Current Trends in Natural Sciences Vol. 11, Issue 21, pp. 79-87, 2022 https://doi.org/10.47068/ctns.2022.v11i21.008 Current Trends in Natural Sciences (on-line) Current Trends in Natural Sciences (CD-Rom) ISSN: 2284-953X ISSN: 2284-9521 ISSN-L: 2284-9521 ISSN-L: 2284-9521 http://www.natsci.upit.ro *Corresponding author, E-mail address: necaticetin@erciyes.edu.tr 79 EFFECT OF PRE-TREATMENTS ASSISTED MICROWAVE DRYING ON KINETICS AND ENERGY ASPECTS OF DRAGON FRUIT Necati Çetin 1,* , Seda Günaydın 1 , Kevser Karaman 2 , Cevdet Sağlam 1 1 Erciyes University, Faculty of Agriculture, Department of Biosystems Engineering, 38039, Kayseri, Turkey 2 Erciyes University, Faculty of Agriculture, Department of Agricultural Biotechnology, 38039, Kayseri, Turkey Abstract Drying is one of the most effective preservation methods applied to increase the shelf life of agricultural products. In this study, the effect of different pre-treatments on drying dragon fruit with a microwave was investigated. It is also aimed to determine the drying method with the minimum energy consumption. Dragon fruit slices were dried by microwave at 300 W output power in four different pretreatments as ultrasound, gum arabic, sucrose, and without pretreatment. Pretreatment applications were carried out by performing ultrasound for 10 minutes on dragon fruit slices and soaking them in 10% gum arabic and sucrose solutions before drying. Results showed that the shortest and longest drying times were measured in gum arabic and without pretreatment, respectively. Time-dependent estimation data were calculated by six different thin-layer drying models, considering the drying times and moisture rates. Jena&Das model showed the best fitting performance. As a result, it has been determined that pretreatment applications reduce drying time and energy consumption. In addition, gum arabic pre-treatment is advantageous in terms of energy consumption in microwave drying of dragon fruit. Keywords: Dragon fruit, drying, modeling, energy, pre-treatment, 1. INTRODUCTION Dragon fruit (Hylocereus), belong to the cactus family, is a tropical fruit with red or white flesh and small black seeds. It is known to be native to Mexico, North, Central and South America (Yong et al., 2018; Morillo et al., 2022). Many kinds of foods are made from the fruit part of the dragon fruit, or a soft drink is obtained by squeezing the juice (Nurani and Sulistyoningsih, 2021). It is also used as a colorant with other food products (Attar et al., 2022). Dragon fruit is rich in riboflavin, niacin, thiamine vitamins and phosphorus (P), potassium (K), calcium (Ca), iron (Fe), minerals and polyphenol, betalain, anthocyanin. In addition, the steroid content is high, which strengthens immunity, reduces stress, and increases kidney function (Sari et al., 2021). Dragon fruit protects against infectious diseases, prevents cancer, regulates blood sugar, strengthens the digestive system and improves respiratory tract diseases (Nur Izalin et al., 2016; Prisa, 2022). Fresh fruits and vegetables deteriorate in a short time due to the intense moisture they contain shortly after harvest (Morad et al., 2017). In order to prevent this and increase the shelf life of the products, the drying technique is widely used (Adeleye et al., 2020). Drying is the simultaneous transfer of heat and mass. The high moisture content in the structure of the products is reduced to a value where the microorganism activity ceases (Günaydın et al., 2022). Drying process limits the