Introduction
Sour cherries (Prunus cerasus L.) are relatively diverse and broadly distributed around the world, being found in Asia, Europe, and North America. Sour cherries have unique anthocyanin content, and rich in phenolic compounds. The fruits are generally used for processing purposes, such as for production juice and jam. The fruits of sour cherries can also be frozen and dried. One of the best methods for the preservation of agricultural product is drying, which involves removing water from the manufactured goods. Dried sour cherries have a long shelf life and therefore may be a fine alternative to fresh fruit all year round. There are no reports on the effect of microwave pretreatment on the hot air drying kinetics of sour cherries in the literature. Hence, the purpose of this study was to estimate the impacts of microwave pretreatment on the total phenolics, drying time, mass transfer kinetic, effective moisture diffusivity, total color difference index, shrinkage and rehydration of sour cherry. In addition, the moisture ratio changes of sour cherry during drying were modeled.
Material and Methods
Sour cherries were purchased from the market at Bahar, Hamedan Province, Iran. The average diameter of fresh sour cherries was 1.6 cm. In this study, the water content of fresh and dried sour cherries was calculated using an oven at 103°C for 5 h (Shimaz, Iran). In this research, the effect of microwave time on the drying time, effective moisture diffusivity coefficient and rehydration of sour cherries was investigated and drying kinetics were modeled. To apply the microwave pretreatment on the sour cherries, a microwave oven (Gplus, Model; GMW-M425S.MIS00, Goldiran Industries Co., Iran) was used under atmospheric pressure. In this work, the influence of the microwave pretreatment time at five levels of 0, 30, 60, 90, and 120 s (power=220W) on the cherries was examined. After taking out the treated sour cherries from microwave device, the samples were placed in the hot-air dryer (70°C) as a thin layers. The dehydration kinetics of sour cherries were explained using 7 simplified drying equations. Fick's second law of diffusion using spherical coordinates was used to calculate the moisture diffusivity of sour cherries at various hot-air drying conditions. The rehydration test was conducted with a water bath (R.J42, Pars Azma Co., Iran). Dried sour cherries were weighed and immersed for 30 min in distilled water in a 250 ml glass beaker at 50°C.
Results and Discussion
The results showed that microwave treatment led to an increase in moisture removal rate from the sour cherries, an increase in the effective moisture diffusivity coefficient, and, consequently, a decrease in drying time. By increasing the microwave time from 0 to 12 s, the average drying time of sour cherries in the hot-air dryer was decreased from 370 min to 250 min (p<0.05). The average effective moisture diffusivity coefficient calculated for the samples placed in the hot-air dryer was 4.25×10-10 m2/s. Increasing the microwave time from 0 to 120 s increased the average effective moisture diffusivity coefficient by 85%. The maximum amount of phenolic was related to the sample treated with microwave for 90 seconds. Microwave treatment time had no significant effect on the rehydration of dried sour cherries.
Conclusion
Kinetic modeling of weight changes of sour cherries during drying was carried out using models in the sources, followed the Page model was selected as the best model to predict moisture ratio changes under the selected experimental conditions. The mean values of sum of squares due to error, root mean square error, and r for all samples ranged from 0.001 to 0.007, 0.005 to 0.017, and 0.997 to 0.999, respectively. Generally, 120 s pre-treatment by microwave is the best condition for drying sour cherries. |
- Akbarian Meymand, M.J., Faraji Kafshgari, S., Mahmodi, E., & Vatankhah, M. (2015). The effect of using microwave pretreatment in drying roots nutmeg on antimicrobial properties against pathogenic bacteria and spoilage molds. Iranian Journal of Medical Microbiology, 9(2), 47-55.
- Amin Ekhlas, S., Pajohi-Alamoti, M.R., & Salehi, F. (2023). Effect of ultrasonic waves and drying method on the moisture loss kinetics and rehydration of sprouted wheat. Journal of Food Science and Technology (Iran), 20(135), 159-168. https://doi.org/10.22034/fsct.19.135.159
- Azadbakht, M., Vahedi Torshizi, M., Mahmoodi, M.J., & Ghazagh Jahed, R. (2021). Mathematical modeling of the biochemical properties of carrots by microwave drying with different pretreatments using response surface methodology. Food Engineering Research, 21(72), 35-56. https://doi.org/10.22092/fooder.2020.343389.1273
- Delgado, J.M.P.Q., & da Silva, M.V. (2014). Food Dehydration: Fundamentals, Modelling and Applications, in: Delgado, J.M.P.Q., Barbosa de Lima, A.G. (Eds.), Transport phenomena and drying of solids and particulate materials. Springer International Publishing, Cham, pp. 69-94.
- Doymaz, İ. (2007). Influence of pretreatment solution on the drying of sour cherry. Journal of Food Engineering, 78(2), 591-596. https://doi.org/10.1016/j.jfoodeng.2005.10.037
- Einafshar, S. (2014). Quality and microbial changes of four dried sour cherry by osmosis process through one year storage. Iranian Food Science and Technology Research Journal, 10(4), 363-374. https://doi.org/10.22067/ifstrj.v10i4.43732.
- Ghaderi, A., Abbasi, S., Motevali, A., & Minaei, S. (2011). Selection of a mathematical model for drying kinetics of sour cherry (Prunus cerasus) in a microwave-vacuum dryer. Iranian Journal of Nutrition Sciences and Food Technology, 6(2), 55-64.
- Kouchakzadeh, A., & Shafeei, S. (2010). Modeling of microwave-convective drying of pistachios. Energy Conversion and Management, 51(10), 2012-2015. https://doi.org/10.1016/j.enconman.2010.02.034
- 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
- Mohammadpour Mir, M.E., Nanvakenari, S., & Movagharnejad, K. (2020). Modeling and investigation of the performance of MLP and RBF during the paddy rice drying in microwave dryer. Iranian Food Science and Technology Research Journal, 16(2), 331-341. https://doi.org/10.22067/ifstrj.v16i2.80737
- Momenzadeh, L., Zomorodian, A.A., & Mowla, D. (2010). Applying artificial neural network for shrinkage prediction of green pea in a microwave assisted fluidized bed dryer. Iranian Food Science and Technology Research Journal, 6(4), 277-285. https://doi.org/10.22067/ifstrj.v6i4.9285
- Pourhaji, F., Tabatabaei Yazdi, F., Mortazavi, S.A., Mohebbi, M., & Mazaheri Tehrani, M. (2018). Foam mat drying of banana milk using microwave and evaluation of resulting powders’s properties. Iranian Food Science and Technology Research Journal, 14(2), 283-296. https://doi.org/10.22067/ifstrj.v0i0.60551
- Sahin, M., & Doymaz, İ. (2017). Estimation of cauliflower mass transfer parameters during convective drying. Heat and Mass Transfer, 53(2), 507-517. https://doi.org/10.1007/s00231-016-1835-0
- Salehi, F. (2020). Food industry machines and equipment. Bu-Ali Sina University Press, Hamedan, Iran.
- Salehi, F., Cheraghi, R., & Rasouli, M. (2022). Mass transfer kinetics (soluble solids gain and water loss) of ultrasound-assisted osmotic dehydration of apple slices. Scientific Reports, 12(1), 15392. https://doi.org/10.1038/s41598-022-19826-w
- Salehi, F., Razavi Kamran, H., & Goharpour, K. (2023). Effects of ultrasound time, xanthan gum, and sucrose levels on the osmosis dehydration and appearance characteristics of grapefruit slices: process optimization using response surface methodology. Ultrasonics Sonochemistry, 98, 106505. https://doi.org/10.1016/j.ultsonch.2023.106505
- Salehi, F., & Satorabi, M. (2021a). Effect of basil seed and xanthan gums coating on colour and surface change kinetics of peach slices during infrared drying. Acta Technologica Agriculturae, 24(3), 150-156. https://doi.org/10.2478/ata-2021-0025
- Salehi, F., & Satorabi, M. (2021b). Influence of infrared drying on drying kinetics of apple slices coated with basil seed and xanthan gums. International Journal of Fruit Science, 21(1), 519-527. https://doi.org/10.1080/15538362.2021.1908202
- Sharma, G.P., & Prasad, S. (2006). Optimization of process parameters for microwave drying of garlic cloves. Journal of Food Engineering, 75(4), 441-446. https://doi.org/10.1016/j.jfoodeng.2005.04.029
- Šumić, Z., Tepić, A., Vidović, S., Jokić, S., & Malbaša, R. (2013). Optimization of frozen sour cherries vacuum drying process. Food Chemistry, 136(1), 55-63. https://doi.org/10.1016/j.foodchem.2012.07.102
- Vega-Gálvez, A., Di Scala, K., Rodríguez, K., Lemus-Mondaca, R., Miranda, M., López, J., & Perez-Won, M. (2009). Effect of air-drying temperature on physico-chemical properties, antioxidant capacity, colour and total phenolic content of red pepper (Capsicum annuum, L. var. Hungarian). Food Chemistry, 117(4), 647-653. https://doi.org/10.1016/j.foodchem.2009.04.066
- Wojdyło, A., Figiel, A., Lech, K., Nowicka, P., & Oszmiański, J. (2014). Effect of convective and vacuum–microwave drying on the bioactive compounds, color, and antioxidant capacity of sour cherries. Food and Bioprocess Technology, 7(3), 829-841. https://doi.org/10.1007/s11947-013-1130-8
- Wray, D., & Ramaswamy, H.S. (2015). Novel concepts in microwave drying of foods. Drying Technology, 33(7), 769-783. https://doi.org/10.1080/07373937.2014.985793
|
