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Developing Hot Air-Assisted Radio Frequency Drying for In-shell Macadamia Nuts

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Abstract

Dehydration reduces water activity and extends shelf life of perishable agricultural products. The purpose of this research was to study the application of radio frequency (RF) energy in dehydration of in-shell Macadamia nuts and shorten the lengthy process times needed in conventional hot air drying operations. A pilot scale 27.12-MHz and 6-kW RF system was used to determine the operational parameters, the drying curve, and the quality attributes of the processed nuts. The results showed that an electrode gap of 15.5 cm and a hot air temperature of 50 °C provided an acceptable heating rate and stable sample temperatures, and were used for further drying tests. The drying curves showed an exponential decay and required 750 and 360 min to achieve the final moisture content of 0.030 kg water/kg dry solid (3.0 % dry basis) in whole nuts in hot air drying and RF heating/hot air combined drying, respectively. The drying kinetics of the nuts were described well by the Page model for hot air drying, but a logarithmic model was more suited for RF/hot air drying. Peroxide value and free fatty acid increased with the drying time both for hot air and RF drying but remained within acceptable range required by the nut industry. The RF process shows potential to provide rapid, uniform, and quality-acceptable drying technology for the nut industry.

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References

  • [AMS] Australian Macadamia Society. (2008). The Australian Macadamia Nut Industry. http://www.macadamias.org/, August, 2008.

  • [ANVISA] Agência Nacional de Vigilância Sanitária. (1999). Brasil, Resolução no. 482, de 23 de setembro de 1999. Brasília—DF, no. 3029, republicada em 20/06/2000.

  • AOAC. (2002). Official methods of analysis. Gaithersburg: Association of Official Analytical Chemists.

    Google Scholar 

  • AOCS. (2002). AOCS official methods and recommended practices of the American Oil Chemist’s Society (5th edn), in AOCS Society, Champaign.

  • Balakrishnan, P. A., Vedaraman, N., Sundar, V. J., Muralidharan, C., & Swaminathan, G. (2004). Radio frequency heating-a prospective leather drying system for future. Drying Technology, 22(8), 1969–1982.

    Article  Google Scholar 

  • Barber, H. (1983). Electroheat. London: Granada Publishing Limited.

    Google Scholar 

  • Borompichaichartkul, C., Luengsode, K., Chinprahast, N., & Devahastin, S. (2009). Improving quality of macadamia nut (Macadamia integrifolia) through the use of hybrid drying process. Journal of Food Engineering, 93, 348–353.

    Article  Google Scholar 

  • Buranasompob, A., Tang, J., Mao, R., & Swanson, B. G. (2003). Rancidity of walnuts and almonds affected by short time heat treatments for insect control. Journal of Food Processing and Preservation, 27, 445–464.

    Article  Google Scholar 

  • Clary, C. D., Wang, S. J., & Petrucci, V. E. (2005). Fixed and incremental levels of microwave power application on drying grapes under vacuum. Journal of Food Science, 70(5), 344–349.

    Article  Google Scholar 

  • Crank, J. (1970). The mathematics of diffusion. London: Oxford University Press.

    Google Scholar 

  • Cui, Z. W., Xu, S. Y., & Sun, D. W. (2005). Temperature changes during microwave-vacuum drying of sliced carrots. Drying Technology, 23, 1057–1074.

    Article  Google Scholar 

  • Dziak, J. (2008). Application of radio-frequency wave and microwave devices in drying and bleaching of wood pulp. Applied Thermal Engineering, 28, 1189–1195.

    Article  CAS  Google Scholar 

  • Farag, K. W., Marra, F., Lyng, J. G., Morgan, D. J., & Cronin, D. A. (2010). Temperature changes and power consumption during radio frequency tempering of beef lean/fat formulations. Food and Bioprocess Technology, 3(5), 732–740.

    Article  Google Scholar 

  • Farag, K. W., Lyng, J. G., Morgan, D. J., & Cronin, D. A. (2011). A comparison of conventional and radio frequency thawing of beef meats: effects on product temperature distribution. Food and Bioprocess Technology, 4(7), 1128–1136.

    Article  Google Scholar 

  • Feng, H., & Tang, J. (1998). Microwave finish drying of diced apples in a spouted bed. Journal of Food Science, 63(4), 679–683.

    Article  CAS  Google Scholar 

  • Feng, H., Tang, J., Cavalieri, R. P., & Plumb, O. A. (2001). Heat and mass transport in microwave drying of porous materials in a spouted bed. AICHE Journal, 47(7), 1499–1512.

    Article  CAS  Google Scholar 

  • Gao, M., Tang, J., Wang, Y., Powers, J., & Wang, S. (2010). Almond quality as influenced by radio frequency heat treatments for disinfestations. Postharvest Biology and Technology, 58(3), 234–240.

    Article  Google Scholar 

  • Gao, M., Tang, J., Villa-Rojas, R., Wang, Y., & Wang, S. (2011). Pasteurization process development for controlling Salmonella in in-shell almonds using radio frequency energy. Journal of Food Engineering, 104(2), 299–306.

    Article  Google Scholar 

  • Grag, M. L., Rudra, P., Blake, R., & Wills, R. (2003). Macadamia nut consumption lowers plasma cholesterol levels in hypercholesterolemic men. Journal of Nutrition, 133, 1060–1063.

    Google Scholar 

  • Guiné, R. P. F., Pinho, S., & Barroca, M. J. (2011). Study of the convective drying of pumpkin (Cucurbita maxima). Food and Bioproducts Processing, 89, 422–428.

    Article  Google Scholar 

  • Jiao, S., Johnson, J. A., Tang, J., & Wang, S. (2012). Industrial-scale radio frequency treatments for insect control in lentils. Journal of Stored Products Research, 48, 143–148.

    Article  Google Scholar 

  • Jumah, R. (2005). Modelling and simulation of continuous and intermittent radio frequency-assisted fluidized bed drying of grains. Food and Bioproducts Processing, 83(C3), 203–210.

    Article  Google Scholar 

  • Koral, T. (2004). Radio frequency heating and post-baking. Biscuit World Issue, 7(4).

  • Koumoutasakos, A., Avramidis, S., & Hatzikiriakos, S. G. (2001). Radio frequency vacuum drying of wood. II. Experimental model evaluation. Drying Technology, 19(1), 85–98.

    Article  Google Scholar 

  • Lagunas-Solar, M. C., Pan, Z., Zeng, N. X., Truong, T. D., Khir, R., & Amaratunga, K. S. P. (2007). Application of radio frequency power for non-chemical disinfestation of rough rice with full retention of quality attributes. Applied Engineering in Agriculture, 23, 647–654.

    Article  Google Scholar 

  • Lahsasni, S., Kouhila, M., Mahrouz, M., & Jaouhari, J. T. (2004). Drying kinetics of prickly pear peel (Opuntia ficus indica). Journal of Food Engineering, 61, 173–179.

    Article  Google Scholar 

  • Lam, P. S., Sokhansanj, S., Bi, X. T. T., Lim, C. J., & Larsson, S. H. (2012). Drying characteristics and equilibrium moisture content of steam-treated Douglas fir (Pseudotsuga menziesii L.). Bioresource Technology, 116, 396–402.

    Article  CAS  Google Scholar 

  • Lee, N. H., Li, C. Y., Zhao, X. F., & Park, M. J. (2010). Effect of pretreatment with high temperature and low humidity on drying time and prevention of checking during radio-frequency/vacuum drying of Japanese cedar pillar. Journal of Wood Science, 56(1), 19–24.

    Article  CAS  Google Scholar 

  • Li, C. Y., & Lee, N. H. (2008). The effect of compressive load on the moisture content of oak blocks during radio-frequency/vacuum drying. Forest Products Journal, 58(4), 34–38.

    Google Scholar 

  • Luechapattanaporn, K., Wang, Y., Wang, J., Tang, J., Hallberg, L. M., & Dunne, C. P. (2005). Sterilization of scrambled eggs in military polymeric trays by radio frequency energy. Journal of Food Science, 70(4), E288–E294.

    Article  CAS  Google Scholar 

  • Marinos-Kouris, D., & Maroulis, Z. B. (1995). Transport properties in the drying of solids. In A. S. Mujumdar (Ed.), Handbook of industrial drying (pp. 113–159). New York: Marcel Dekker.

    Google Scholar 

  • Marra, F., Zhang, L., & Lyng, J. G. (2009). Radio frequency treatment of foods: Review of recent advances. Journal of Food Engineering, 91(4), 497–508.

    Article  Google Scholar 

  • Metaxas, A. C., & Meredith, R. J. (1983). Industrial microwave heating. London: Peter Peregrinus Ltd.

    Google Scholar 

  • Mota, C. L., Luciano, C., Dias, A., Barroca, M. J., & Guiné, R. P. F. (2010). Convective drying of onion: Kinetics and nutritional evaluation. Food and Bioproducts Processing, 88, 115–123.

    Article  CAS  Google Scholar 

  • Murphy, A., Morrow, R., & Besley, L. (1992). Combined radiofrequency and forced-air drying of alfalfa. The Journal of Microwave Power and Electromagnetic Energy, 27(4), 223–232.

    Google Scholar 

  • Nelson, S. O. (1996). Review and assessment of radio-frequency and microwave energy for stored-grain insect control. Transactions of ASAE, 39, 1475–1484.

    Article  Google Scholar 

  • Orfeuil, M. (1987). Electric process heating: technologies/equipment/applications. Columbus: Battelle Press.

    Google Scholar 

  • Orsat, V. (1999). Radio-frequency thermal treatments for agri-food products, Ph.D. thesis, Department of Agricultural and Biosystems Engineering. McGill University, Ste-Anne de Bellevue.

  • Pound, J. (1973). Radio frequency heating in the timber industry. New York: Wiley.

    Google Scholar 

  • Ptasznik, W., Zygmunt, S., & Kudra, T. (1990). Simulation of RF-assisted convective drying for seed quality broad bean. Drying Technology, 8(5), 977–992.

    Article  Google Scholar 

  • [SAMGA] Southern African Macadamia Growers Association. (2011). Raw Macadamia product quality specifications. http://www.samac.org.za/quality.html

  • Silva, F. A., Marsaloli, A., Maximo, G. J., Silva, M., & Goncalves, L. A. G. (2006). Microwave assisted drying of macadamia nuts. Journal of Food Engineering, 77(3), 550–558.

    Article  Google Scholar 

  • Srinivasakannan, C., & Balasubramanian, N. (2009). Estimation of diffusion parameters in fluidized bed drying. Advanced Powder Technology, 20, 390–394.

    Article  Google Scholar 

  • Tulasidas, T. N., Raghavan, G. S. V., & Norris, E. R. (1993). Microwave and convective drying of grapes. Transactions of ASAE, 36(6), 1861–1865.

    Article  Google Scholar 

  • [USDA-NASS] United States Department of Agriculture-National Agricultural Statistics Service. (2011). National statistics of crops. http://www.nass.usda.gov/ QuickStats/index2.jsp, Washington, DC.

  • Wang, S., Ikediala, J. N., Tang, J., Hansen, J., Mitcham, E., Mao, R., et al. (2001). Radio frequency treatments to control codling moth in in-shell walnuts. Postharvest Biology and Technology, 22(1), 29–38.

    Article  Google Scholar 

  • Wang, S., Tang, J., Cavalieri, R. P., & Davis, D. (2003a). Differential heating of insects in dried nuts and fruits associated with radio frequency and microwave treatments. Transactions of the ASABE, 46(4), 1175–1182.

    Google Scholar 

  • Wang, S., Tang, J., Johnson, J. A., Mitcham, E., Hansen, J. D., Hallman, G., et al. (2003b). Dielectric properties of fruits and insect pests as related to radio frequency and microwave treatments. Biosystems Engineering, 85(2), 201–212.

    Article  Google Scholar 

  • Wang, W., Chen, G. H., & Gao, F. R. (2005). Effect of dielectric material on microwave freeze drying of skim milk. Drying Technology, 23(1–2), 317–340.

    Article  CAS  Google Scholar 

  • Wang, S., Monzon, M., Johnson, J. A., Mitcham, E. J., & Tang, J. (2007a). Industrial-scale radio frequency treatments for insect control in walnuts: I. Heating uniformity and energy efficiency. Postharvest Biology and Technology, 45, 240–246.

    Article  Google Scholar 

  • Wang, S., Monzon, M., Johnson, J. A., Mitcham, E. J., & Tang, J. (2007b). Industrial-scale radio frequency treatments for insect control in walnuts: II. Insect mortality and product quality. Postharvest Biology and Technology, 45, 247–253.

    Article  Google Scholar 

  • Wang, S., Tiwari, G., Jiao, S., Johnson, J. A., & Tang, J. (2010). Developing postharvest disinfestation treatments for legumes using radio frequency energy. Biosystems Engineering, 105(3), 341–349.

    Article  Google Scholar 

  • Wang, Y., Li, Y., Wang, S., Zhang, L., Gao, M., & Tang, J. (2011). Review of dielectric drying of foods and agricultural products. International Journal of Agricultural and Biological Engineering, 4(1), 1–19.

    Google Scholar 

  • Wang, Y., Zhang, L., Gao, M., Tang, J., & Wang, S. (2012). Temperature- and moisture-dependent dielectric properties of macadamia nut kernels. Food and Bioprocess Technology. doi:10.1007/s11947-012-0898-2.

  • Xu, Y. Y., Zhang, M., & Tu, D. Y. (2005). A two-stage convective air and vacuum freeze-drying technique for bamboo shoots. International Journal of Food Science and Technology, 40(6), 589–595.

    Article  CAS  Google Scholar 

  • Yaldýz, O., & Ertekýn, C. (2001). Thin layer solar drying of some vegetables. Drying Technology, 19, 583–597.

    Article  Google Scholar 

  • Yang, H., Sakai, N., & Watanabe, M. (2001). Drying model with non-isotropic shrinkage deformation undergoing simultaneous heat and mass transfer. Drying Technology, 19, 1441–1460.

    Article  CAS  Google Scholar 

  • Zhang, M., Tang, J., Mujumdar, A. S., & Wang, S. (2006). Trends in microwave-related drying of fruits and vegetables. Trends in Food Science and Technology, 17, 527–534.

    Article  Google Scholar 

  • Zopas, N. P., & Maroulis, Z. B. (1996). Effective moisture diffusivity estimation from drying data. A comparison between various methods of analysis. Drying Technology, 14(7&8), 1543–1573.

    Google Scholar 

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Acknowledgments

This research was conducted in the Department of Biological Systems Engineering, Washington State University (WSU), supported by grants from WSU Agricultural Research Center, and partially provided by the general program (grant no. 31171761) of National Natural Science Foundation of China and seed grant of Yangling International Academy of Modern Agriculture. We thank Island Princess Macadamia Nut Company, in Hawaii, USA for providing Macadamia nuts.

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Authors and Affiliations

  1. College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China

    Yunyang Wang & Li Zhang

  2. USDA-ARS San Joaquin Valley Agricultural Sciences Center, 9611 S. Riverbend Avenue, Parlier, CA, 93648, USA

    Judy Johnson

  3. College of Life Science, Yangtze University, Jingzhou, Hubei, 434025, China

    Mengxiang Gao

  4. Department of Biological Systems Engineering, Washington State University, 213 L.J. Smith Hall, Pullman, WA, 99164-6120, USA

    Juming Tang & Shaojin Wang

  5. Department of Food Science and Human Nutrition, Washington State University, Pullman, WA, 99164, USA

    Joseph R. Powers

  6. College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China

    Shaojin Wang

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  1. Yunyang Wang
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Correspondence to Shaojin Wang.

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Wang, Y., Zhang, L., Johnson, J. et al. Developing Hot Air-Assisted Radio Frequency Drying for In-shell Macadamia Nuts. Food Bioprocess Technol 7, 278–288 (2014). https://doi.org/10.1007/s11947-013-1055-2

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