
19. Liebe, H. J., G. A. Hufford, and T. Manabe, "A model for the complex permittivity of water at frequencies below 1 THz," International Journal of Infrared and Millimeter Waves, Vol. 12, No. 7, 659-675, Jul. 1991. doi:10.1007/BF01008897
20. Makino, T. and S.-I. Taneya, "Dielectric properties of powdered food," The Japan Society of Applied Physics, Vol. 32, No. 1, 10-16, Jan. 1963.
21. Hendrickx, M., Z. Weng, G. Maesmans, and P. Tobback, "Validation of a time-temperature-integrator for thermal processing of foods under pasteurization conditions," International Journal of Food Science & Technology, Vol. 27, No. 1, 21-31, 1992. doi:10.1111/j.1365-2621.1992.tb01174.x