Biocatalysis and Agricultural Biotechnology 23 (2020) 101504 Available online 18 January 2020 1878-8181/© 2020 Published by Elsevier Ltd. Effect of microwave heating on lipid composition, oxidative stability, color value, chemical properties, and antioxidant activity of gurum (Citrulluslanatus var. Colocynthoide) seed oil Emad Karrar a, b , Sujitraj Sheth c , Wei Wei a , Xingguo Wang a, * a State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, China b Department of Food Engineering, Faculty of Engineering, University of Gezira, WadMedani, Sudan c Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi, China A R T I C L E INFO Keywords: Gurum seed oil Microwave heating Screw press Phyto-chemical properties Lipid composition Antioxidant activity ABSTRACT Gurum (Citrulluslanatus var. Colocynthoide) seeds were treated with microwave power of 800 W for 6 min at a frequency of 2450 MHz where the inner temperature of the seeds reached 146 � C. The oil was extracted with a screw press to investigate the impact on lipid composition, oxidative stability, color value, chemical properties, and antioxidant activity of gurum seed oil. The yield of oil extraction increased from 27.6% to 35.4%. Peroxide value was decreased from 0.75 meq of O 2 /kg of oil to 0.46 meq O 2 /kg, whereas acid value was increased from 0.68 mg of KOH/g of oil to 0.95 mg of KOH/g of oil. The polyphenol contents increased from 22.6 to 25.3 mg GAE/kg oil. The antioxidant activity increased from 59.2% to 64.7% after 4 min treatment but was 60.7% after 6 min. Oxidative stability increased from 4.01 h to 5.23 h. Triacylglycerol decreased from 96.9% to 92.9%, while the free fatty acids increased from 0.95% to 6.38%. The total of tocopherols contents decreased from 560 mg/ 100 g oil to 377 mg/100 g oil. The color value was found to increase with an increase in microwave heating at different times. 1. Introduction Contributed by increased consumers’ request for plant oils, fnding novel raw materials are permanently pursued and shape one of the key factors in the oils industry for improving proftability. Introducing new seed oil to the consumer, with high nutritional values and health- promoting advantages would be considered as one of the important defes for both industry and food technologists. Various studies have been lately focused on studying properties of many vegetable and fruit seed oils as a novel source of edible oil as well as explaining their appealing nutritional values. These seeds are considered as a by-product or waste such as Watermelon seed, pumpkin seed, and gurum seed (Karrar et al., 2018). Nowadays, there is also growing interested in the by-product of plants such as cucurbits seed due to their nutritional values and health benefts. Citrulluslanatus var. Colocynthoide, commonly known as gurum (a member of the cucurbits family, it is normally cultivated in the region of Sudan and Egypt. These seeds in Sudan are utilized as a formulation in traditional medicines and occasionally eaten as snacks (Karrar et al., 2019a, 2019b; Mariod et al., 2009). Gurum seed has high contents of oil; it can play an important role in the human health and nutrition because of the presence of fatty acids, tocopherols, sterols, and antioxidant ac- tivity. The oil content of gurum seed is varied between 27 and 35.5%, and the majority of the fatty acids present in gurum seed oil are linoleic acid accounting for about 67.56 - 61.96% (Karrar et al., 2019a, 2019b; Mariod et al., 2009). Gurum seed oil is appropriate edible oil as it con- tains long-chain fatty acids (C16–C20), and a rich source of unsaturated fatty acids (UFAs), and natural antioxidants. Extraction of vegetable oil from seeds in the oil industry can be performed either by solvent method or mechanical pressing. The extraction by the solvent method is most effective method with less oil residual in the seed, but such a method has some disadvantages in the at industrial production, such as it requires the use of high temperatures, poor quality products, high operation costs which lead to the addition of a step to remove solvent remains from the extract (Yang et al., 2013). Extraction of oil by the pressing method is easier and safer with little steps when to compare with the solvent method and also mechanical pressing is applied for seed with a higher content of oils, such as * Corresponding author. School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China. E-mail addresses: emadkarrar26@yahoo.com (E. Karrar), wxg1002@qq.com (X. Wang). Contents lists available at ScienceDirect Biocatalysis and Agricultural Biotechnology journal homepage: http://www.elsevier.com/locate/bab https://doi.org/10.1016/j.bcab.2020.101504 Received 5 November 2019; Received in revised form 10 January 2020; Accepted 14 January 2020