The effects of solar drying on drying kinetics and effective moisture diffusivity of pistachio nut

Subject Areas :

Mohsen Mokhtarian ¹ , Hamid Tavakolipour ² , Ahmad Kalbasi-Ashtari ³ , Fatemeh Koushki ⁴

1 - Department of Food Science and Technology, Roudehen Branch, Islamic Azad University, Roudehen, Iran
2 - Department of Food Science and Technology, Sabzevar Branch, Islamic Azad University, Sabzevar, Iran
3 - Department of Food Science and Technology, Faculty of Agricultural Technology and Engineering, University of Tehran, Karaj, Iran
4 - Department of Food Science and Technology, Roudehen Branch, Islamic Azad University, Roudehen, Iran

Received: 2021-09-12 Accepted : 2021-12-10 Published : 2021-12-20

Keywords: Solar dryer /, Pistachio nut (<i>Pistacia vera</i> L.) /, Clean and renewable energy /, Drying kinetics,

Abstract :

This research aimed to investigate the process of pistachios solar drying in two different conditions of the designed dryer (recycle and without recycle modes). As well, in this study, the drying kinetics curves of pistachio were drawn and its dewatering behavior was monitored by empirical models. Furthermore, the mass transfer rate (MTR) of the examined product during drying in two noted modes was determined by Fick’s 2nd law. Maximum, minimum, and average values of collector output air temperature were recorded 54.20, 32.30, and 42.99oC & 47.10, 30.70, and 40.03oC in air recycle and without air recycle modes, respectively. The results dedicated that, 18.75 % saving in drying time was obtained for air recycle mode compared with without air recycle mode. Also, the obtained data revealed that the drying rate of pistachio nut under recycle mode was higher than that of pistachio nut under without recycle mode, especially during the first hours of drying. Moreover, the empirical modeling showed that the Parabolic and Diamante et al. models were found to be the most suitable for describing drying curve of the thin layer solar drying process of whole pistachio nut under recycle and without recycle modes, respectively. In addition, the highest value of effective moisture diffusivity was observed in solar dried pistachio nut under air recycle mode with the Deff value of 2.26×10-6 m2/h (R2=0.9265).

References:

1. FAO Stat Database. Available from http://faostat.fao.org; 2018.


2. Madamba PS, Driscoll RH, Buckle KA. The thin layer drying characteristic of garlic slices. Journal of Food Engineering. 1996;29:75-97.


3. Tunde-Akintunde TY. Mathematical modeling of sun and solar drying of chilli pepper. Renewable Energy. 2011;36:2139-45.


4. Kavak Akpinar E. Drying of mint leaves in a solar dryer and under open sun: Modelling, performance analyses. Energy Conversion and Management. 2010;51:2407-18.


5. Renewable energy organization of Iran. Available from http://www.suna.org.ir, 2015.


6. Mokhtarian M, Tavakolipour H, Kalbasi-Ashtari, A. Effects of solar drying along with air recycling system on physicochemical and sensory properties of dehydrated pistachio nuts. LWT-Food Science and Technology. 2017;75:202-9.


7. Mokhtarian M, Tavakolipour H, Kalbasi-Ashtari, A. Energy and exergy analysis in solar drying of pistachio with air recycling system. Drying Technology. 2016;34(12):1484-500.


8. Tavakolipour H. Postharvest operations of pistachio nuts. Journal of Food Science and Technology. 2013;8(3):1124-30.


9. Kouchakzadeh A. The effect of acoustic and solar energy on drying process of pistachios. Journal of Energy Conversion and Management. 2013;67:351-6.


10. Tavakolipour H, Mokhtarian M. Neural network approaches for prediction of pistachio drying kinetics. International Journal of Food Engineering. 2012;8(3):Article 42.


11. Kashaninejad M, Mortazavi A, Safekordi A, Tabil LG. Thin-layer drying characteristics and modeling of pistachio nuts. Journal of Food Engineering. 2007;78:98-108.


12. Gazor HR, Minaei, S. Influence of temperature and air velocity on drying time and quality parameters of pistachio (Pistacia vera). Drying Technology. 2005;23:2463-75.


13. Midilli A, Kucuk H. Mathematical modeling of thin layer drying of pistachio by using solar energy. Energy Conversion and Management. 2003;44:1111-22.


14. Tavakolipour H, Mokhtarian M. Unit operation in food engineering. Ayizh publisher (In Persian); 2019.


15. Amiri chayjan R, Tabatabaei bahrabad SM, Rahimi Sardari F. Modeling Infrared-covective drying of pistachio nuts under fixed and fluidized bed conditions. Journal of Food Processing and Preservation. 2013;38:1224-33.


16. Tavakolipour H. Drying kinetics of pistachio nuts (Pistacia vera). World Applied Sciences Journal. 2011;12(9):1639-46.


17. Crank J. Mathematics of diffusions. Oxford University Press, London. U.K; 1975.


18. Chayjan RA, Esna-Ashari M. Isosteric heat and entropy modeling of pistachio cultivars using neural network approach. Journal of Food Processing and Preservation. 2011;35:524-32.


19. Kouchaczadeh A, Shafeei S. Modeling of microwave-convective drying of pistachios. Energy Conversion and Management. 2010;51:2012-2015.


20. Rizvi SSH. Thermodynamic properties of foods in dehydration. In M. A. Rao & S. S. H. Rizvi (Eds.), Engineering Properties of Foods. NY: Marcel Dekker Inc; 1986.