Ultrasound Pretreatment Prior to Hot Air Drying and Intermittent Microwave Drying of Apple Slices: Effect of Acoustic Density and Microwave Power
DOI:
https://doi.org/10.24925/turjaf.v13i6.1631-1644.7954Keywords:
Drying, Energy, Microwave, Rehydration, UltrasoundAbstract
This study investigated the impact of various drying techniques and ultrasound pretreatments on the drying kinetics, rehydration properties, energy efficiency, and quality parameters of apple slices. Apples were dried using hot-air drying at 55 °C and 65 °C, and intermittent microwave drying at 240 W and 400 W. US pretreatment was applied at acoustic densities of 60 and 80 W L⁻¹ prior to hot-air drying to assess its effect on mass transfer and quality. The drying behavior was modeled using both thin-layer mathematical models and artificial neural networks. Results revealed that US pretreatment significantly enhanced the drying rate and reduced drying time and energy consumption, particularly at higher acoustic density and temperature, while intermittent microwave drying achieved the shortest drying durations and lowest energy consumption. Among the models, the Midilli and Kucuk model best described the thin-layer drying data, although ANN models provided superior predictive performance across most conditions. Rehydration ratio was positively influenced by US pretreatment at lower temperatures but was adversely affected at higher temperatures and higher microwave power levels due to structural damage. Total phenolic content and antioxidant activity were preserved or enhanced by microwave drying, whereas US pretreatment showed no clear benefit and, in some cases, led to degradation, likely due to prolonged sonication and water immersion. Color values showed minimal undesirable changes with US pretreatment, and higher L* values (lightness) were retained in most cases. a* and b* values increased after drying processes. Principal component analysis (PCA) effectively differentiated treatment groups based on all measured parameters. US pretreated and unpretreated samples are positioned in the same place, while intermittent microwave dried and fresh samples are in a different plane. In conclusion, US pretreatment and microwave drying are promising technologies for improving drying efficiency and maintaining quality in dried apple products.
References
Adeyeye, S. A. O., Ashaolu, T. J., & Babu, A. S. (2022). Food drying: A review. Agricultural reviews, 1(8). https://doi.org/10.18805/ag.R-2537.
Akhoundzadeh Yamchi, A., Yeganeh, R., & Kouchakzadeh, A. (2022). Effect of ultrasonic pretreatment on drying kinetics and physio‐mechanical characteristics of peach slices. Journal of Food Process Engineering, 45(8), e14053. https://doi.org/10.1111/jfpe.14053
Aksüt, B., Polatcı, H., & Taşova, M. (2023). The effect of pre-treatment and drying temperatures on energy consumption and quality characteristics in drying of lemon (Citrus limon L.) slices. Journal of Thermal Analysis and Calorimetry, 148(19), 10415-10427. https://doi.org/10.1007/s10973-023-12362-3
Alp, D., & Bulantekin, Ö. (2021). The microbiological quality of various foods dried by applying different drying methods: a review. European Food Research and Technology, 247(6), 1333-1343. https://doi.org/10.1007/s00217-021-03731-z
Aradwad, P. P., Thirumani Venkatesh, A. K., & Mani, I. (2023). Infrared drying of apple (Malus domestica) slices: Effect on drying and color kinetics, texture, rehydration, and microstructure. Journal of Food Process Engineering, 46(2), e14218. https://doi.org/10.1111/jfpe.14218
Bagheri, N., & Dinani, S. T. (2019). Investigation of ultrasound-assisted convective drying process on quality characteristics and drying kinetics of zucchini slices. Heat and Mass Transfer/Waerme- Und Stoffuebertragung, 55(8), 2153–2163. https://doi.org/10.1007/s00231-019-02573-6
Bai, J. W., Zhang, L., Aheto, J. H., Cai, J. R., Wang, Y. C., Sun, L., & Tian, X. Y. (2023). Effects of different pretreatment methods on drying kinetics, three-dimensional deformation, quality characteristics and microstructure of dried apple slices. Innovative Food Science & Emerging Technologies, 83, 103216. https://doi.org/10.1016/j.ifset.2022.103216
Beigi, M. (2016). Hot air drying of apple slices: dehydration characteristics and quality assessment. Heat and Mass Transfer, 52(8), 1435-1442. https://doi.org/10.1007/s00231-015-1646-8
Bozkir, H., Rayman Ergün, A., Tekgül, Y., & Baysal, T. (2019). Ultrasound as pretreatment for drying garlic slices in microwave and convective dryer. Food science and biotechnology, 28, 347-354. https://doi.org/10.1007/s10068-018-0483-1
Çetin, N., & Sağlam, C. (2023). Effects of ultrasound pretreatment assisted drying methods on drying characteristics, physical and bioactive properties of windfall apples. Journal of the Science of Food and Agriculture, 103(2), 534-547. https://doi.org/10.1002/jsfa.12164
Choi, S. H., Ahn, J. B., Kim, H. J., Im, N. K., Kozukue, N., Levin, C. E., & Friedman, M. (2012). Changes in free amino acid, protein, and flavonoid content in jujube (Ziziphus jujube) fruit during eight stages of growth and antioxidative and cancer cell inhibitory effects by extracts. Journal of agricultural and food chemistry, 60(41), 10245-10255. https://doi.org/10.1021/jf302848u
Darıcı, M., Süfer, Ö., & Simsek, M. (2021). Determination of microwave drying and rehydration kinetics of green peppers with the bioactive and textural properties. Journal of Food Process Engineering, 44(8), e13755. https://doi.org/10.1111/jfpe.13755
Demiray, E., Seker, A., & Tulek, Y. (2017). Drying kinetics of onion (Allium cepa L.) slices with convective and microwave drying. Heat and Mass Transfer, 53, 1817-1827. https://doi.org/10.1007/s00231-016-1943-x
Demiray, E., Yazar, J. G., Aktok, Ö., Çulluk, B., Çalışkan Koç, G., & Pandiselvam, R. (2023). The effect of drying temperature and thickness on the drying kinetic, antioxidant activity, phenolic compounds, and color values of apple slices. Journal of Food Quality, 2023(1), 7426793. https://doi.org/10.1155/2023/7426793
Eroğlu, S. (2024). Çekirdekli ve Çekirdeksiz Nar Tanelerinin Ultrason Ön İşlemli Kurutma Kinetiğinin En Çok İki Parametre İçeren İnce Tabaka Modelleri Kullanılarak İncelenmesi. Turkish Journal of Agriculture-Food Science and Technology, 12(7), 1129-1136. https://doi.org/10.24925/turjaf.v12i7.1129-1136.6805
Evin, D. (2012). Thin layer drying kinetics of Gundelia tournefortii L. Food and bioproducts processing, 90(2), 323-332. https://doi.org/10.1016/j.fbp.2011.07.002
FAOSTAT (2025). https://www.fao.org/faostat/en/#data/QCL Access date: 25.05.2025
Fathi, F., N. Ebrahimi, S., Matos, L. C., PP Oliveira, M. B., & Alves, R. C. (2022). Emerging drying techniques for food safety and quality: A review. Comprehensive Reviews in Food Science and Food Safety, 21(2), 1125-1160. https://doi.org/10.1111/1541-4337.12898
Fijalkowska, A., Nowacka, M., Wiktor, A., Sledz, M., & Witrowa‐Rajchert, D. (2016). Ultrasound as a pretreatment method to improve drying kinetics and sensory properties of dried apple. Journal of Food Process Engineering, 39(3), 256-265. https://doi.org/10.1111/jfpe.12217
Haider, I., & Choubey, V. K. (2024). Identifying fruit and vegetable losses and waste causing factors in supply chain towards achieving sustainable consumption and production. Environment, Development and Sustainability, 1-30. https://doi.org/10.1007/s10668-024-04668-5
Henderson, S. M., & Pabis, S. (1961). Grain drying theory, I. Temperature effect on drying coefficient. J. Agr. Eng. Res., 6(3), 169-173.
Horuz, E., Bozkurt, H., Karataş, H., & Maskan, M. (2017). Effects of hybrid (microwave-convectional) and convectional drying on drying kinetics, total phenolics, antioxidant capacity, vitamin C, color and rehydration capacity of sour cherries. Food chemistry, 230, 295-305. https://doi.org/10.1016/j.foodchem.2017.03.046
Jakubczyk, E., Rybak, K., Witrowa-Rajchert, D., Wiktor, A., Rąbkowski, R., & Nowacka, M. (2024). Convective drying with the application of ultrasonic pre-treatment: The effect of applied conditions on the selected properties of dried apples. Foods, 13(23), 3893. https://doi.org/10.3390/foods13233893
Jedlińska, A., Rybak, K., Samborska, K., Barańska-Dołomisiewicz, A., Skarżyńska, A., Trusińska, M., ... & Nowacka, M. (2025). Hybrid Drying Method: Influence of Pre-Treatment and Process Conditions of Ultrasound-Assisted Drying on Apple Quality. Applied Sciences, 15(10), 5309. https://doi.org/10.3390/app15105309
Kahraman, O., Malvandi, A., Vargas, L., & Feng, H. (2021). Drying characteristics and quality attributes of apple slices dried by a non-thermal ultrasonic contact drying method. Ultrasonics Sonochemistry, 73, 105510. https://doi.org/10.1016/j.ultsonch.2021.105510
Karabacak, A. Ö., Suna, S., Tamer, C. E., & Çopur, Ö. U. (2018). Effects of oven, microwave and vacuum drying on drying characteristics, colour, total phenolic content and antioxidant capacity of celery slices. Quality Assurance and Safety of Crops & Foods, 10(2), 193-205. https://doi.org/10.3920/QAS2017.1197
Khoshhal, A., Dakhel, A. A., Etemadi, A., & Zereshki, S. (2010). Artificial neural network modeling of apple drying process. Journal of food process engineering, 33, 298-313. https://doi.org/10.1111/j.1745-4530.2009.00435.x
Kian-Pour, N. (2023). Effect of ethanol immersion and ultrasound pretreatments on the kinetics of convective drying of quince. Gıda, 48(5), 1099-1108. https://doi.org/10.15237/gida.GD23082
Kurtulmuş, F., Polat, A., & İzli, N. (2020). Yapay Sinir Ağları Kullanarak Kayısının Farklı Kurutma Yöntemleriyle Kurutulmasında Kuruma Hızı ve Nem İçeriği Parametrelerinin Modellenmesi. ÇOMÜ Ziraat Fakültesi Dergisi, 8(2), 261-269. https://doi.org/10.33202/comuagri.733166
Lv, W., Lv, H., Jin, X., Cui, Z., & Su, D. (2020). Effects of ultrasound-assisted methods on the drying processes and quality of apple slices in microwave drying. Drying Technology, 38(13), 1806-1816. https://doi.org/10.1080/07373937.2019.1666274
Macedo, L. L., Corrêa, J. L. G., Júnior, I. P., da Silva Araújo, C., & Vimercati, W. C. (2022). Intermittent microwave drying and heated air drying of fresh and isomaltulose (Palatinose) impregnated strawberry. Lwt, 155, 112918.
Manrich, A. (2024). Apple industry: Wastes and possibilities. International Journal on Agriculture Research and Environmental Sciences, 5(1), 1-10. https://doi.org/0.51626/ijares.2024.05.00043
Maskan, M. (2000). Microwave/air and microwave finish drying of banana. Journal of food engineering, 44(2), 71-78. https://doi.org/10.1016/S0260-8774(99)00167-3
McGhie, T. K., & Ainge, G. D. (2002). Color in fruit of the genus Actinidia: carotenoid and chlorophyll compositions. Journal of Agricultural and Food Chemistry, 50(1), 117-121. https://doi.org/10.1021/jf010677l
Méndez, E. K., Orrego, C. E., Manrique, D. L., Gonzalez, J. D., & Vallejo, D. (2015). Power ultrasound application on convective drying of banana (Musa paradisiaca), mango (Mangifera indica L.) and guava (Psidium guajava L.). Int J Biotechnol Bioeng, 9(10), 1100-5.
Musielak, G., Mieszczakowska-Frąc, M., & Mierzwa, D. (2024). Convective Drying of Apple Enhanced with Microwaves and Ultrasound—Process Kinetics, Energy Consumption, and Product Quality Approach. Applied Sciences, 14(3), 994. https://doi.org/10.3390/app14030994
Nowacka, M., Dadan, M., Janowicz, M., Wiktor, A., Witrowa‐Rajchert, D., Mandal, R., ... & Janiszewska‐Turak, E. (2021). Effect of nonthermal treatments on selected natural food pigments and color changes in plant material. Comprehensive Reviews in Food Science and Food Safety, 20(5), 5097-5144. https://doi.org/10.1111/1541-4337.12824
Nowacka, M., Wiktor, A., Śledź, M., Jurek, N., & Witrowa-Rajchert, D. (2012). Drying of ultrasound pretreated apple and its selected physical properties. Journal of Food Engineering, 113(3), 427-433. https://doi.org/10.1016/j.jfoodeng.2012.06.013
Omari, A., Behroozi‐Khazaei, N., & Sharifian, F. (2018). Drying kinetic and artificial neural network modeling of mushroom drying process in microwave‐hot air dryer. Journal of Food Process Engineering, 41(7), e12849. https://doi.org/10.1111/jfpe.12849
Ozcan-Sinir, G., Ozkan-Karabacak, A., Tamer, C. E., & Copur, O. U. (2018). The effect of hot air, vacuum and microwave drying on drying characteristics, rehydration capacity, color, total phenolic content and antioxidant capacity of Kumquat (Citrus japonica). Food Science and Technology, 39, 475-484. https://doi.org/10.1590/fst.34417
Page, G. E. (1949). Factors Influencing the Maximum Rates of Air Drying Shelled Corn in Thin layers. Purdue University.
Radojčin, M., Pavkov, I., Bursać Kovačević, D., Putnik, P., Wiktor, A., Stamenković, Z., ... & Gere, A. (2021). Effect of selected drying methods and emerging drying intensification technologies on the quality of dried fruit: A review. Processes, 9(1), 132. https://doi.org/10.3390/pr9010132
Rasooli Sharabiani, V., Kaveh, M., Abdi, R., Szymanek, M., & Tanaś, W. (2021). Estimation of moisture ratio for apple drying by convective and microwave methods using artificial neural network modeling. Scientific reports, 11(1), 9155. https://doi.org/10.1038/s41598-021-88270-z
Ricce, C., Rojas, M. L., Miano, A. C., Siche, R., & Augusto, P. E. D. (2016). Ultrasound pre-treatment enhances the carrot drying and rehydration. Food Research International, 89, 701-708. https://doi.org/10.1016/j.foodres.2016.09.030
Rodríguez, Ó., Eim, V., Rosselló, C., Femenia, A., Cárcel, J. A., & Simal, S. (2018). Application of power ultrasound on the convective drying of fruits and vegetables: effects on quality. Journal of the Science of Food and Agriculture, 98(5), 1660-1673.
Rybak, K., Wiktor, A., Witrowa-Rajchert, D., Parniakov, O., & Nowacka, M. (2021). The quality of red bell pepper subjected to freeze-drying preceded by traditional and novel pretreatment. Foods, 10(2), 226. https://doi.org/10.3390/foods10020226
Salehi, F., Goharpour, K., & Kamran, H. R. (2024). Effects of different pretreatment techniques on the color indexes, drying characteristics and rehydration ratio of eggplant slices. Results in Engineering, 21, 101690. https://doi.org/10.1016/j.rineng.2023.101690
Sarkar, T., Salauddin, M., Hazra, S. K., Choudhury, T., & Chakraborty, R. (2021). Comparative Approach of Artificial Neural Network and Thin Layer Modelling for Drying Kinetics and Optimization of Rehydration Ratio for Bael (Aegle Marmelos (L) Correa) Powder Production. Economic Computation & Economic Cybernetics Studies & Research, 55(1). https://doi.org/10.24818/18423264/55.1.21.11
Singleton, V. L., & Rossi, J. A. (1965). Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents. American journal of Enology and Viticulture, 16(3), 144-158.
Szadzińska, J., & Mierzwa, D. (2021). The influence of hybrid drying (microwave-convective) on drying kinetics and quality of white mushrooms. Chemical Engineering and Processing-Process Intensification, 167, 108532. https://doi.org/10.1016/j.cep.2021.108532
Taghinezhad, E., Kaveh, M., Szumny, A., Figiel, A., & Blasco, J. (2023). Qualitative, energy and environmental aspects of microwave drying of pre-treated apple slices. Scientific Reports, 13(1), 16152. https://doi.org/10.1038/s41598-023-43358-6
Tao, Y., Han, M., Gao, X., Han, Y., Show, P. L., Liu, C., ... & Xie, G. (2019). Applications of water blanching, surface contacting ultrasound-assisted air drying, and their combination for dehydration of white cabbage: Drying mechanism, bioactive profile, color and rehydration property. Ultrasonics sonochemistry, 53, 192-201. https://doi.org/10.1016/j.ultsonch.2019.01.003
Tepe, T. K. (2024a). Effect of pretreatments on drying characteristics, rehydration properties, and total energy consumption of carrot slices: comparison between thin layer mathematical modelling and artificial neural network modelling. Biomass Conversion and Biorefinery, 14(1), 1373-1387. https://doi.org/10.1007/s13399-023-04925-z
Tepe, T. K. (2024b). Convective drying of golden delicious apple enhancement: drying characteristics, artificial neural network modeling, chemical and ATR-FTIR analysis of quality parameters. Biomass Conversion and Biorefinery, 14(12), 13513-13531. https://doi.org/10.1007/s13399-024-05562-w
Tepe, T. K., & Tepe, B. (2020). The comparison of drying and rehydration characteristics of intermittent-microwave and hot-air dried-apple slices. Heat and Mass Transfer, 56(11), 3047-3057. https://doi.org/10.1007/s00231-020-02907-9
Tepe, T. K., & Tepe, F. B. (2024). Improvement of pear slices drying by pretreatments and microwave-assisted convective drying method: drying characteristics, modeling of artificial neural network, principal component analysis of quality parameters. Journal of Thermal Analysis and Calorimetry, 149(14), 7313-7328. https://doi.org/10.1007/s10973-024-13280-8
Thaipong, K., Boonprakob, U., Crosby, K., Cisneros-Zevallos, L., & Byrne, D. H. (2006). Comparison of ABTS, DPPH, FRAP, and ORAC assays for estimating antioxidant activity from guava fruit extracts. Journal of food composition and analysis, 19(6-7), 669-675. https://doi.org/10.1016/j.jfca.2006.01.003
Thuy, N. M., Hao, H. V., Giau, T. N., Minh, V. Q., & Tai, N. V. (2025). Mathematical and artificial neural network modeling for describing the infrared drying process of Moringa oleifera leaves and evaluation of product quality. Biomass Conversion and Biorefinery, 1-11. https://doi.org/10.1007/s13399-025-06731-1
Tüfekçi, S., & Özkal, S. G. (2020). Investigation of effect of ultrasound pretreatment on drying and rehydration characteristics and microstructure of apple slices. Yuzuncu Yıl University Journal of Agricultural Sciences, 30, 950-962. https://doi.org/10.29133/yyutbd.698826
Tunckal, C., & Doymaz, İ. (2020). Performance analysis and mathematical modelling of banana slices in a heat pump drying system. Renewable Energy, 150, 918-923. https://doi.org/10.1016/j.renene.2020.01.040
Vega-Gálvez, A., Ah-Hen, K., Chacana, M., Vergara, J., Martínez-Monzó, J., García-Segovia, P., ... & Di Scala, K. (2012). Effect of temperature and air velocity on drying kinetics, antioxidant capacity, total phenolic content, colour, texture and microstructure of apple (var. Granny Smith) slices. Food chemistry, 132(1), 51-59. https://doi.org/10.1016/j.foodchem.2011.10.029
Wang, J., Xiao, H. W., Ye, J. H., Wang, J., & Raghavan, V. (2019). Ultrasound pretreatment to enhance drying kinetics of kiwifruit (Actinidia deliciosa) slices: pros and cons. Food and bioprocess technology, 12, 865-876. https://doi.org/10.1007/s11947-019-02256-4
Wu, X. F., Zhang, M., Mujumdar, A. S., & Yang, C. H. (2020). Effect of ultrasound-assisted osmotic dehydration pretreatment on the infrared drying of Pakchoi Stems. Drying Technology. 38 (15), 2015-2026. https://doi.org/10.1080/07373937.2019.1608232
Xu, B., Tiliwa, E. S., Yan, W., Azam, S. R., Wei, B., Zhou, C., ... & Bhandari, B. (2022). Recent development in high quality drying of fruits and vegetables assisted by ultrasound: A review. Food Research International, 152, 110744. https://doi.org/10.1016/j.foodres.2021.110744
Yıldız, A. K., Polatcı, H., & Uçun, H. (2015). Farklı Kurutma Şartlarında Muz (Musa cavendishii) Meyvesinin Kurutulması ve Kurutma Kinetiğinin Yapay Sinir Ağları ile Modellenmesi. Tarım Makinaları Bilimi Dergisi, 11(2), 173-178.
Zhu, Y., Pan, Z., McHugh, T. H., & Barrett, D. M. (2010). Processing and quality characteristics of apple slices processed under simultaneous infrared dry-blanching and dehydration with intermittent heating. Journal of food engineering, 97(1), 8-16. https://doi.org/10.1016/j.jfoodeng.2009.07.021
Downloads
Published
How to Cite
Issue
Section
License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
