Contents lists available at ScienceDirect Industrial Crops & Products journal homepage: www.elsevier.com/locate/indcrop Development and optimization of the new ultrasonic-infrared-vacuum dryer in drying Kelussia odoratissima and its comparison with conventional methods Bahram Hosseinzadeh Samani a , Hooman Gudarzi a , Sajad Rostami a , Zahra Lorigooini b, ⁎ , Zahra Esmaeili a , Fatemeh Jamshidi-kia b a Department of Mechanical Engineering of Biosystems, Shahrekord University, Iran b Medical Plants Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran ARTICLE INFO Keywords: Ultrasonic Infrared Kelussia odoratissima Medicinal plants ABSTRACT Among the post-harvest processing of medicinal plants, drying is an important and influential process. Given the numerous applications of medicinal plants, especially Kelussia odoratissima, in the food and pharmaceutical industries, the aim of this study was to compare the effects of the ultrasound-infrared radiation-vacuum method with conventional drying methods on the drying time, the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of K. odoratissima. ANOVA result showed that the effects of drying methods, drying temperature and their interaction effect on phenolic, flavonoid and antioxidant content were significant at 1% probability level. In the ultrasound-IR-vacuum method, by increasing temperature from 40 °C to 80 °C, the TFC increased by 35%. The highest antioxidant capacity was obtained for dry shade treatment, followed by dry sun treatment and three temperatures, i.e., 40 °C, 60 °C and 80 °C, in the combined method. The proposed op- timal temperatures for the hot air, IR, and ultrasonic drying, were 63 °C, 66 °C and 71 °C, respectively. 1. Introduction Aromatic and medicinal plants, as an important natural source, can be used as additives (Behruzian et al., 2017; Jamshidi-Kia et al., 2018) or natural antioxidants in the food and pharmaceutical industries due to their pharmacological properties, more safely than synthetic materials (Calín-Sánchez et al., 2011). In addition to the factors related to pre- harvest processing, which affect the quality of the active ingredients derived from medicinal plants, also post-harvest handling also affects medicinal plants’ quality. (Hosseinzadeh et al., 2011; Omidbaigi, 2005). Besides the plants’ inherent biochemical properties, harvest conditions, cultivation, geographical and environmental factors, and postharvest processes play a vital role in the quantity and quality of secondary metabolites, and consequently the biological and medicinal uses of medicinal plants and aromatic herbs (Hassanpouraghdam et al., 2010). The results of the studies on the qualitative characteristics of medicinal and culinary plants have demonstrated the effects of pre- and post- harvest factors, and in some cases, their interaction effects in this regard (Ippolito and Nigro, 2000; Subasinghe, 2011). Among the post-harvest handling methods of medicinal plants, drying is an important and influential process. The main objective of the drying process is to reduce the water level to less than 15% to in- hibit microbial growth and minimize biochemical changes, to preserve the characteristics of the color and aroma, and to maintain the active ingredients and the final products’ quality (Tanko et al., 2005). Several studies have been conducted to investigate the effect of drying on medicinal plants in recent years. Modern technologies have also being seeking to minimize changes in plant quality (Orphanides et al., 2016). In addition, drying leads to a reduction in the weight and volume of the product, which facilitates its storage and transportation, and increases its shelf life. Several experimental studies on the effects of drying methods on the amount and constituents of the active ingredients of medicinal and aromatic plants have indicated that proper drying methods must be selected depending on the type of plant species, the type of active ingredient, and the type of plant tissue (storage location of the active ingredient), and to this end, the use of new methods and their comparison with the common drying methods of drying can be greatly helpful (Ahmadi et al., 2008; Azizi et al., 2009; Omidbaigi et al., 2004; Sefidkon et al., 2006). Traditional and old methods such as natural drying (drying in shade and sun) and hot air drying are still the most important methods used for the production of dry plant material due to the use of minimal https://doi.org/10.1016/j.indcrop.2018.06.053 Received 10 March 2018; Received in revised form 1 June 2018; Accepted 12 June 2018 ⁎ Corresponding author. E-mail address: gueini.z@skums.ac.ir (Z. Lorigooini). Industrial Crops & Products 123 (2018) 46–54 0926-6690/ © 2018 Elsevier B.V. All rights reserved. T