processes Article Establishment of an Effective Refining Process for Moringa oleifera Kernel Oil Husna Madihah Abd Hadi 1 , Chin Ping Tan 1 , Nur Khalishah Mohamad Shah 1 , Tai Boon Tan 2 , Keshavan Niranjan 3 and Masni Mat Yusoff 1, *   Citation: Abd Hadi, H.M.; Tan, C.P.; Mohamad Shah, N.K.; Tan, T.B.; Niranjan, K.; Mat Yusoff, M. Establishment of an Effective Refining Process for Moringa oleifera Kernel Oil. Processes 2021, 9, 579. https://dx.doi.org/10.3390/pr9040579 Received: 22 October 2020 Accepted: 16 November 2020 Published: 26 March 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Seri Kembangan 43400, Selangor, Malaysia; husnamadihah12@gmail.com (H.M.A.H.); tancp@upm.edu.my (C.P.T.); spashakhal@gmail.com (N.K.M.S.) 2 Department of Food Service and Management, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Seri Kembangan 43400, Selangor, Malaysia; taiboon_tan@upm.edu.my 3 Department of Food and Nutritional Sciences, University of Reading, Whiteknights, Reading RG6 6AP, UK; afsniran@reading.ac.uk * Correspondence: masniyusoff@upm.edu.my; Tel.: +60-17-6068925 Abstract: This study systematically established the most effective refining process for Moringa oleifera (MO) kernel oil. Acid degumming (20.33 ± 1.37 ppm) removed significantly greater phosphorus than water degumming (31.18 ± 0.90 ppm). Neutralization was more effective than deodorization in decreasing the acid (0.06 mg KOH/g) and p-Anisidine (p-AV, 0.36 ± 0.03) values of the oil. Besides improving its color properties, acid-activated bleaching earth Type B was better than Types A and C in decreasing the oil’s p-AV (0.43 ± 0.02), acid value (3.96 ± 0.02 mg KOH/g), and moisture content (0.01 ± 0.00% w/w). The selected refining stages successfully produced MO kernel oil with acceptable peroxide value (PV, 1.66–3.33 meq/kg), p-AV (1.05–1.49), total oxidation value (TOTOX, 4.38–8.15), acid value (0.03 mg KOH/g), moisture content (0.01% w/w), phosphorus content (1.28–1.94 ppm), iodine value (80.79–81.03), oleic acid (79.52–79.65%), and tocopherol content (65.26–87.00 mg/kg). Keywords: fats and oils; oilseeds; oxidative stability; lipids; lipid chemistry/lipid analysis; processing technology; refining 1. Introduction Moringa oleifera (MO) is the most widely cultivated species of the Moringaceae fam- ily [1]. The plant is native to northern India, and is widely distributed throughout the tropics and subtropics, including Africa, Asia, Central, and South America due to its strong resistance to drought [2]. Almost every part of the plant (leaves, root bark, stem bark, immature pods, and mature seeds) is edible and valuable. From an economic point of view, MO is potentially one of the most valuable crops for food, industrial, agricultural, and medicinal uses, especially for addressing food security issues in countries where hunger and malnutrition are major problems [1]. One of the key parts of MO is its seed kernel, which can contain up to 35% (w/w) protein and 40% (w/w) edible oil [3]. Many studies have reported on the physicochemical and oxidative properties of MO kernel oil. These studies attributed its high stability to the presence of up to 75% oleic acid (i.e., comparable to olive oil), and significant amounts of tocopherol and sterol [4,5]. A diet rich in monounsaturated fat as a substitute for saturated fat is a strong and continuing trend due to its beneficial impact on coronary heart disease and overall heat [6]. With reference to these findings, MO kernel oil can potentially be developed and commercialized as healthy and functional food products. It can also be promoted as a new source of oil in tropical and subtropical countries since the tree grows rapidly under a wide range of climatic conditions with little or no agricultural input [2]. Processes 2021, 9, 579. https://doi.org/10.3390/pr9040579 https://www.mdpi.com/journal/processes