Main Article Content



color properties, convective drying, moisture content, rehydration capacity


This study evaluated the effects of drying temperature and pre-treatment on the rehydration capacity and color parameters of sliced pears (cv. Ankara). Drying trials were conducted at 55, 65, and 75°C. Pre-treatment consisted of immersion of pear slices in a citric-acid solution or blanching in hot water. Pre-treatment was found to have a significant effect on both rehydration capacity and color, with higher temperatures and pre-treatment resulting in decreases in drying time and increases in rehydration capacity. Effective diffusivity values ranged between 1.12×10-10 and 2.94×10-10m2/s.  Blanched pear slices had the lowest Ea values (15.51 kJ/mol), followed by the samples immersed in citric acid (28.03 kJ/mol) and the untreated samples (33.48 kJ/mol). The  Midilli et al. model displayed the best fit to the drying data of five models tested based on the statistical criteria evaluated. Natural color of fresh pear was best preserved with lower drying temperatures and pre-treatment with citric acid.

Abstract 199 | pdf Downloads 209


Agrawal Y.C. and Singh R.D. 1977. Thin layer drying studies on short grain rice. ASAE Paper No: 3531 ASAE, St. Joseph, MI.

Amiripour M., Habibi-Najafi M.B., Mohebbi M. and Emadi B. 2015. Optimization of osmo-vacuum drying of pear (Pyrus communis L.) using response surface methodology. J Food Meas. Charact. 9(3):269-280.

Antal T.,Tarek-Tilistyák J., Cziáky Z.and Sinka L. 2017. Comparison of drying and quality characteristics of pear (Pyrus communisL.) using mid-infrared-freeze drying and single stage of freeze drying. Int. J. Food Eng. 13(4):125-146.

Crank J. 1975. “Mathematics of Diffusions” 2nd ed. Oxford University Press, London.

Das S., Das T., Rao P.S. and Jain R.K. 2001. Development of an air recirculating tray dryer for high moisture biological materials. J. Food Eng. 50(4):223-227.

Diamente L.M. and Munro P.A. 1993. Mathematical modeling of the thin layer solar drying of sweet potato slices. Sol. Energy. 51(4):271-276.

Doymaz I. 2004. Effect of dipping treatment on air drying of plums. J. Food Eng. 64(4):465-470.

Doymaz I. 2010. Effect of citric acid and blanching pre-treatments on drying and rehydration of Amasya red apples. Food Bioprod. Process. 88(2-3):124-132.

Doymaz ?. and ?smail O. 2012. Experimental characterization and modelling of drying of pear slices. Food Sci. Biotechnol. 21(5):1377-1381.

Doymaz ?. 2013. Experimental study on drying of pear slices in a convective dryer. Int. J. Food Sci. Technol. 48(9):1909-1915.

Dumano?lu H., Güne? N.T., Erdo?an V., Aygün A. and ?an B. 2006. Clonal selection of a winter-type European pear cultivar 'Ankara' (Pyrus communisL.). Turk. J. Agric. For. 30(5):355-363.

Elicin A.K. and Sacilik K. 2005. An experimental study for solar tunnel drying of apple. J Agr. Sci. 11(2), 207-211.

Erdo?an V., Aygün A., ?an B., Koltarla A., Güne? N. and Dumano?lu H. 2007. ‘Ankara’ armudu (Pyrus communisL.) klonlar?n?n RAPD tekni?i ile moleküler analizi. Türkiye V. Ulusal Bahçe Bitkileri Kongresi, Bildiriler Kitab?, Cilt 1, pp.56-59, Türkiye.

FAOSTAT.2019. Statistical database. Available: www.fao.org.

González-Martínez C., Cháfer M., Xue K. and Chiralt A. 2006. Effect of the osmotic pre-treatment on the convective air drying kinetics of pear var. Blanquilla. Int. J. Food Prop.9(3):541-549.

Hebda T., Brzychczyk B., Lapczynska-Kordon B. and Styks J. 2019. Influence of pretreatment and drying methods on process of rehydration of dried apple. Eng. for Rural Dev. 18:669-676.

Henderson S.M. 1974. Progress in developing the thin-layer drying equation. T ASAE. 17:1167-1168/1172.

Izli N., Taskin O. and Izli G. 2019. Drying of lime slices by microwave and combined microwave-convective methods. Ital. J. Food Sci.31(3):487-500.

Karadeniz F. 1999. Armut suyunun kimyasal bile?imi üzerine ara?t?rma. Turk. J. Agric. For.23(3):355-358.

Krokida M.K. and Marinos-Kouris D. 2003. Rehydration kinetics of dehydrated products. J.Food Eng. 57(1):1-7.

Maskan M. 2000. Microwave/air and microwave finish drying of banana. J. Food Eng. 44(2):71-78.

Midilli A., Kucuk H. and Yapar Z. 2002. A new model for single-layer drying. Drying Technol.20(7):1503-1513.

Pandey O.P., Mishra B.K. and Misra A. 2019. Comparative study of green peas using with blanching and without blanching techniques. Information Processing in Agriculture, 6(2):285-296.

Park K.J., Bin A. and Brod F.P.R. 2002. Drying of pear d’Anjou with and without osmotic dehydration. J. Food Eng. 56(1):97-103.

Prakash S., Jha S.K. and Datta N. 2004. Performance evaluation of blanched carrots dried by three different driers. J. Food Eng. 62(3):305-313.

Rizvi S.S.H. 1986. “Thermodynamic properties of foods in dehydration” In: M.A.Rao and S.S.H. Rizvi (Eds.), Engineering properties of foods, Marcel Dekker, New York.

Quiles A., Hernando I., Pérez-Munuera I., Larrea V., Llorca E. and Lluch M.Á. 2005. Polyphenoloxidase (PPO) activity and osmotic dehydration in Granny Smith apple. J. Sci. Food Agric. 85(6):1017-1020.

Sacilik K. and Unal G. 2005. Dehydration Characteristics of Kastamonu Garlic Slices. Biosyst. Eng. 92(2):207-215.

Sacilik K. and Elicin A.K. 2006. The thin layer drying characteristics of organic apple slices. J. Food Eng. 73(3):281-289.

Sacilik K., Elicin A.K. and Unal H.G. 2006. Drying kinetics of Üryani plum in a convective hot-air dryer. J. Food Eng. 76(3):362-368.

Sacilik K., Yurtlu Y.B. and Unal H.G. 2010. Thin layer convective drying and mathematical modeling of einkorn. Conference Proceeding -4th International Conference, TAE 2010: Trends in Agricultural Engineering, pp. 540-548, Prague; Czech Republic, September 7-10.

Sing, S., Raina C.S., Bawa A.S. and Saxena D.S. 2006. Effect of pretreatments on drying and rehydration kinetics and color of sweet potato slices. Drying Technol. 24(11):1487-1494.

Taskin O., Polat A., Izli N. and Asik B.B. 2019. Intermittent Microwave-Vacuum Drying Effects on Pears. Pol. J. Food Nutr. Sci. 69(1):101-108.

Vardin H. and Yilmaz F.M. 2018. The effect of blanching pre-treatment on the drying kinetics, thermal degradation of phenolic compounds and hydroxymethyl furfural formation in pomegranate arils. Ital. J. Food Sci. 30(1):156-169.

Wang J. and Chao Y. 2003. Effect of 60Co irradiation on drying characteristics of apple. J. Food Eng. 56(4):347-351.

Yurtlu Y.B. 2011. Drying characteristics of bay laurel (Laurus nobilisL.) fruits in a convective hot-air dryer. Afr. J. Biotechnol. 10(47):9593-9599.

Yagcioglu A., Degirmencioglu A. and Cagatay F. 1999. Drying characteristics of laurel leaves under different drying conditions. In Proceedings of the 7th International Congress on Agricultural Mechanization and Energy, pp. 565-569, Adana, Turkey, May 26-27.

Yald?z O. and Ertekin C. 2001. Thin layer solar drying some different vegetables. Drying Technol. 19(3):583-596.