Automatically generated rough PDF by ProofCheck from River Valley Technologies Ltd DE GRUYTER International Journal of Food Engineering. 2019; 20170302 Kashif Ghafoor 1 / Isam A. Mohamed Ahmed 1 / Süleyman Doğu 2 / Nurhan Uslu 3 / Gbemisola J. Fadimu 1 / Fahad Al Juhaimi 1 / Elfadıl E Babiker 1 / Mehmet Musa Özcan 3 The Effect of Heating Temperature on Total Phenolic Content, Antioxidant Activity, and Phenolic Compounds of Plum and Mahaleb Fruits 1 Department of Food Science & Nutrition, College of Food and Agricultural Sciences, King Saud University, Riyadh 11451, Saudi Arabia, E-mail: kghafoor@ksu.edu.sa, iali@ksu.edu.sa, fadimugbemisola@gmail.com, fahadaljuhaimi@hotmail.com, elfadilbabiker@yahoo.com 2 Department of Science, Ahmet Keleşoğlu Faculty of Education, Necmettin Erbakan University, Konya 42090, Turkey, E-mail: suleymandogu@gmail.com 3 Department of Food Engineering, Faculty of Agriculture, University of Selçuk, Konya 42079, Turkey, E-mail: nurhanuslu.gmuh@gmail.com,mozcan@selcuk.edu.tr Abstract: The efect of heating at diferent temperatures (60, 80, 90, 110, and 130 °C) on the total phenolic content, antiox- idant activity, and phenolic compounds present in plum and mahaleb fruits was investigated. The antioxidant activity values and total phenolic contents of fresh plum (93.82% measured by DPPH method, 787.79 mg gallic acid equivalent (GAE)/100 g dry weight determined by Folin method) and mahaleb fruits (81.80%, 634.47 mg GAE/100 g dry weight) were higher than plum and mahaleb fruits dried at diferent temperatures (p < 0.05). Generally, the heating process caused a reduction in both total phenolic content and antioxidant activity for plum and mahaleb. While (+)-catechin (92.62 mg/kg), 1,2-dihydroxybenzene (132.15 mg/kg), gallic acid (107.01 mg/kg), and 3,4-dihydroxybenzoic acid (74.59 mg/kg) are the key phenolic compounds in fresh plum, (+)-catechin, 3,4-dihydroxybenzoic acid, 1,2-dihydroxybenzene, and syringic and cafeic acids were the major phenolic compounds of mahaleb fruits. The polyphenol content of fruits and the class of phenolics present are signifcantly afected by heating temperature. Keywords: plum, mahaleb, fruit (cherry), oven drying, total phenol, antioxidant, phenolic compound DOI: 10.1515/ijfe-2017-0302 Received: October 18, 2016; Revised: October 21, 2019; Accepted: October 27, 2019 1 Introduction The genus Prunus encompasses plants belong to the Rosaceae family. Prunus mahaleb L. (Syn Cerasus mahaleb L. Mill.-Rosaceae) is a perennial small tree [1]. Ground mahaleb fruit and kernels are mixed with white four for their unique fragrance and then used in home baking and theconfectionery industry. Plums are a signif- cant source of favonoids, phenolic acids, anthocyanins, and other phenolics (tannins), which exhibit antioxi- dant properties [2]. Hydroxycinnamic acid derivatives, such as chlorogenic acid and neochlorogenic acid have been identifed as the predominant phenolic compounds of plums [3, 4]. Dried plum is known to be a healthy food in western countries. The principal phytochemicals in dried plums are phenols, including phenolic acid derivatives, favonoids, and coumarins [5, 6]. The polyphenolic compounds not only provide sensory prop- erties, such as color and taste, but also antioxidant, anticancer, antimicrobial, antiallergenic, antimutagenic, anti-infammatory, and antithrombotic properties [7–10]. Prunus species are mainly consumed as fresh fruits, processed sweets, jams, juices, candies, and natural sweeteners in pharmaceutical products [1]. In folk medicine, mahaleb fruits and seeds have been used as a tonic for the heart and a traditional medicine for diabetes and gastrointestinal problems [11]. The shelf life of fresh fruits and vegetables is short because of their high mois- ture content and water activity [12]. Dehydration processes such as sun drying, osmotic dehydration, hot air drying, vacuum drying, and microwave drying cause physical and chemical changes in fruits and increase shelf Kashif Ghafoor, Mehmet Musa Özcan are the corresponding authors. © 2019 Walter de Gruyter GmbH, Berlin/Boston. 1 Brought to you by | The University of Texas at Austin Authenticated Download Date | 1/20/20 1:06 PM