LWT - Food Science and Technology xxx (xxxx) xxx Please cite this article as: Khai Shin Hew, LWT - Food Science and Technology, https://doi.org/10.1016/j.lwt.2020.110612 Available online 21 November 2020 0023-6438/© 2020 Elsevier Ltd. All rights reserved. Mitigation of 3-monochloropropane-1,2-diol esters and glycidyl esters in refned palm oil: A new and optimized approach Khai Shin Hew a , Yih Phing Khor a , Tai Boon Tan a , Masni Mat Yusoff a , Oi Ming Lai b , Ahmad Jaril Asis c , Fahad A. Alharthi d , Imededdine Arbi Nehdi d , Chin Ping Tan a, * a Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia b Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, UPM, Serdang, Selangor, Malaysia c Sime Darby Research Sdn Bhd, 42960 Pulau Carey, Kuala Langat, Selangor, Malaysia d Chemistry Department, College of Science, King Saud University, P.O. BOX 2455, Riyadh, 11451, Saudi Arabia A R T I C L E INFO Keywords: Response surface methodology Physical oil refning Esters mitigation Separation-free water degumming Deodorization ABSTRACT Refned, bleached and deodorized palm oil (RBDPO) is reported to contain high amount of 3-monochloropro- pane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) due to high-temperature deodorization step and rich in organochlorines. Therefore, a new palm oil refning process was developed to mitigate this problem. The conventional physical refning process was modifed and optimized using response surface methodology with selected processing parameters (water and acid dosages, pre-treatment and deodorization temperatures and deodorization duration). Formation of esters in oil during refning was modelled, and a new refning approach which had been optimized and validated was developed. The new method achieved signifcant reduction in ester contents (78% reduction for 3-MCPDE, 53% reduction for GE; p < 0.05), with free fatty acid content and color maintained at < 1.0% and < 3.0 R. Similar mitigation effect was confrmed by testing the new refning approach with different grades of crude palm oil. 1. Introduction The ultimate goal of palm oil refning is to produce high-quality refned oil by removing undesirable compounds from oil, thereby making the oil safe for human consumption. High-quality refned palm oil is a broad term. The traits of high-quality refned, bleached and deodorized palm oil (RBDPO) could be categorized into three main as- pects: organoleptic quality, stability and nutritional quality (Gibon, De Greyt, & Kellens, 2007). In terms of organoleptic quality, to fulfll the common sensorial perceptions that consumers have towards RBDPO, it should possess qualities such as light color, bland taste and lack of odor (Lai, Tan, & Akoh, 2012). Besides, oil should also have a long shelf life, good oxidative stability and high nutritional value (O’Brien, 2008) including controlled levels of benefcial compounds (such as toco- trienols, tocopherols and phytosterols) and hazardous contaminants (such as polycyclic aromatic hydrocarbons, pesticides, dioxins, trans fatty acids, 3-monochloropropane-1,2-diol esters (3-MCPDE) and gly- cidyl esters (GE)) simultaneously. All these traits of high-quality RBDPO are strongly related to the oil refning process. In recent publications, it was consistently reported that high amount of 3-MCPDE and GE were generated during the refning process of palm oil (Craft, Nagy, Sandoz, & Destaillats, 2012; Hrncirik & van Duijn, 2011). The detected 3-MCPDE and GE contents in refned palm oil ranged from 2.16 to 15.2 mg/kg (Larsen, 2009; Weißhaar & Perz, 2010) and 0.30–18.00 mg/kg (Cheng, Liu, & Liu, 2016; Kuhlmann, 2011; Weißhaar & Perz, 2010), respectively, while the esters level in other oil types such as maize oil, olive oil, soybean oil and etc. remained remarkably low (48–608 μg/kg for 3-MCPDE and 15–650 μg/kg for GE, (EFSA, 2016)(. Both esters are proven to be carcinogenic when they are completely hydrolyzed into their free form in gastrointestinal tract in human body. 3-MCPD has been identifed as a non-genotoxic threshold carcinogen that primarily affects kidneys and male fertility, while gly- cidol is known as a genotoxic non-threshold carcinogen with various toxicity evidences found in animal studies (EFSA et al., 2018, EFSA, 2016). Although palm oil is enriched with high content of natural an- tioxidants like vitamin E and carotenoids, at the same time the esters formation inhibitory capacities of antioxidants were confrmed when added into oils (Li et al., 2015), there is still no evidence showing that * Corresponding author. E-mail address: tancp@upm.edu.my (C.P. Tan). Contents lists available at ScienceDirect LWT journal homepage: www.elsevier.com/locate/lwt https://doi.org/10.1016/j.lwt.2020.110612 Received 20 May 2020; Received in revised form 16 November 2020; Accepted 17 November 2020