Effect of Infrared Drying on Qualitative Characteristics of Sumac Fruit (Rhus coriaria L.)

Document Type : Research Article


1 Graduated Student Department of Biosystems Engineering, Tarbiat Modares University, Tehran, Iran,

2 Tehran


Introduction: Drying of medicinal and aromatic plants (MAPs) is a widely spread method offering physico-chemical stabilization by taking away part of the moisture content, producing different products with different qualitative properties and economical value. The main purpose of MAPs drying is to extend product shelf life, minimize packaging requirements and reduce shipping weights. Drying is used to stop the growth of microorganisms and preserve the quality of MAPs. There are different drying methods and their suitability can be determined by energy efficiency, drying time, preservation of active substances and other quality properties of the product, depending on market demand. Therefore, determining a suitable drying method to achieve higher active substances in medicinal plants is very important. Advantages of infrared drying include high efficiency of conversion of electrical energy into heat, a suitable alternative source for thermal energy, and uniform heating of the product surface. The aim of this study was to investigate the effect of infrared drying on drying time and the qualitative characteristics of sumac fruit (total color changes, total phenolic content, organic acids, and vitamin C).
Material and Methods: Sumac fruits (from the forests of Sardasht city in West Azerbaijan Province, Iran) were used after complete separation from clusters and additional parts for drying and performing the desired treatments. In this research, an infrared dryer was used to dry the sumac sample which was made by the Department of Biosystems Engineering of Tarbiat Modares University. For this study, a factorial experiment was performed based on a completely randomized design. In this experiments, three levels of radiation intensity (0.2, 0.3 and 0.5 watts per square centimeter) and three levels of air velocity (0.5, 1 and 1.5 meters per second) were used. The sample tray inside the dryer was connected by a rod to a digital scale at the bottom of the dryer. The scale had a computer connection port that could measure and record the weight of the fruits continuously during drying. To determine the initial moisture content, 3 samples (50 g) were placed in an oven at 105 °C and after three hours, the samples were taken out of the oven and weighed, and finally the moisture content of the product was calculated on wet basis. The initial moisture content of sumac fruits was approximately 17%. Drying was continued until the product reached a moisture content of 7%. Drying time and quality characteristics of sumac fruit (color changes, total phenolic content, organic acids, and vitamin C) were measured. Colorimeter (Hunterlab, Color Flex model, USA) was used to check the color changes of sumac fruits during drying and the total color changes ( ) compared to the fresh sample were calculated. To measure the total phenolic content, Folin-Ciocalteu phenol reagent was used by a spectrophotometer (Samsung, Smart Spec Flus model, South Korea). Titration method was used to measure vitamin C and organic acids. Finally, based on all the mentioned parameters, the optimization was performed by Design Expert software (version 10) and the best score was obtained based on the utility index.
Results and Discussion: The results showed that the intensity of infrared radiation and air velocity had a significant effect on the studied characteristics except total phenolic content. The minimum and maximum drying times were obtained at the highest and lowest infrared intensities and air velocities, respectively. Increasing the infrared intensity and subsequently increasing the temperature had a negative effect on the total color changes, organic acids and vitamin C, so that the least total color changes and the highest amount of organic acids and vitamin C were obtained by reducing the intensity of infrared radiation. The lowest total color change and the highest amount of organic acids were obtained in the treatment of 0.2 W cm-2 × 1.5 m s-1 and the highest amount of vitamin C in 0.2 W cm-2 × 1 m s-1 and 0.3 W cm-2 × 0.5 m s-1 treatments, respectively. The values obtained from the optimization parameters for the studied indicators (drying time, total color changes, organic acids, and vitamin C) showed that the best point for drying of sumac fruit was the infrared radiation intensity of 0.3 W cm-2 and air velocity of 0.5 m s-1. In this treatment, the highest utility index obtained by software was 0.71.
Conclusion: Infrared drying reduced the drying time of sumac fruit compared to traditional drying methods (shade and sun drying). In addition to reducing the drying time, infrared drying was a suitable method for preserving the phytochemical properties and color changes of sumac fruits.


1- Aghbashlo M., Kanmehr M., and Samimi-Akhijahani H. 2008. Influence of drying conditions on the effective moisture diffusivity. Energy of activation and energy consumption during the thin layer drying of Berberis fruit (Berberidaceae). Energy Conversion and Management 49: 2865-2871.
2- Amiri Chayjan R., Tabatabaei Bahrabad S.M., and Rahimi S.F. 2013. Modeling infrared-covective drying of pistachio nuts under fixed and fluidized bed conditions. Journal of Food Process 38(3): 1224-1233.
3- Bagheri S., Muhd Julkapli N., and Bee Abd Hamid S. 2014. Titanium dioxide as a catalyst support in heterogeneous catalysis. The Scientific World Journal 1-21.
4- Baysal T., Icier F., Ersus S., and Yildiz H. 2003. Effects of microwave and infrared drying on the quality of carrot and garlic. European Food Research and Technology 218: 68-73.
5- Bezerra M.A., Santelli R.E., Oliveira E.P., Villar L.S., and Escaleira L.A. 2008. Response surface methodology (RSM) as a tool for optimization in analytical chemistry. Talanta 76(5): 965-977.
6- Caliskan G., and Dirim S.N. 2013. The effects of the different drying conditions and the amounts of maltodextrin addition during spray drying of sumac extract. Food and Bioproducts Processing 91(4): 539-548.
7- Das I., Das S.K. and Bal S. 2004. Specific energy and quality aspects of infrared (IR) dried parboiled rice. Journal of Food Engineering 62: 9-14.
8- Dwivedy S., Rayaguru1 K. and Sahoo G.R. 2012. Effect of drying methods on quality characteristics of medicinal Indian borage (Coleus aromaticus) leaves. Journal of Food Process Technology 3: 188-194.
9- Delgado B., Palop A. and Fenandez P.S. 2004. Combined effect of thymol and cymene to control the growth of Bacillus cereus vegetative cells. European Food Research and Technology 218(3): 188-193.
10- Hamrouni Sellami I., Wannes W.A., Bettaieb Rebey I., Berrima S., Chahed T., Marzouk B. and Limam F. 2011. Qualitative and quantitative changes in the essential oil of Laurus nobilis L. leaves as affected by different drying methods. Food Chemistry 126(2): 691-697.
11- Hasani A., Khoshtaghaza M.H. and Ebadi M.T. 2019. Effect of different drying methods (microwave drying, shade and sun drying) on the quality of sumac fruit (Rhus coriaria L.). Iranian Journal of Medicinal and Aromatic Plants Research 36(1): 142-154. (In Persian with English abstract)
12- Hebbar H.U., Viswanathan K.H. and Ramesh M.N. 2004. Development of combined infrared and hot air dryer for vegetables. Journal of Food Engineering 65(4): 557-563.
13- Jun S., Krishnamurthy K., Irudayaraj J. and Demirci A. 2011. Fundamentals and theory of infrared radiation. In, Pan, Z. Atungulu, G. G. (Eds.). Infrared Heating for Food and Agricultural Processing. CRC press, New York.
14- Kantrong H., Tansakul A. and Mittal G.S. 2014. Drying characteristics and quality of shiitake mushroom undergoing microwave-vacuum drying and microwave-vacuum combined with infrared drying. Journal of Food Science and Technology 51(12): 3594-3608.
15- Khayyat S.A. and Roselin L.S. 2018. Recent progress in photochemical reaction on main components of some essential oils. Journal of Saudi Chemical Society 22(7): 855-875.
16- Khir R., Pan Z., Salim A., Hartsough B.R. and Mohamed S. 2011. Moisture diffusivity of rough rice under infrared radiation drying. LWT - Food Science and Technology 44: 1126-1132.
17- Kizil S., and Turk M. 2010. Microelement contents and fatty acid compositions of Rhus coriaria L. and Pistacia terebinthus L. fruits spread commonly in the south eastern Anatolia region of Turkey. Natural Product Res 24: 92-98.
18- Koller W.D. 1987. Proceeding of the fifth Int. Flavour Conference, Porto Karras. Chalkidiki, Greece. Problems with the Flavour of Herbs and Spices 123-132.
19- Miranda M., Maureira H., Rodriguez K. and Vegalvez A. 2008. Influence of temperature on the drying kinetics, physicochemical properties, and antioxidant capacity of Aloe vera (Aloe barbadensis Miller) gel. Journal of Food Engineering 91: 297-304.
20- Mujumdar A.S. 2006. Handbook of Industrial Drying. CRC Press, New York.
21- Mohajeran S., Khoushtaghaza M.H. and Moazami Goudarzi A. 2003. Effect of rough rice temperature and air velocity on grain crack during infrared radiation drying. Iranian Journal of Food Science and Technology 3(2): 57-65. (In Persian with English abstract)
22- Mumivand H., Rezaei Nejad A.H., Taghipour S., Sepahvand K. and Moradi B. 2019. Effect of different drying methods on drying time and some phytochemical characteristic of pelargonium (Pelargonium graveolens). Journal of Horticulture Science 33(4): 655-668. (In Persian with English abstract)
23- Motevali A., Minaei S., Banakar A., Ghobadian B and Khoshtaghaza M.H. 2014. Comparison of energy parameters in various dryers. Energy Conversion and Management 87: 711-725.
24- Musci M., and Yao S. 2017. Optimization and validation of Folin_Ciocalteu method for the determination of total polytionol content of Puerh tea. International Journal of Food Sciences and Nutrition 68(8):913-918.
25- Nadjafi F., Ebadi M.T. and Abbasian J. 2012. Medicinal and Aromatic Crops: Harvesting, Drying and Processing (Translation). Shahid Beheshti University Press, Tehran, 380p. (In Persian with English abstract)
26- Nielson S.S. 2010. Food Analysis. Spiringer, New York.
27- Ozcan M., and Erkmen O. 2001. Antimicrobial activity of the essential oil of Turkish plant spices. European Food Research and Technology 212(1): 658-660.
28- Paakkonen K., Havento J. and Galambosi B. 1999. Infrared drying of herbs (Research Note). Agricultural and Food Science 8(1): 19-27.
29- Ponkham K., Meeso N., Soponronnarit S. and Siriamornpun S. 2012. Modeling of combined far-infrared radiation and air drying of a ring shaped-pineapple with/without shrinkage. Food and Bioproducts Processing 90(2): 155-164.
30- Raghavan B., Rao L.J., Singh M. and Abraham K.O. 1997. Effect of drying methods on the flavor quality of marjoram (Origanum majorana L.). Nahrung 41(3): 159-161.
31- Rahmati M., Azizi M., Ebadi M.T., and Hasanzadeh Khayyat M. 2010. Study on the effects of different drying methods on weight loss rate, essential oil and chamazolene contents of chamomile (Matricaria recutita CV. Germania (Diploid)) flowers. Journal of Horticulture Science 24(1):29-37. (In Persian with English abstract)
32- Reyna S. and Mazza G. 2007. Biological activities of extracts from sumac (Rhus spp.) a review. Plant Foods for Human Nutrition 62: 165-175.
33- Salehi F., Kashaninejad M., Sadeghi Mahoonak A., and Ziaiifar A. 2015. Button Mushroom Drying Process by Infrared System. Innovative Food Science and Technologies 13: 99-101. (In Persian with English abstract)
34- Samani B.H., Gudarzi H., Rostami R., Esmaeili Z., and Jamshidi-kia F. 2018. Development and optimization of the new ultrasonic-infrared-vacuum dryer in drying Kelussia odoratissima and its comparison with conventional methods. Industrial Crops and Products 123: 46-54.
35- Seyed Abadi M.M., Aghajanzadeh Soorki S., Kashani Nezhad M. and Ziyai Far A.M. 2016. Investigation of the effect of microwave on some physicochemical properties of sour orange juice. Journal of Food Scientist Technology 14(62): 17-29.
36- Shahabi M., Rafiee S., Mohtasebi S.S., and Hosseinpour S. 2014. Image analysis and green tea color change kinetics during thin-layer drying. Food Science and Technology International 20: 465-476.
37- Strumillo C. and Kudra T. 1987. Drying Principles, Applications and Design. Gordon and Breach Science Publisher, USA.
38- Therdthai N. and Zhou W. 2009. Characterization of microwave vacuum drying and hot air drying of mint leaves (Mentha cordifolia Opiz ex Fresen). Journal of Food Engineering 91(3): 482-489.
39- Wang J. and Xi Y.S. 2005. Drying characteristics and drying quality of carrot using a two-stage microwave process. Journal of Food Engineering 68: 505–511.
Volume 34, Issue 3 - Serial Number 47
November 2020
Pages 493-504
  • Receive Date: 08 January 2020
  • Revise Date: 26 August 2020
  • Accept Date: 31 August 2020
  • First Publish Date: 21 November 2020